An article from PeterSmith.net.nz , written by Peter Smith www.petersmith.net.nz/boat-anchors/independent-performance-testing.php

Deception Island, Antarctica

Independent Anchor Performance Testing

Independent anchor performance testing

Published boat anchor testing is generally of poor quality. Much of it amounts to nothing better than noise: terrible test designs, absence of controls, lack of repeat trials, and commercial or even nationalist biases generate unhelpful data that confuse and distract. On this page is a collection of those few exceptions that manage to build an accurate and helpful picture of real world anchor performance.

Writers tend not to possess science or engineering backgrounds and lack understanding of what would constitute valid testing, much less reasonable analysis of the resulting data. Even if the publication boasts qualified personnel, testing of an acceptable standard is expensive and unlikely to ever become an activity a magazine will engage in. The three- or four-figure worth of a single article can never bring a financial return on the five- or six-figures of the necessary budget.

Commercial involvement with supposedly independent publications is a particularly insidious example of media failings. An example is a ‘test’ conducted in 2014 by Fortress Marine Anchors in the USA which was covered by a number of well-known publications. Without exception the write-ups included only cursory notes as to the testers’ commercial nature, glossed over as unimportant. Predictably, the results looked exactly as Fortress might prefer them, attending to both the championing of their own product and the disparagement of their most threatening marketplace competitors. In this case as always the testing methodology may be critiqued, such as a focus on a bottom type in the company’s favor; apples-to-oranges comparisons of aluminium to steel anchors, resulting in mismatched physical sizes; a pulling protocol designed to benefit their product rather than best simulate real world usage; and so on. In a follow-up in PassageMaker , author Nigel Calder debates test ‘witness’ and ex-West Marine corporate man Chuck Hawley, pointing out some of these issues and raising concerns based on discrepancies between the testing data and real world experience – Hawley doggedly maintains that the testing he witnessed was not rigged and that the results were credible. Similar claims were made by Practical Sailor , who took Fortress at their word and simply published supplied results without even bothering to send anyone. But the problem of any form of bias is very simple, and does not require deep arguments on methodology. In the world of science, where researching the facts of reality with a rigid impartiality is foundational, it is well understood how natural human biases in even the most neutral and competent experimentalist can totally invalidate otherwise carefully planned testing. Peer review will simply not accept results from research which has not taken great care to eliminate bias with basic techniques such as proper controls, randomization, and blind testing. All this before results are published by the mainstream media. The typical sports magazine staff and writers are unequipped, in terms of qualifications or scientific experience, to review a complicated test. And whether or not the cynical invite from the commercial party to ‘referee’ their testing is accepted, writers are expected to produce a pay-worthy draft that a magazine can dress up as useful to their readers. This alone is sufficient to introduce substantial bias on top of the existing commercial agenda. Such ‘independent’ witnesses, lacking scientific training, are bound to be misled. A clever salesman would rely on it. The publications involved in this kind of debacle allow, in their credulity or indolence, commercial agents to commandeer their reputation and do a tremendous disservice to their readers. The boating media needs to do a better job of maintaining impartiality.

While blemished, the picture is not universally bleak. The tests below manage to present credible data. For example: the West Marine testing, a product of the world’s largest marine retailer’s desire to test the anchors it distributes. Although obviously commercial, the testers at least uphold the appearance of brand-neutrality, and indeed their bestselling anchors (at the time) are those with the poorest results. A radically different example is John Knox’s work in Practical Boat Owner , a continuation of a long-time obsession with anchors – much more a labor of love than any mercenary effort by the magazine writer who fancies himself a research scientist for the day.

These tests are therefore overviewed here with an eye to their scientific credibility, a standard which leads to the rejection of a number of published articles. Tests are also restricted to those which include the Rocna or Vulcan, but have no connections to any anchor manufacturer.

Kippari March 2015

Kippari Magazine ”Ankkurit Testissä” March 2015

The Finns at Kippari (Skipper) conducted a small and simple comparison test on dry land, using an industrial sand and gravel pit. The substrate appeared consistent from location to location, which many other poorly controlled tests cannot match, although unfortunately it does not appear to have been realistically wet. Nevertheless the data for hard sand, where many contenders simply failed to set, is worthwhile, and in soft sand interesting differences are found too.

“The test’s top anchor for absolute grip and holding power” was the Rocna, although the magazine included Finnish retail pricing in their final consideration and slipped the New Zealand design down a spot as a consequence. They also considered dimensions and physical bulk of the anchors, with regard to bow roller fit. Only the pull data is reproduced here.

Kippari Magazine March 2015, Klaus Salkola, anchor test data

The results were not adjusted for the variance in mass between the anchor models tested, an irritating omission given there is a 20% variance between the lightest (10 kg) and the heaviest (12 kg) steel products, and a 47% variance if the aluminium Fortress is considered. The inclusion of the latter is always a problem for tests; the FX‑23 model chosen by Kippari is relatively large, and would weigh nearly 18 kg were the same design built from steel. Accordingly, the reader should really try to view the results on a size-for-size basis, especially if an anchor of different size to those tested here is required.

Voile Magazine May 2012

Voile Magazine «14 ancres sous haute tension» May 2012: Spade, Rocna, FOB Rock, Manson Supreme, Delta, Brake, Kobra 2, Buegel, SeaBlade, and Spoon

French magazine Voile has accrued a number of anchor tests to its name. Historically French products have been the focus, at the expense of other anchor types more common in the rest of the world. In this iteration the Rocna and a few other international brands were added to the list of contenders, which were tested on a “loose and loamy sand” seabed. The assistance of the French SNSM (analogous to the British RNLI) was employed, and it was one of their boats tasked with the pull testing.

Voile selected a total of fourteen anchors, and in their write-up and analysis of results separated them into three groups: “plate” anchors (symmetrical flat fluke types), “light” anchors (aluminium), and “plow” anchors (asymmetrical types). This last misnomer – less than half of those in the “plow” group were actually plows – may be forgiven as the writers have avoided the apples-to-oranges comparisons of different types and materials seen all too often in other tests. In the other categories, the light aluminium Spade and Fortress turned in good linear pull results but both failed physically (“twisted”) under the stress of the veering test.

This write-up did not include several of the traditional types usually seen, particularly the CQR and Bruce. The CQR was tested but would not reliably set and was excluded from the final results. The genuine Bruce is no longer manufactured but Voile tried to test the “Ray”, a knock off version by Manson, which also would not set and was similarly excluded from the tabulated data.

Test design

This test does suffer from an unfortunate tendency amongst magazines to measure loads whilst dragging the anchors, the testers apparently apathetic toward the notion that the primary function of an anchor is instead to stay where it was set. John Knox’s article in Practical Boat Owner (overviewed below) is an excellent counter-example of measuring the right properties in the right manner, which other publications could benefit from following.

Nevertheless, drag data of this sort is informative because, if the anchor is to drag, it is important that it continues to provide as much resistance as possible whilst doing so. When pulled beyond its yield, a good anchor will remain properly embedded rather than suddenly releasing, and should continue to bury down to where firmer substrate may provide a more secure holding.

Additionally, figures for “skewed holding”, or veered pulls, were measured by Voile to add to their conclusions. This data increases credibility and relevance to the real world where a general purpose anchor must do much more than simply provide good holding power in simple linear pulls.

Overviewed here are only the results for the “plow” group of asymmetrical general purpose anchors.

Voile dragged their anchors at an increasing velocity, measuring resistance at speeds from 0.1 knots to 0.4 knots. The latter was the penultimate speed, supposed to represent a dragging vessel in high winds or tide, and it is the figures for this that are charted in dark red in the graph below.

The results of the veered pulls are charted in yellow. This data is not normalized or adjusted for the varying sizes of the anchors.

Voile Magazine May 2012, François-Xavier de Crécy, anchor test data

While the “0.4 knots” pull data is not directly representative of the actual static holding power of the anchors, together with the veered pulls these results give a reasonable picture of relative anchor performance.

Practical Boat Owner (John Knox) August 2011

Practical Boat Owner Anchors On Test August 2011

Scotsman Professor John Knox has a history of anchor testing, write-ups of which have appeared in Practical Boat Owner before. Introducing this article, he describes his experience tenuously anchored to a CQR in the Inner Hebrides during a storm in 1988, and how this led to the testing of anchor types in order to best appraise performance.

Knox examined eight different anchor types, with the addition of multiple sizes of a few. He used tidal pools on sand flats on the west coast of Scotland, using a custom rig to exactly control pull forces and speeds.

Anchors ranged from small 5 kg (11 lb) to medium 15 kg (33 lb) examples. Unlike the dump-and-pull technique frequently used in other tests, Knox used a carefully designed rig powered by a winch and purchase system with a slightly elastic line. The anchors were pulled with intermittent pauses, allowing the candidate to rest and settle according to the pull maintained by the elasticity of the “rode”. This provided a figure for what Knox labels SHF (“Static Holding Force”). This process was repeated until the figures for SHF had leveled off and were judged unlikely to increase with further pulling – this final plateau dictated the anchor’s recorded holding power.

This methodology provides graphs of the anchor’s intermittently recorded SHF figures over time during each set, the shapes of which are also of direct interest. A poor design will give fluctuating and unstable SHF numbers – or an anchor that sets poorly and with shallow depth will quickly hit its plateau, while a good performer will show a steady rise stabilizing only at a relatively high force level.

CQR and Rocna anchor pull graphs

Knox seems well aware of the various pitfalls of anchor testing, and has avoided many of them in this test. His pull figures were firstly normalized against the results for a particular anchor for each session, to account for variations specific to that day or seabed area. Consolidated results were then further analyzed on a weight-for-weight basis and presented as “efficiency” values. The smaller anchors of each type, where multiple weights were tested, were found to be less efficient that the larger versions; nonetheless the results are presented without further analysis.

The below chart shows both normalized holding power and the rated efficiency values.

Practical Boat Owner August 2011, John Knox, anchor test data

This weight-for-weight efficiency measure is a fair approach in principle but does favor anchors with reduced strength (thinner section profiles and the like resulting in lower weights for a larger fluke surface area). It also fails to account for manufacturing tolerances outputting a lighter or heavier sample for what is really the same nominal ‘size’. For example, the Rocna 15 tested is nominally 15 kg but measured by Knox at a conservative 16.2 kg, while its Spade S80 competitor with an equal listed mass was found to shortchange its owner at only 13.3 kg. These variances combine to favor the undersized anchor in results – unduly so, because while tolerances or wear of material on a used anchor may cause significant variation, the surface area of the fluke, which dictates performance, is not affected by these factors.

The below chart depicts the same data as above, but with the efficiency values re-calculated based on nominal sizes.

Practical Boat Owner August 2011, John Knox, anchor efficiencies by nominal size

Larger anchors may expect to gain higher efficiency ratings, and this is borne out in this test when two sizes of the same type are compared. This is most obvious in the small sizes selected; by simple virtue of size, 15 kg anchors may expect their fluke tips to find better quality substrates than their 4 or 6 kg little brothers which have to make do with only the very top layer of the seabed. More telling is when a smaller anchor is proven to be substantially more efficient than its larger competitor.

West Marine, SAIL , & Yachting Monthly 2006

West Marine anchor testing: the “Shana Rae”

The big American retail chain has conducted a number of anchor tests over the years, and 2006 saw it put together a series of trials on three different sand seabeds with no less than fourteen different anchor types. They used real world locations and a realistic rode make-up.

Brief summaries of the results were included in the 2007 and 2008 West Marine catalogs. Additionally, staff from magazines SAIL and Yachting Monthly were present and proceeded to publish their own write-ups of the testing. These write-ups were problematic with confused analyses of the data and outright contradiction of one another on a number of details, but SAIL provided a good overview of the results in a chart averaging holding power and peak resistance.

Anchors of approximately 15 kg (35 lb) were selected, mostly steel but unfortunately including a few with part or whole aluminium construction. The aluminium Fortress FX‑37 Danforth-type chosen is relatively large compared to the other anchors tested, a size that would weigh in at over 25 kg (55 lb) if its aluminium was swapped to steel. Aluminium is weaker than steel, especially when compared to high strength grades: no less than two Fortresses were damaged and put out of action during this testing.

The testers used a short 20′ (6 m) length of 5/16″ (8 mm) chain, coupled to 1″ (25 mm) nylon to make up the rest of the rode. Tests were conducted at scopes of 7:1, 5:1, and 3:1, by a suitably large motorboat permitted to run up a maximum force of 5,000 lb-force (2,270 kgf). Consistency and reliability of the contending anchors was measured by further varying the testing to cover three different locations with different variations on a theme of hard sand.

The ability of the anchors to deal with a variety of tough (hard to penetrate) bottoms was well examined in this test, and the results serve to show up magazine “tests” which do not conduct repeat trials. Some anchors gave high peak results during some trials, but let themselves down during others. Consistency is a critical element of any anchor’s performance.

This table contains the summary comments published by West Marine themselves. Charted data results are below.

Averaged results

SAIL published the below chart, which graphs three different metrics if applicable for each anchor. “Max before releasing” is the only figure presented for all (except two anchors which failed to set): this is the most important, averaged “holding power” or static resistance. “Max pull” is the peak resistance measured by the testers, either static (holding) or dynamic (dragging) – this figure should be higher than “Max before releasing”, as a good anchor will give increasing resistance as it is dragged beyond yield. The absence of this figure, where it was lower than the static holding power, does not tell a pleasant tale for that type.

SAIL Anchor Testing Analysis: Average of Peak Strain at All Locations

The above chart makes no analysis of efficiency on a weight-for-weight basis, and there is a lot of variance in size between the anchors tested. If the same data is weighted for anchor size then ranked in order of increasing “Max before releasing”, the picture looks like this:

West Marine & SAIL magazine anchor comparison testing, test of 14 boat anchors

Lastly, the magazines can be ignored, and the raw data released by West Marine may be analyzed directly. This chart shows the averaged “holding power” of all test pulls, a few of which were apparently ignored by the magazines. Only the original numbers are used (unweighted).

West Marine & SAIL magazine anchor comparison testing, test of 14 boat anchors

  • “Holding Power” Bill Springer, SAIL October 2006
  • “Ultimate Holding Power” Toby Hodges and Bill Springer, Yachting Monthly December 2006
  • “Anchor and Docking / The West Advisor”, West Marine Annual Catalog 2007–2008
  • “Anchors Aware! Anchors On Test” Professor John Knox Practical Boat Owner August 2011
  • « 14 ancres sous haute tension » François-Xavier de Crécy, Voile Magazine May 2012
  • ”Ankkurit Testissä” Klaus Salkola Kippari March 2015
  • About the Manson Supreme Anchor , a Rocna look-alike – or why to avoid copies

More reading

  • A Process of Evolution: New Generation Anchors
  • Old Generation Anchors – What’s really the problem?
  • Catenary & Scope In Anchor Rode: Anchor systems for small boats
  • Anchor Rode Kellets – Uses and Applications
  • Two to Tandem: Maximizing holding power with tandem anchoring
  • Anchor Certification, HHP/SHHP Classification, and Type Approval
  • Coastguard Handbook: Anchoring Beyond 2007
  • New Generation Anchors Explained
  • Rocna Anchors website
  • Rocna Knowledge Base

Tired of anchors? Take a tour of some of the world’s best destinations…

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How To Anchor

Advertisement

Take your time, don't overdo the engine, and let nature do most of the work.

Dropping anchor

In advance, work out silent communications between the spotter at the bow, and the helmsperson: When the spotter wants slow RPM, she raises one finger. More RPM, hand in circular motion. Neutral, hand up. Less RPM, hand palm down. Kill engine, fist. Develop your own hand signals, review them with crew, and stick to them. (Photo: Billy Black)

Now, let's go through the steps for how to drop the hook and make sure your anchor holds.

Avoid the Biggest Boat Anchoring Problem

Prepare For Anchoring

Before the anchor goes over the bow, make sure you have plenty of rode and that it's free of tangles and ready to run. Anchor rode that you've already marked with the length helps you determine how much to put out. A length of chain helps weigh the rode down at the anchor, ensuring better holding. When you're ready to set, the boat should be motionless, or drifting very slowly astern. Any forward motion may knock the anchor against the boat's stem. This is especially true on boats with a plumb (vertical) bow. Forward motion can also cause the boat to run over the rode, possibly setting the anchor in the wrong direction and also fouling keel, rudder, and prop.

Penny Rode Markers

Measure your anchor rode, then, in some easy-to-remember pattern, attach zip ties through a chain link or to one strand of three-strand line. My system is one tie at 25 feet, two at 50 feet, three at 75 feet, and four at 100 feet. Then I just repeat the pattern, one tie at 125 feet, and so on. Some other progression might work better for you. The only takeaway here is that you must mark your rode in some manner, and zip ties do the job perfectly for just a penny each.

— Don Casey

Drop The Hook

Pick a spot to drop anchor, keeping in mind where you want the boat to end up and that the anchor will drag a short distance before it sets. As the boat drifts back, lower the anchor to the bottom, then gently pay out the rode. This will prevent the chain from piling up in a heap. If the anchor and rode all pay out in one line, free of tangles, everything should be ready to set it securely in the bottom. Take a turn around a cleat, if using a rode, and snub it off every now and then to take the pressure off your windlass and to let the tackle straighten out on the bottom.

Which One Is Best?

Results of a head-to-head anchor test.

Several years ago, Fortress Marine Anchors sponsored an in-water test of 11 different anchors to determine the holding power of each in a typical soft mud bottom. The test vessel was a position-stabilized research vessel from the University of Maryland Center for Environmental Science. Here are test takeaways:

  • The anchors that set the quickest and hardest were usually the ones with the sharpest flukes.
  • Few anchors exceeded 700 pounds of holding power, the American Boat and Yacht Council's calculated load in high winds for a 30-foot boat; 5 of the 11 anchors only reached 700 pounds once.
  • The Danforth and Fortress with their long, wide flukes outperformed the claw and plow anchors in holding power in soft mud.
  • "New generation" anchors performed no better than older designs.
  • Mantus and ULTRA were the only new-gen anchors that exceeded 700 pounds of tension on three of five sets.
  • The Fortress FX-37 at the 45-degree fluke angle was the overall holding power winner with three sets holding over 1,000 pounds and two sets exceeding 2,000 pounds.
  • Like real life, most anchors had one good set that far exceeded the rest. Almost all had one trial where the anchor didn't seem to engage the bottom at all, reinforcing the need to take your time when anchoring, letting the anchor settle before backing down on it.
  • It took between 10 and 20 feet of dragging for most anchors to reach 300 pounds of holding power, a bare minimum to consider for an anchor of this size.

— Charles Fort

Pay Out Proper Scope

Your anchor holds best when the load on it is horizontal, not vertical. So let out enough scope to accomplish that. First, add the depth of the water to the height of the bow from the water, then multiply that by 5 and pay out that amount of rode for a "lunch hook" when you'll be aboard, awake, and watching in calm conditions. If the tide is coming in, adjust for it so you rest at 5-to-1 scope once it's fully in. If it's windy or you might go ashore for a bit, pay out at least a 7-to-1 scope. If you're spending the night on the hook, pay out an 8-to-1 scope. NOTE: When you calculate scope, don't include the chain at the anchor end of the rode unless there's more than 6 feet or so; the chain's job is simply to weigh down the anchor.

Anchor scope chain rode illustration

Depending on the wind strength and length of time at anchor here are appropriate scope recommendations for a mixed rope/chain rode. For larger boats or for anchoring overnight, two to four boat lengths of chain attached to your rode is ideal.

So, for example, if you're anchoring in water that's 10 feet deep and your bow is 5 feet above the waterline, water depth (10) + bow height (5) = 15 feet, which means that for a lunch hook you should put out 75 feet of rode (15 feet x 5).

For an overnight stop in the same location, put out 120 feet (15 feet x 8), and so on. Some circumstances such as bottom type or expectation of a storm may call for more rode. But always make sure to stay clear of any boat or obstruction down wind or current.

Chain Rode Vs. Line

Chain is far more durable if you happen to anchor in bits of coral, rock, or debris. Also, chain will dig into mud or soft sand, helping the anchor. It forms a catenary, or curve, in the rode helping to keep the pull on the anchor horizontal so it digs in when under tension. An all-chain rode has some catenary in all but the strongest (i.e., hurricane) winds.

Anchor chain

Photo: Getty Images/gvm61

Catenary comes from weight, but unfortunately, weight is often the last thing you want aboard, and too much of it in the bow can adversely affect a boat's handling. Unless you have a larger boat, or you're going cruising, an optimal rode is composed of a length of relatively heavy chafe-resistant chain attached to the anchor, then a lightweight, strong, stretchy line attached to the chain — the best of both worlds.

Nylon line gets its shock-absorbing properties from stretch rather than through catenary action, and it's this property, along with its lighter weight and strength, that makes it a good rode. Three-strand nylon line has the most stretch. Polyester line is about 15% stronger and more resistant to chafe but doesn't absorb shock as well. Avoid using polypropylene line for this reason.

One to two boat lengths of chain is sufficient for most purposes, although more is always better. Be aware that with a rope/chain rode, only certain windlasses can bring in rope and chain on the same gypsy. Those that can will require that you use a rope-to-chain splice, which can be more vulnerable to chafe when not maintained/checked seasonally.

To create an effective rode, use good quality shackles to tie the system together, and mouse the pin to prevent it from unscrewing at a bad time.

— Bob Adriance

Set The Hook

Once you've let out ample scope, let the boat settle back on the anchor to straighten out the rode. A gentle breeze or a mild current may be sufficient for this step. If not, use the engine with just a touch of reverse. Pause and take a good look around, especially abeam (opposite the boat's middle), and note your position relative to other fixed objects.

Now, put the engine in SLOW reverse. You can expect to move slightly astern as the anchor and rode set themselves and stretch out. Soon, though, the boat should settle in a fixed position. If at this stage the boat is still moving astern, your anchor may be dragging; pick it up and dragging; pick it up and drop it again, perhaps in a different spot. If the boat's position is fixed, you should see prop wash alongside aft, and your anchor rode should be straight and taut.

To thoroughly set the anchor, with the engine still in reverse, increase the rpm. If the boat stays put, you can rest (relatively) easy, knowing you're hooked. Check your swinging room again, assuming that the wind or current might come from any direction.

How To Rig A Snubber

An anchor snubber, or snubbing line, performs two important functions for boats using all-chain rode: absorbing shock loads to an anchor rode and preventing the anchor windlass from taking all the strain as the boat swings at anchor and rises and falls with waves.

Snubber illustration

Notice how all the strain is taken by the snubbing line. The anchor chain is slack between where the snubber attaches and the windlass.

Anchor snubber line illlustration

The simplest way to rig a snubber is, after setting the hook, attach a 20-foot length of nylon line (ideal because it stretches) to the chain or rode using a rolling hitch, before you deploy the final length of chain. (Lengths may vary depending on your circumstances.) Attach the other end of the subbing line to a strong bow cleat, then feed out more anchor chain/rode until it hangs loosely between the rolling hitch and the windlass or other point where it attaches to the boat.

When rigged correctly, all the weight is taken by the snubbing line, not the windlass. Also, letting your chain loop down between the rolling hitch and cleat will add additional weight, thus producing more catenary effect which may improve the holding power of the anchor and give additional shock absorption to the rode.

To make rigging a snubber even quicker, many boaters with all-chain rode invest in a snubbing hook or chain hook. Both come in different sizes to suit the size of your chain and can be permanently spliced into the end of a suitable snubbing line. Once you're successfully anchored, slip the specially shaped hook over a chain link, attach the other end of the snubber to the boat, then let out a bit more chain until the snubber is taut.

— Mark Corke

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Contributing Editor, BoatUS Magazine

BoatUS Contributing Editor Tim Murphy is the author of "Adventurous Use of the Sea" (Seapoint Books, Nov 2022). He sails Billy Pilgrim, a 1988 Passport 40, on the U.S. East Coast. He develops marine trades curriculum for the American Boat & Yacht Council.

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Top Anchors Tested

  • By John Page Williams
  • Updated: August 10, 2015

Top Anchors

Editor’s Note : Many factors will ­affect anchor selection. Some are boat related, including an anchor’s ability to stow or be deployed. Others relate to location and bottom composition, such as the ­anchor’s ability to set and to reset itself during a tide swing. Furthermore, in bottoms of varying composition, the performance of different anchors will vary. Performance will also vary if the components of the anchor rodes are different. This test compares anchor performance in the same location, with the same rode, and in a mud-clay bottom only.

Will the anchor hold? Good question. Your life might depend on your answer. In a constant quest to evaluate anchor-holding power for its own ­products and the competition, Fortress Marine Anchors set up a rigorous test of 12 comparably sized, premium-brand anchors in typical mud/clay bottom of the Chesapeake Bay at Solomons, Maryland. Brian Sheehan and several other Fortress executives invited a dozen boating journalists to participate and “keep the testing honest” by carefully analyzing the methods and results over four days. Chuck Hawley, former vice president of product testing at West Marine and a videographer, recorded comments on each test (available at fortressanchors.com ). Here’s what we found.

Methodology Testing order of the anchors was random. They ranged in weight from 21 to 46 pounds and were designed for cruising boats in the 35- to 40-foot length overall range. Our platform was the 81-foot research vessel Rachel Carson , owned and operated by the University of Maryland’s Chesapeake Biological Laboratory at Solomons. With its twin 1,205 hp MTU diesels driving Hamilton water jets, 30 hp bow thruster, ­research-grade GPS (accurate within 0.0003 degrees) position-keeping system and 20 hp hydraulic winch with stainless cable, the big boat proved excellent for anchor testing.

The Fortress staffers and Rachel Carson ‘s skipper, Capt. Mike Hulme, picked out a broad testing area of mud/clay bottom in 26 feet of water. At a specific point ( a datum ), the deck crew placed each anchor overboard, and Hulme set off along a specific compass course ( azimuth ). When the scope reached 5:1, he proceeded another 100 feet and engaged ­position-keeping, jets and thruster keeping the vessel on station. Then first mate Rob Nilsen wound the anchor back in for 10 minutes (100 feet) with the winch. A tensiometer set into the cable’s run measured the anchor’s resistance (holding power) in pounds, recording it continuously on several linked computers in the vessel’s lab room as the scope fell from 8.8:1 to 5:1. Then Hulme backed over the anchor, and the deck crew retrieved it.

HOW TO BUILD AN ANCHOR RODE

For each pull, we watched the tensiometer plot resistance over time as the winch plowed an anchor through the bottom. Then we crowded around to look at its condition and the bottom material left on it. Chuck Hawley and the videographer recorded a summary after each pull. We writers scribbled notes. Afterward, Hulme returned Rachel Carson precisely to the datum, taking a different azimuth for the next anchor, to keep from plowing the same piece of bottom again and again. During four days, the crew tested each anchor five times.

The test protocol called for discarding fouled anchors in making the final judgment. Fate illustrated the wisdom of this provision on the first pull of the Fortress FX-37, when it broke free on long scope because, as we learned when it got back to the deck, it had picked up an oyster shell thick enough to jam between the flukes and the shank. The next day, another anchor picked up nylon line and a waterlogged stick.

The Right Stuff So what do we take away from all of this research? You need the right anchoring gear and the know-how and experience to safely and securely anchor your boat. Check out these seven essentials.

1. There is no such thing as “set it and forget it” with anchors. As in baseball, where every pitch counts, each anchor set brings its own challenges.

2. Even with all of the data available, anchoring remains a blend of science and seamanship.

3. Always remember: “Any anchor can fail to set the first time on any given day.”

4. Pay close attention to the specific area of bottom where you plan to set your anchor. Learn to read the sonar signatures of mud, sand, shell and combinations of those materials. As a backup, “fly the lead pigeon,” dropping a lead weight with a sticky substance like wax on it to pick up a bottom sample.

5. Think about all of the conditions that could affect the area where you propose to anchor, including depth, shoreline, other boats, “dragging room” and predicted wind.

6. If you, your family and your boat are going to depend on your anchoring systems for everything from a carefree lunch and a good night’s sleep to survival in a major storm, learn all you can about anchoring. There’s a lot of information out there ranging from the Anchoring Information tab on the Fortress website to the classic Chapman Piloting & Seamanship (67th Edition, 2013, $30 to $40 from amazon.com).

7. Finally, go boating. Put in your time on the water; learn from both your experiences and your conversations with other skippers; integrate all of it and put it to work for your boat, your family and yourself.

Anchor Test Results

Results The holding power curves for five pulls of each of the 12 anchors (including two for the Fortress FX-37, set at 32 and 45 ­degrees) are available for viewing at fortressanchors.com . You’ll note that Mike Hulme and the Fortress crew started at a new datum each day so that the anchors were worked through a fresh area of bottom.

It was impressive to see how much the results could vary from set to set with the same anchor in the same area. Every anchor failed to set initially at least once, and several broke free partway through because of either debris on the bottom or a change in the bottom’s composition.

During 54 pulls, the nine plow-type anchors held more than 1,000 pounds only twice. Their holding power peaked at scopes between 7:1 and 6:1. Several of the plow types showed reassuring consistency, helpful in a storm situation, where there is room to drag a little.

The highest holding power (more than 1,200 pounds) came from the fluke anchors, with the Fortress FX-37 set at 45 degrees (its soft-mud setting), peaking at 2,000 pounds. (At one point when it was in that range, the wake from a passing boat jostled Rachel ­Carson slightly, and the added force caused the breaker on the winch system to trip.) Note, though, that even that anchor delivered varying performance from pull to pull and within each pull.

TIPS FOR ANCHORING OVERNIGHT

We saw amazing variation in bottom consistency even in the relatively small area where we were working. I spent some time in Rachel Carson ‘s wheelhouse with Hulme, watching bottom signals on a Furuno FCV-585 sounder. The bottom hardness varied from firm clay to super soft, giving value to the protocol of averaging the results in ­judging each anchor’s performance.

Anchor Holding Power

Two Is Better Than One Always carry at least two anchors. Start with a main one whose rated holding power matches your boat’s length, beam and ­displacement. Add a lighter “lunch hook” for short stays and fishing. Having the lunch hook will also allow you to set both to hold a ­precise position, if necessary. Oh, and make sure you have a secure storage place aboard for each anchor before you buy it.

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Yachting World

  • Digital Edition

Yachting World cover

Drogues and sea anchors: we test a Jordan Series drogue and a ParaAnchor

  • Toby Hodges
  • September 3, 2015

Toby Hodges tries out a ParaAnchor sea anchor and a Jordan Series Drogue on a heavy weather sail training weekend in the English Channel

yacht test anker

Drogues and sea anchors are designed to slow a boat or allow it to hold station in extreme weather conditions. They can prevent a possible capsize, roll or broach by keeping the bow or stern facing the weather. Debates about the pros and cons are rife among cruisers.

In Skip Novak’s Storm Sailing Series he reveals that he isn’t in favour of streaming warps, let alone using a drogue or sea anchor. Yet there are numerous testimonials from long-distance sailors who place their faith in these devices.

Intrigued to see how practical this equipment is to use, I joined Rubicon 3, a sail training and exploration company, during a heavy weather sail training weekend. I was particularly keen to see how easy it is to deploy and retrieve a drogue or sea anchor, and compare their benefits.

We sailed from Portsmouth aboard the 60ft Hummingbird , an expedition yacht built for the original Clipper Race in 1996. We needed to sail 15nm offshore into the English Channel to reach a depth of 20m to set the sea anchor, which has a diameter of 26ft, and find enough sea room to retrieve the 110m drogue. Once these contraptions are deployed, the yacht’s ability to manoeuvre is limited.

60ft Hummingbird expedition yacht

60ft Hummingbird expedition yacht

Bruce Jacobs, together with Rachael Sprot, founded Rubicon 3 to offer a unique crossover of adventure sailing and sail training. They had requested we muster early in the morning so we could check and load the equipment. They ran through the theories of using drag devices and how we would deploy and recover them.

“The main thing you have to look for when in heavy weather is breaking seas,” said Jacobs. “The boat can handle breaking waves if they are in the right orientation – 20° each side of the bow and similarly to the stern. The thing you don’t want to do is end up sideways to the sea.”

Choices in heavy weather

Yachtsmen have the choice of battening down and riding out extreme weather by heaving-to, forereaching, or lying ahull. But these techniques will not prevent capsize if a yacht is hit by a breaking wave.

There are three choices of purpose-made tackle to help keep a yacht stable in big seas: a single drogue towed off the stern to stop it surfing, a series drogue (a series of multiple miniature drag devices or cones on one line) or a sea anchor. The latter two are bulky, expensive items to ship, but are proven to keep a yacht bow or stern to the waves.

Jacobs explained that it is easier to keep a yacht stern on to waves as it sits better to the wind and is stable running downwind under bare poles. The counter argument is that the bow has been designed to point into waves, whereas the stern can poop and take waves into the companionway. Both the theories and test accounts of using series drogue and sea anchors are wide ranging.

“Most importantly, if you can keep a fit and healthy crew, you can get around bad weather,” said Jacobs. “If you can keep the boat stationary, then the average storm will blow through in 24 to 36 hours. But most people go with it, which turns that into three to four days, with a tired crew.”

A Force 5 wind against tide produced enough chop to make life uncomfortable on board. It demonstrated how quickly crew can become ill or tired. As soon as we dropped the main, the motion changed for the worse and we struggled for balance as we prepared the drogues. “Even here, where conditions are not severe, the choppy sea has made half the crew feel seasick and want to retreat into their shell,” said Jacobs.

Para Anchor

OLYMPUS DIGITAL CAMERA

We trialled a ParaAnchor from Ocean Safety. The main towline is made from Nylon to keep elasticity in the system. A buoyed snag line improves retrieval and stops the anchor sinking. A parachute anchor has a huge surface area however, so its retrieval is not straightforward.

“We want the sea anchor to be on the same wave cycle as the boat, to rise and fall with the wave pattern,” said Bruce Jacobs, “otherwise you have huge snatch loads. So it’s worth keeping line in reserve so you can pay it out if you’re on a bad wave cycle.”

It is also worth double-checking the sea anchor is set up properly. Flaking out the line so it can run freely without snagging helps, but may not be practical. We paid out 100m of towline, which took up most of the side deck to flake. However, sea anchors are available with a deployment bag, which can simply be thrown into the water.

Para_anchor_global_12_kit_out_of_bag_laid_out

We rigged a bridle to help spread the load. Depending on hull(s) and keel shapes, the correct rigging of a bridle is an important factor in keeping a yacht head to wind. Ocean cruising veterans Lin and Larry Pardey advocate the use of a bridle with a scrap of sail to help prevent rolling. “Improvements may be found in leading it to an aft quarter cleat to allow you to trim it to an angle, or even putting up a scrap of main,” said Jacobs.

“One of the biggest causes of failure is chafe, so we also use a chain first to prevent this,” he added. The preparation and deployment of the ParaAnchor is time-consuming, but it certainly felt reassuring once in action. We drifted calmly, dead in the water, the motion instantly very much more comfortable.

The helm can be lashed and left once the anchor is set. A concern with sea anchors is that they can hold the bow too securely into oncoming waves, with the potential to shunt the boat astern. Allowing some flexibility in the helm lashing, by using a shock cord for example, provides a fuse to prevent rudder damage if this happens.

Para Anchor diag

Other worries with sea anchors are that they place a lot pressure on the bow fittings. Cleats may need reinforcing with backing plates. If not under pressure a sea anchor can sink and pull the bow down. Equally, too much pressure means it may rise up and break the surface, so monitoring is needed.

When in the trough of a wave the towline can go slack and the yacht may yaw away from the wind – the reason the US Coast Guard could not recommend a sea anchor deployed from the bow in its 1987 report .

Jordan Series Drogue

A series drogue comprises a multitude of fabric cones spliced in series onto a line with a weight on the end. The original series drogue was designed by Donald Jordan and it is trailed from the stern. The purpose of a series or ‘medium drag’ drogue is comparable to a sea anchor in that it is designed to hold the boat near-stationary – to prevent capsize in the event of a breaking wave.

OLYMPUS DIGITAL CAMERA

The number of cones is determined by the yacht’s displacement, but a typical Jordan Series Drogue (JSD) has between 100 and 200 cones of 5in (12.7cm) diameter attached to a tapered line. The load is spread across the multitude of cones, 172 in the case of Hummingbird ’s JSD.

“The danger with the wind behind is pitchpoling,” explained Jacobs. “The JSD will hold you back, stop you from surfing and prevent that happening.” The yacht is still able to accelerate down the face of a wave, but the JSD will slow it enough for the wave to pass through without dropping into a trough. The drag force is applied softly, allowing gentle acceleration until enough cones bite.

PW 5 tips Diagram 3

The potential to be pooped is an obvious concern. Can the cockpit drain quickly enough? The drogue’s inventor says crew should be below, as steering is not required. So the companionway hatch needs to be sufficiently watertight.

The JSD can flake neatly into a mesh deployment bag. A bight between each cone is attached to the bag, bridle to one end and chain weight to the other. Deployment is then just a case of setting up the bridle on winches and paying it out. We were aboard a robust yacht, but once again I could appreciate the need to make sure the attachment points for the bridle are reinforced.

Once the drogue was set, the motion changed immediately. We went from rolling and lurching to comfortably taking tea in the cockpit, making 4.4 knots SOG, but just 0.1 knot through the water.

Rachel Sprot with bridle and deployment bag, which keeps the drogue neatly flaked

Rachel Sprot with bridle and deployment bag, which keeps the drogue neatly flaked

If the ease of deployment is a benefit of the JSD, its retrieval is its downside. Jacobs says it can take over an hour. But a snag line can be used, and during our trials retrieval took approximately 20 minutes with the aid of a winch.

“You have to find a method that is comfortable for you and your boat – and this [JSD] obviously is for Hummingbird ,” said Jacobs. See also Jeanne Socrates’s article on those who have used a Jordan Series Drogue in anger

Conclusions

The trials demonstrated the value of preparation. Trying to sort out one of these drag devices, including the bridle and chafe gear needed, when the storm has already hit, would be daunting. So knowing how to set and use the equipment is key. It was also surprising to see how quickly a drogue or sea anchor can change the motion on board for the better, and the benefit this has on the mood and fatigue of the crew.

It is quite evident that, with practice, either could be a useful tool for riding out heavy weather. I remember setting a sea anchor during a Pacific delivery, for example, to stop the boat to cut a fishing net free from the stern gear. But during our trials with Rubicon 3, I found the series drogue easier to deploy and adjust than the sea anchor, with less to go wrong.

Prices and contacts For a 45ft yacht of 15 tonnes displacement:

  • Pacific 20 Para Anchor £1,829
  • Yacht Drogue (single) £395. Both from www.oceansafety.com
  • Jordan Series Drogue – 139 cones – £739 (Plus £82.40 for the bridle and deployment bag from £75) from www.oceanbrake.com

Also www.jordanseriesdrogue.com

See Skip Novak Storm Sailing Techniques Part 8 Drogues and Sea Anchors

Rubicon 3 – ‘sail’ ‘train’ ‘explore’

Rubicon 3 is owned and run by RYA Yachtmaster Ocean instructors Rachael Sprot and Bruce Jacobs. They bought Hummingbird two years ago.

Sally Splash - © Sally Golden Rubicon 3

“We wanted to do something different to what is already out there,” said Bruce Jacobs. “There is nothing really like what we do – you can typically only do adventure sailing or sail training, but this combines the two. It’s sailing with a purpose, sailing to get to great places.”

Their clients are typically aged between 35 and 60, around a quarter are new to sailing, and most sign up to sail on their own. The company has launched a series of Ocean Crossing Masterclasses. www.rubicon3.co.uk

Ausrüstung : Großer Anker-Test

Pascal Schürmann

 ·  02.08.2009

Ausrüstung: Großer Anker-Test

Vom Anker hängt unter Umständen jede Menge ab. Nicht nur ein im Zweifel viele tausend Euro teures Schiff, sondern auch das Wohl und Wehe der Crew. Die Crux dabei: Die entscheidenden Vorgänge spielen sich quasi im Verborgenen ab, nämlich unter Wasser.

Da ist es umso wichtiger, dass der Skipper dem Anker an Bord sozusagen blind vertrauen kann. Doch kann er das?

Der jüngst von uns durchgeführte Praxistest offenbart, dass Zweifel angebracht sind. Zwar preisen die Hersteller nicht selten die enormen Haltekräfte ihrer Produkte an, und dies meist auch noch auf allen Gründen. Doch die Realität sieht anders aus.

Da slippen manche Haken schon unter geringen Zuglasten, oder sie finden erst gar keinen Halt, graben sich nicht ein, schliddern rücklings über den Meeresboden.

Welche Anker in der Praxis als bordtauglich eingestuft werden können und welche allenfalls als zusätzlicher Ballast dienen, ist jetzt nachzulesen in der neuen Ausgabe der YACHT (Heft 17/09, ab Mittwoch am Kiosk).

Meistgelesen in der Rubrik Ausrüstung

yacht test anker

Is your anchor chain up the job?

Vyv Cox

  • November 6, 2020

It’s all well and good having a solid anchor, but having ground tackle that is going to keep you secure is equally important, says Vyv Cox

D47CGY_Alamy

The equipment used to anchor our boats is constantly developing as new materials and designs appear, equipment is adapted from other technologies or existing items are improved.

Old ideas are constantly questioned by rigorous testing and field experience.

Secure anchoring isn’t just about the anchor itself, however.

The whole rode that connects the anchor to the boat, made up of a number of different parts, is arguably at least as important, if not more so, than the specifics of the anchor.

If you get your ground tackle set up correctly, with an understanding of its abilities and limitations, you can be confident that the much-maligned ‘weakest link’, is not going to let you down in challenging conditions.

Anchor chain diagram

First, some clarification, what is meant by a rode?

A rode (more archaically called ‘cable’) is whatever comprises the connection between the anchor shank and the fixed point at the other end on the boat.

It is customary to refer to an all-chain rode or a mixed rode, meaning chain plus rope, but realistically the term also includes any component used to join any part of it together.

SHACKLE OR SWIVEL?

Many people will argue that there is no need for a swivel at all.

In many cases where there is no problem with the chain twisting, this is true and my own adage is to fit one if you find you need it but not otherwise.

My choice is to fit one because it makes turning the anchor after recovery so much easier, when inevitably it comes up the ‘wrong’ way around, and this may even be essential for some self-launching and recovering anchor systems.

Some chains twist naturally, perhaps due to uneven wear on adjacent links and some shapes of anchor rotate quite violently as they are being recovered.

shackle

Using a shackle between chain and anchor is simple and strong, as long as twisting isn’t an issue

If you find that your chain is regularly twisted on recovery, or becomes twisted in the locker, it may be that a swivel will help.

There are other solutions to anchors emerging the ‘wrong’ way, to be discussed shortly.

If opting to use only a shackle it’s wise to select one a size bigger than the chain.

The pin of a 10mm shackle will fit through an 8mm chain link and most modern anchors are slotted to allow the eye of a shackle to pass through it.

The same applies to a 12/10mm combination.

Shackles come in two basic shapes,:a ‘D’ and a bow.

Bow shackle

Bow shackles proved to be as strong as ‘D’ shackles

A ‘D’ would appear to offer better straight line strength but the bow would seem more able to cope with changes in pull direction.

The reality is that when I carried out destructive testing on both types there was no significant difference between either shape.

Chandlery-bought stainless steel shackles were generally stronger than their galvanised equivalents as shown in Table 1 below.

If we look at galvanised alloy steel shackles for the lifting and hoisting industries, however, we can see that those in the Crosby G209 A range, in Table 2 for example, are considerably stronger than any of the ‘marine’ offerings tested.

CMP, makers of the Rocna anchor, market another high strength shackle, the Titan Black Pin.

This make is marketed by some UK mail order chandleries.

Again, the strength offered by heat-treated alloy steel greatly exceeds the figures obtained from chandlery bought items, Table 3.

Strength

ANCHOR CONNECTORS

An answer to the problem of anchors recovered the ‘wrong’ way has been developed in Australia.

This is a simple asymmetric device called a Boomerang.

Gravity simply causes the anchor to rotate on the bow roller .

It is shackled to the anchor chain at one end and to a short length of chain between it and the anchor.

It therefore requires two shackles and an adequate distance between the bow roller and windlass.

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I tested a cranked swivel by Osculati working by the same principle but in my experience found it to inhibit setting of the anchor.

This may be due to the greater angular displacement offered by this device.

The marketplace offers a bewildering variety of swivels, ranging from roughly galvanised designs costing under £10 to beautifully engineered works of art in exotic materials costing well into three figures.

Connectors that are built down to a price will be fairly lightly built and will rely on two metal loops bolted together, as seen bottom right.

anchor-swivel

An anchor swivel will help eliminate twists, but the straight side arms can fail under lateral loading

This design is widely sold in chandleries and mail order outlets but any design that relies upon bolted components to carry the load of the chain or anchor is likely to have poor loading capacity and is best avoided.

In the destructive tests that I carried out the only swivels that had higher strength than the chain to which they were intended to connect were those in which the bolt simply held two forged parts together, the Osculati and the Kong.

In these the strength is provided by the forged construction, inherently strong and tough, as in the image below.

The only potential weakness would be if the connecting bolt were to undo, so I always use some thread lock on the swivel bolt.

This has proved to be totally reliable over 10 years plus.

The type illustrated has the disadvantage that any angled loads to the end of the anchor tend to bend the parallel arms of the swivel, although the designs normally offer lateral loading capacity equivalent to the SWL of the chain.

I devised a simple way to avoid the problem in 2007, reported in YM, and now widely used in anchoring advice.

Anchor-connector

Adding in three chain links between swivel and anchor retains the benefits, while allowing full articulation

This is the addition of two or three links of chain between the swivel and anchor, allowing total articulation.

More recently several manufacturers including Mantus and Ultra have introduced compact, expensive designs that allow articulation by eliminating side arms.

The top swivel shown above is by Mantus, using an incorporated bow shackle and forged pin to carry chain loads, while below it, the Ultra flip swivel uses two forged pins and utilises a ball joint that gives better articulation than parallel side arms up to about 45o-degrees of lateral displacement. Wasi make a similar swivel.

Were the anchor to be wedged in rock and the tide direction reversed, it could be imagined that high bending loads might be imposed upon the rather narrow necks, though the manufacturers claim breaking loads above that of chain.

Boomerang anchor rotator

A simple boomerang link will flip the anchor the right way up in recovery

Boomerang swivel

The Osculati twist anchor connector combines the boomerang idea with a swivel

ANCHOR CHAIN

As a rough guide to the right size chain for your boat, in 8mm Grade 30 chain is sufficient for boats up to about 37ft, 10mm up to 45ft and 12mm above that, but the displacement of the boat is an additional factor.

There is also clearly a difference in the chain needed for weekend pottering and extended high-latitude cruising.

A good way to decide on chain size is to consult chandlery websites, where good information is available.

Chain failure is very rare, thanks to a typical safety factor of 4:1.

The length of chain needed is also very much location dependent.

Cruising the Irish Sea I carried little more than 50 metres but for more sustained cruising I have extended that and now carry 65 metres.

Some areas further afield are blessed with deeper water anchorages for which lengths of up to 100 metres may be desirable.

0029_Kraken-50-DH

A well-drained chain locker will prolong the chain’s life

007_Anchor-connector

Chain is heavy

A yacht intending to cruise extensively might well carry 100 metres, amounting to 140kg for 8mm, 230kg for 10mm, stowed well forward where sailing performance would benefit least.

By substituting a smaller size but a higher grade some useful weight-saving is gained.

As an example, by reference to Table 4, carrying 100 metres of 8mm, Grade 70 instead of the same length in 10mm Grade 30 would save 90kg in the anchor locker and almost double the strength of the rode, from 4,800 to 8,400kg.

Marine chain in sizes up to 12mm is dominated by Chinese production, although one or two European manufacturers continue to produce.

The main UK importers of galvanised chain are probably Bainbridge and William Hackett.

The chain is nominally Grade 30 but testing has shown UTS figures to approach or even exceed the values required of Grade 40.

Many manufacturers reduce the thickness of zinc on production chain, with the result that many purchasers see rust after only two or three seasons.

AISI 316 stainless steel chain is normally to Grade 30 specification.

It is almost rust-free and its smooth finish does not heap in the locker, but it costs roughly four times that of galvanised chain.

Higher grades of stainless steel, 318L in Grades 50 and 60, are known as Cromox.

They have double the strength of 316 chain and considerably better corrosion resistance.

Chain in this material does not come cheap.

Strengths of chain grades

The Mantus (pictured above) and Ultra (below) are modern swivels that seek to eliminate earlier swivels’ weaknesses

ULTRA SWIVEL

The chief advantage of a mixed rode is weight saving, desirable in smaller or lighter yachts and particularly in catamarans.

Rope for mixed rodes may be three-strand or octoplait, either of which can be spliced to the chain if it is required to pass through a windlass.

Instructions for doing this are widely available on the internet but it will be necessary to consult the windlass manual to determine the precise type of splice that will pass through the gypsy.

Nylon is probably the most widely used material for this duty but polyester is also employed, nylon having rather more elasticity, especially in three-strand form, although nylon three-strand goes quite hard and inflexible after some time, not a desirable property in an anchor rode.

Octoplait seems to retain its flexibility to a greater extent.

Elasticity is very desirable in the rode, provided by a snubber in an all-chain rode but inherent in a mixed rode.

A medium-term problem with splices is that the rope remains wet for long periods, causing premature corrosion of the chain.

Regular inspection and fresh water washing is advisable.

For boats without a windlass, or for kedge use, it may be more convenient to splice a thimble into the end of the rope for attachment to the chain with a shackle.

A typical mixed rode will have about 30 metres of chain and maybe 50 metres of rope.

For most anchoring in moderate tidal ranges only the chain will be used, avoiding the difficulties that sometimes occur feeding rope into the chain locker, or worse, down a spurling pipe.

EXTENDING CHAIN

It is sometimes necessary to join two or more lengths of chain that are required to pass through a windlass.

This might be because it has been decided to carry a longer chain due to changing cruising grounds, or just because some corroded links need to be cut out.

The only way to do this is with a C-link.

This clever little device comprises two halves of a chain link that can be riveted together to form a single link.

When made up, and in the same material as the chain, a C-link has about half the strength of the mild steel chain that it is intended to join.

An eye splice

An eye splice is simpler, and can be connected via a shackle

A chain splice

A chain splice will allow the join to pass through a windlass

rusty-anchor-chain-link

Chain stored with wet rope can rust more quickly

For this reason a top quality C-link is made from heat-treated alloy steel that is about twice as strong as mild steel.

The result is a link that is as strong, or more usually stronger, than the chain.

It is an unfortunate truth that the vast majority of C-links sold in chandleries are made from mild steel, or possibly stainless steel.

These will have 50 to 60% of the chain strength when well made up.

Once again we turn to the lifting and hoisting industry where we find alloy steel C-links that will not compromise the strength of our chain.

Crosby also supply these, known as the G335 ‘Missing Link’, in Table 5.

Due to the fact that they are hardened and tempered, it takes some serious effort to peen the rivets.

A large hammer and drift on an anvil is the recommended technique.

Chain

ATTACHMENT TO THE BOAT

It would be remiss not to mention attachment of your anchor rode’s bitter end to the boat.

Should you pay out too much chain or should the windlass fail without doing so could easily result in the loss of your ground tackle.

Do not, however, shackle your chain to the boat.

If the anchor becomes fouled, or you need to let go the anchor in an emergency, you need to be able to let it go under load, and the only reliable way of doing this is by lashing the end of the chain to a dead-eye in the anchor locker, so that it can be cut in a hurry, or untied and attached to a large fender, should you need to let go the chain.

It’s also worth inspecting the dead-eye itself: is it big enough fitting?

Is the bulkhead it is bolted into in good condition, and does it have something to spread the load on the other side?

RECOMMENDATIONS

Anchor attachment

The rode’s bitter end should be securely attached to a solid point in the locker, but must be easy to let go in an emergency

C-links

C-Links are used to join chain. The two halves are placed together and the rivet peened inside the hole with a hammer and drift until fully secure

CROSBY G335 MISSING LINK STRENGTH

Modern anchors offer great improvements in holding power compared to those of yesteryear.

The rode that attaches them to the boat should also be of good quality.

Nominal Grade 30 chain is probably the most widely used and is generally totally reliable but, if the boat size is marginal for the recommended size, increasing the grade provides greater strength without the expense of a windlass gypsy change.

Grades 40 and 70 offer strength increases while Cromox gives the additional corrosion resistance.

Swivels should be types that do not rely on bolts to carry anchoring loads, whether on the anchor or the chain attachment.

Only use a swivel if you find it useful as they are not essential and can introduce weakness to the rode.

Galvanised alloy steel shackles from the lifting industry provide the greatest strength.

Wichard HR shackles (17/4 PH) were the strongest stainless steel shackles in testing.

Nylon rope has greater elasticity than polyester and three-strand construction has more elasticity than octoplait.

Nylon octoplait is a good compromise.

Alloy steel C-links from the lifting industry are as strong as Grade 30 chain but not advised for higher grades.

Mild steel and 316 stainless steel C-links have about half the strength of Grade 30 chain.

Vyv-Cox-photo

About the author

Vyv Cox is a retired metallurgist and engineer who normally spends six months of the year on board his Sadler 34 in the Mediterranean

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Classic Sailboats

Johan Anker VARG – Rebuilding a Legend

Archive – In 1924, the Norwegian industrialist Fritjof Larsen, commissioned the celebrated naval architect Johan Anker to design and build an eight metre yacht fast enough to beat the best of the British boats on the Solent. Anker “the Master of Lines” responded by creating the beautifully proportioned long and slender sloop that was to be called Varg (the Norwegian word for wolf), a vessel destined to have not one but two lives.

Varg’s success in English waters brought her to the attention of music publisher Frank Albert in faraway Australia and in 1926 he bought her as a 21st birthday gift for his son Alexis and had her shipped out to Sydney.

The Albert family didn’t much care for the name Varg so they chose to call her Norn, a reference to the all-powerful maidens in Norse mythology who rule the destiny of the gods and men. Norn was to become one of Australia’s most celebrated racing yachts. The winner of the coveted Sayonara Cup, she reigned supreme at Royal Sydney Yacht Squadron for almost half a century.

When the Albert family sold her in the 1960s she fell into a sharp decline and in the hands of a succession of indifferent owners, her classic lines were mutilated by a series of ugly accretions: a hideous cabin aft and the brutal truncation of her long and graceful counter stern. Sheathed in a crude skin of plywood she became a parody of a boat, a decrepit rotting hulk too weak to leave her mooring.

To hide her shame she slid to the bottom of Sydney Harbour where she remained for weeks until she was salvaged and again put up for sale. There were plenty of dreamers, but no one with an imagination vivid enough to perceive anything other than an old boat in the terminal stages of decay.

It would take the sensitive eye of an artist, a man with a profound aesthetic sensibility, to appreciate that lying beyond all that debris was in fact a rare and beautiful example of the work of one of the world’s most famous and gifted yacht designers.

That person was Kraig Carlström, a life-long racing sailor who also happens to be one of Australia’s most gifted professional photographers. Carlström understood at once that here was an exceptionally beautiful vessel and that he would be her saviour.

Even so, he was in for a dreadful shock as soon as he stepped aboard. There was well over a metre of putrid water in the bilge and she was streaked with rust and redolent of the sour smell of rotting timber. Although most of us would have turned tail and fled, Carlström held his nerve and stumped up the $25,000 her cheeky owner was asking. The price was to be subject to inspection by a qualified marine surveyor.

Carlström had the good sense to engage the services of Doug Brooker, then one of Australia’s best-known and most respected wooden boat builders. In the several hours they spent examining all the defects, the boatbuilder produced a penknife and deftly thrust it into her timbers, demonstrating that she was little more than a waterlogged sponge held together by the tens of thousands of staples in her plywood sheathing.

Carlström reluctantly asked for his money back. But, after a couple of restless months in which he found himself unable to shake off Varg’s memory, he decided to go back and offer roughly half the initial asking price. With no one else even remotely interested, Carlström found himself the owner of one very shaky old boat.

He knew that restoration was out of the question so he decided to truck the hull all the way south to his home at Cygnet, a sleepy backwater at the head of Tasmania’s beautiful D’Entrecasteaux Channel.

There, just a mile from his waterfront home, stands the rambling old tin shed at the heart of the famous Wilson Brothers boatyard. Since the 1870s four generations of the Wilson family have produced some of Australia’s most talented wooden boat builders, craftsmen who created many of the island state’s most famous trading ketches and schooners.

Michael Wilson and his very talented boatbuilding partner, Warren Innes, were then just completing a 47ft Herreshoff ketch. Carlström sounded them out. If the restoration of Varg was out of the question, might they consider taking her lines off and building an exact copy? After a prolonged pause came the answer … “yes, we could do that.”

It was a response that was to trigger one of the most ambitious boat building programs ever undertaken in Australia.

Carlström enlisted the help of the highly regarded Portuguese naval architect David Vieira who is one of the world’s leading authorities on eight metre class boats.

In the archives at Norway’s National Maritime Museum, Vieira unearthed Johan Anker’s original lines for Varg and subsequently produced a set of 23 drawings that would be needed for the boat. Nearly all the bronze deck fittings and winches were cast and finished in the specialist foundry associated with Vieira’s Absolute Restorations in Lisbon.

Varg’s magnificent Huon pine hull has been under construction for four years. She is a breathtaking example of the boat builder’s art. Rarely, if ever, has Australian boat building seen anything like the attention to detail that has been lavished on Varg. The timber selection has taken years and involves the use of only the very best and most beautiful Tasmanian native timbers.

When she goes in the water at the end of this year, Varg will undoubtedly be one of the most magnificent yachts ever constructed in Australia or anywhere else for that matter.

Kraig Carlström could have had her built anywhere in the world. How extraordinary therefore that he should have found craftsmen of the calibre of Michael Wilson and Warren Innes, just across the water from his own home on Port Cygnet Bay.

Varg’s original lead keel has been reused in the new boat. The old hull, which now serves as a piece of monumental sculpture, still draws admiring gasps from those who know and appreciate the work of the Master of Lines.

yacht test anker

This article, written by Bruce Stanard, was published in AFLOAT magazine September 2012 issue.

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Anchor Tests: Bending More Shanks

Exploring the effects of snatch loads on various anchor designs..

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Photos by Jonathan Neeves

In the first part of this series on anchor-shank strength ( PS , April 2013 ), we examined how the shanks of anchors that supposedly met the most stringent industry standards could theoretically bend under loads that a typical cruising sailboat could encounter. This month, we wanted to demonstrate how that might happen in a field test. But first, a recap.

In a nutshell, last months article explained how existing anchor tests are aimed primarily at commercial anchors, which have much thicker shanks than recreational anchors. We also lamented the fact that most anchor makers are not widely publicizing the details of materials and construction, and that they seldom offer useful performance criteria to help consumers make an informed purchase.

How can the shank of a supposedly high-tensile anchor bend? Our practical work on loading anchors ( PS, May 2012 ) indicated that a worst-case scenario is a sudden dynamic load, often called a snatch load, a short, sharp loading of a well-set anchor at 90 degrees to the set direction. We found that this type of snatch-loading can be caused by wind gusts and the sailboat yawing and/or sailing at anchor-even without waves.

Add wave action to the impact of a sudden veering wind, and we have perfect conditions to produce high dynamic side-loads on an anchor shank. PS contributor Joe Minicks graphic description of the freak storm that severely damaged his boat in Greece ( PS, April 2013 ) is a good example of the kind of severe, localized weather conditions that can impart extreme loads on an anchors shank.

Another instance when an anchor shank might be exceptionally loaded is on retrieval during strong winds or steep chop. Shortening scope during retrieval further compounds the problem. As pointed out in last months article, the difficulty in breaking out the modern, new generation anchors, poses another opportunity for a shank to bend during retrieval.

The angle of pull matters. Based on our anchor reset test (PS, February 2013), we know that when subjected to a series of gentle tugs at an angle to the set direction (up to about 150 degrees), most well-set modern anchors will slowly pivot around in the seabed. In that test, we noted that new anchors with convex, V-shaped sole designs like the Spade, Kobra, and Anchor Right Excel seemed to encourage pivoting. We also found that once most anchors are loaded at angles greater than 150 degrees, they will pull out, somersault, and reset.

Our tests on rode loads and anchor veering were preliminary fact-finding research, not comprehensive tests. This test is no different. Its principal purpose is to challenge the existing test methodologies and establish a pathway toward future testing.

Based on the findings in our previous work, we concentrated our study on a specific group of anchors and specific type of load. The anchors are regarded as super high holding power (SHHP) anchors-anchors that have demonstrated high holding capacity in a number of published tests. The load was a sudden, snatch (or dynamic) load applied at a 90-degree angle to the direction each anchor was set.

boat anchor shanks

unless otherwise noted

What We Tested

For this test, we narrowed the field to a cross-section of anchor types, in a size recommended for a 35- to 40-foot sailboat. The steel anchors weighed around 35 pounds, and the alloy anchors weighed about 18 pounds.

The anchors used were a 17.6-pound Fortress FX23, a Danforth-style anchor fabricated from a 6060 alloy aluminum; a 35.2-pound Spade anchor, a concave-plough design made of 316 stainless-steel (also available in aluminum and galvanized steel); a 19.8-pound Anchor Right Super SARCA, a convex plough design made from galvanized steel (350 megapascal); a 35.2-pound SARCA Excel, a convex plough design with mild steel fluke and a high-tensile steel (ASTM 514) shank; and finally a 17.6-pound prototype aluminum alloy (5083) SARCA Excel, with a thicker shank than the steel version.

Both Anchor Right and Spade offer anchors in different materials. For Spade, the choices are steel (ASTM A572GR50), stainless steel (316), and marine alloy (AG4 or 5083). Anchor Right uses the ASTM 514 in its steel Excel anchor and 2205 in the shank of its stainless-steel anchors. It is upgrading from 5083 to 6061 in its alloy anchors.

Of the materials used, 316 stainless steel has the lowest yield strength, followed by the aluminum alloys. The ASTM 514 galvanized steel is approximately 70-percent stronger than the 316 stainless steel.

We chose to test five ostensibly reliable anchors generally representative of the styles that are on the market. The anchors are of markedly different designs and materials, except that two of the anchors are identical in design but fabricated from different materials.

Why these anchors? First, we are familiar with these anchors. We have tested all five in a number of seabeds under varying conditions. Our tester has used an alloy Spade, the Excel, and Fortress as primary anchors for a number of extended cruises. All five anchors set exceptionally quickly, and all, when well set, can require some patience to break out.

Why no CQR? Why no Bruce? Why no Delta? Because of the time involved-not to mention the inherent variables of this test-we limited the test to designs that we suspected would have a higher rate of shank failure. In simple terms, we wanted deep-setting anchors with thin shanks. We wanted results. Our intention is to use this data as a baseline for future tests of shank strength in a more controlled setting. Once weve established the loads under which an anchor shank can bend in the field, we have a better picture of what loads to apply in the lab.

The basis of the tests was to try to simulate realistic conditions as closely as possible while still making it practical to carry out the test in a reasonable time frame. For more details on how the tests were carried out, see the accompanying How We Tested.

All of the test anchors pulled out under loads of about 4,500 pounds, except the Fortress, which pulled out at slightly over 3,000 pounds.

The shanks of all anchors, except the high-tensile SARCA Excel, were bent to varying degrees. Based on the results, the galvanized SARCA Excel, with its Bisalloy 80 shank, did very well, and we expect similar anchors that use the same shank material, such as the Manson Supreme, to do just as well.

How did they do? The accompanying photographs (see Testing Snapshot) tell the story:

Not only was the shank of the prototype 5083 alloy Excel bent, but the fluke also suffered severe distortion.

The shank of the Super SARCA was bent near the fluke.

The Fortress shank was mildly bent, near the middle of the shank. The Fortress flukes showed no sign of distortion.

The Spade shank was bent and twisted, and the shank slot in the fluke showed some minor distortion.

We ran more tests, including one on a 22-pound Excel anchor that has a steel shank with a yield strength of 350 megapascals (MPa)-commonly found in cheaper anchors. It bent as expected, further illustrating the value of a high-tensile steel shank. (It should be noted that this anchor was not designed for these loads, and that Anchor Right uses the higher-grade ASTM 514 in its larger anchors.)

boat anchor shanks

The Fortress fluke has a relatively low profile from the side and will have little, or low, resistance to a load at 90 degrees. It effectively cuts sideways in the seabed like a knife, and this might explain the lower load required to pull it out. An implication is that a Fortress will swivel with a change in wind direction much more easily than an anchor with higher-profile flukes that offer greater resistance to pivoting, such as a Supreme or Excel.

Although we do not know the precise load at which each shank bent, we do know that the Fortress shank bent at less than 3,000 pounds. Considering the limited amount of distortion, the shank looks to have bent close to the pull-out load. It seems the shank bent at or near where it emerged from the seabed when set-suggesting the seabed offers support to a shank. (More on this below.) Based on its own and independent tests, Fortress was confident that repeated tests and a deeper set would produce greater pull-out loads.

It was possible to straighten the Fortress shank for temporary use or for use as a spare, but we do not advise this as a permanent solution. This type of deformation, called plastic deformation, permanently weakens the metal. In this case, Fortress replaced the shank under its lifetime guarantee.

The failures of the SARCA and Spade shanks were not severe, suggesting they bent near the 4,500-pound pull-out load.

The severe and catastrophic failure of the alloy Excel suggest that it began bending well below the 4,500-pound maximum, although it still managed to sustain the same amount of load before releasing from the seabed as the steel Excel and stainless-steel Spade.

It would have been possible to straighten the SARCA shank for temporary use, but the complex bend in the Spade shank put it beyond repair.

Our experience with the Spade points to the advantage of a removable shank: The shank is typically an anchors weak point, but a removable shank can be easily replaced. Out of curiosity, we are considering replacing the bent hollow shank with one cut from -inch ASTM 514 steel-a material that has held up well in our testing.

The results indicate that there are two lever actions at work on most of these anchors-excluding the Fortress. There is a lever action parallel to the seabed, trying to re-orient the fluke to the direction of load. This lever action, best seen on the SARCA, stresses the horizontal axis of the shank. All anchors, except the galvanized high-tensile shank Excel, showed a degree of failure in the horizontal.

A second lever action loads the shank on the axis perpendicular to the seabed, effectively trying to twist or roll the anchor onto its side. Both the Spade and the experimental alloy Excel show distortion on this vertical axis.

The vertical portion of the SARCA shank has some support from its roll bar, and this might explain why we found no distortion of the vertical section. The Fortresss straight shank is stressed in one dimension only, having no vertical bend or L shape to its shank.

boat anchor shanks

Benefits of Burying

By comparing these field tests to the controlled, graduated loading tests that we carried out for the April 2013 article, it seems likely that a deeply buried shank will be less prone to bending. Last month, we demonstrated in lab testing that a 33-pound Excels half-inch ASTM 514 shank will start bending under a load of about 1,000 pounds if that load is oriented at 90 degrees to the shank.

This 1,000-pound failure is only about 25 percent of the load applied in our seabed test, which did not cause any failure to the same shank material. We partially attribute this discrepancy to the fact that the directions of load in the two separate tests were not identical; but it also seems likely that the seabed supports and reinforces the shank in the field test. In addition, our graduated load test in the lab applied the load for a much longer period than our seabed test, allowing more time for plastic deformation to take place.

If, as we suspect, the seabed offers support to a buried shank, then a poorly set anchor-an over-sized anchor, for example-might be more prone to shank failure than a well-set anchor with a deeply buried shank (assuming the shank dimensions are roughly equal). Likewise, an anchor with a weaker shank might better resist bending by virtue of its superior ability to bury itself.

The tests were too crude to present any accurate rankings, but it did reinforce our conviction that anchor shanks can bend in real-world circumstances-and that there is a clear difference in yield strengths. For the sake of reporting, the amount of bending, from none at all to severe, was the following: the galvanized Excel (ASTM 514), stainless-steel Spade, Super SARCA, Fortress, and aluminum-alloy Excel.

The results clearly illustrate the significant advantages of a well-engineered shank of high-tensile steel. The failure of the stainless-steel Spade also reinforces our point that using the same template for different material necessarily imparts variability in shank yield strength. (We would not have expected to see the same degree of a failure in the much stronger galvanized or even the aluminum version of the Spade, which has a beefed-up shank to account for the difference in tensile strength.)

Interestingly, even though the Super SARCA failed in our tests, it and the galvanized SARCA Excel (along with larger sizes of the Fortress) meet Classification Society (CS) requirements for holding capacity and for proof testing as super-high holding power anchors. Based on the Spades technical specifications, we would assume that its galvanized version, if tested, would also meet SHHP requirements.

Thus, our findings further support last months conclusion that the proof testing-as it is currently conducted-has limited value to the recreational marine industry, and that buying an anchor based on this stamp of approval might engender a false sense of security.

As mentioned, we think the problem of shank strength is most acute with those anchors that have super high holding power. The relentless pursuit of high holding capacity has produced better anchors, but unfortunately, there hasn’t been a commensurate increase in shank strength. There are better materials than the ones used in many of our tested anchors-ASTM 514, 6060 alloy, and 2205 stainless-and these should be an option. We have good design, now we need better material choice and fabrication.

Anchor Tests: Bending More Shanks

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Thanks for this! Very interesting and informative.

Just a note on terminology: All the anchors you test are alloy anchors. I realise that it’s possible to deduce what you mean when you say “alloy” by reading between the lines in your ninth paragraph. But if I find the article via a web search, or search for an item of interest such as “Excel”, your misuse of the word is a bit frustrating: any comment you make about “the alloy anchor” requires digging around to see how you have chosen to redefine it.

Minor quibble on the report. Great article overall.

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Rocna Anchors

IN THE FOOTSTEPS OF ROCNA

The vulcan is rocna’s first major design development since the launch of the highly successful and acclaimed rocna anchor itself..

Following on the success of the Rocna, designer Peter Smith was often approached by customers seeking to experience the exceptional holding power and setting performance of a Rocna, but who had difficulties accommodating the roll-bar design on their bow. After years of testing and development, Peter has come up with a design that meets the needs of these customers – the Vulcan.

Vulcan: An inheritance of genuine performance

The Vulcan capitalizes on finely tuned design elements from the Rocna pattern, infusing proven Rocna performance advantages for an extremely quick and reliable set across a range of seabeds combined with the expected Rocna holding power.

yacht test anker

NEW SOLUTIONS FOR OLD CHALLENGES: Breaking from the Rocna design, the Vulcan features a unique and patented shank and fluke geometry – including the innovative roll-palm™ (A) at the rear of the fluke – which self-rights the anchor on the seabed without the use of a roll-bar. This is assisted by the V-bulb™ (B) which extends fluke ballast downward to gain maximum leverage and efficiency. This development permits a larger fluke surface area than competing designs which rely on simple dead weight, while the concave fluke (C) is similar in design to the Rocna.

FIT FOR ALL VESSELS – AND THEIR OPERATORS: No roll-bar and a carefully designed shank profile (D) ensures a snug fit on the bows of a widely expanded range of vessels. Platforms, bowsprits, prods, stays, and other protrusions are cleared with less inconvenience.

SMOOTH BOW INTERACTION & COMPATIBILITY: The Vulcan’s shank shape (E) encourages self-launching and self-stowing upon retrieval on the majority of bow rollers, with a liquid smooth action, ensuring ease of use for all operators.

STRENGTH FROM SOPHISTICATED DESIGN: Working with high tensile steel, the Vulcan shank (E) is further strengthened by our patented I+V profile™ design. This computer optimized I-beam geometry brings higher resistance to bending, and further improves setting performance as the lower V-edge cuts into the seabed. This helps the anchor penetrate more easily to a deep and secure burial.

yacht test anker

IN THE IMAGE OF THE GODS: Embodying the rugged strength and elegant designs of its namesake – the ancient god of fire and metal smithery – the Vulcan shares the heritage of the Rocna anchor and is born of innovation.

TANDEM ANCHORING ATTACHMENT POINT: For extreme adventurers to extend their horizons even further.

SOLID STEEL: One-piece design for crew safety, ease of use, and simplicity of maintenance.

FINISH OPTIONS: Hot-dip galvanized coating for economical durability, or mirror-polished stainless steel for ultimate aesthetics and extended service life.

Vulcan Dimensions

Commonly requested measurements are tabulated below for anchors up to 55 kg (121 lb) at the orientation pictured. Using these drawings and a tape measure, many boaters can easily determine that a Vulcan anchor will fit their boat.

Click here to download full-scale patterns.

Vulcan dimensions drawing

Rocna Anchors Sizing Guidelines

There’s a Rocna anchor to suit just about any vessel. To choose the correctly sized Rocna Original or Vulcan anchor, find your vessel’s length from column on the left, then track across that row until you find the first column with a displacement (in tonnes) the same or larger than the displacement of your vessel. The top of the column with the selected displacement indicates the recommended Rocna Original or Vulcan.

For multihulls: use the chart as instructed, then select the model one size larger.

2023 Sizing chart card Rocna Original & Vulcan

Download Rocna Anchors Sizing and Dimensions Guide .

“We have a 65’ houseboat on Old Hickory Lake, part of the Cumberland River system. We typically boat with several friends with 70’ to 100’ houseboats. Most of these use a Fortress or Danforth-style anchor. Often we may have 6 to 8 boats tied together. Usually light wind and very little current. But that said, we almost always have to reset the anchor or anchors every weekend. Sometimes 2-3 times! So far, that has changed with my new Vulcan anchor. It sets instantly and holds!”

— paul barlar, vulcan 44 on a 65′ houseboat, anchor anxiety is a thing of the past.

Rocna anchors set fast and hold in all conditions, so you and your family or crew don’t have to be on constant tenterhooks. For the safety of your vessel, and everyone aboard, invest in the best anchor available. The anchor made by those who understand that when the storm hits, you need a rock solid anchor.

High Quality Build and Finish

A top performing product should be built like one, so the Rocna is manufactured with the highest standards of production and quality control to ensure a superior finished anchor.

Wide Competitively Priced Product Range

Available in 10 sizes from 4 kg (9 lb) to 55 kg (121 lb) to suit vessels from small runabouts to larger launches.

Guaranteed for Life

Each anchor comes with a Lifetime Warranty against manufacturing defects plus both breakage and bending.

FIT FOR YOUR VESSEL

Dimension drawings and full scale patterns are available here to evaluate fit dimensions.

SELECT YOUR SIZE

See our sizing guide for a Rocna anchor to suit just about any vessel.

You can find your Rocha anchor in most places globally. Contact us for remote locations.

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    Published boat anchor testing is generally of poor quality. Much of it amounts to nothing better than noise: terrible test designs, absence of controls, lack of repeat trials, and commercial or even nationalist biases generate unhelpful data that confuse and distract.

  5. Anchor Testing Summary. Anchor Video # 100

    How to Make Hard Kayak Out of Fine Plastic Powder. Awesome Korean Kayak Master Does the ULTRA Anchor Ring Stop your boat from swinging while anchored? The Aussie boat guy. Mantus Dinghy Anchor...

  6. How To Anchor

    Here are test takeaways: The anchors that set the quickest and hardest were usually the ones with the sharpest flukes. Few anchors exceeded 700 pounds of holding power, the American Boat and Yacht Council's calculated load in high winds for a 30-foot boat; 5 of the 11 anchors only reached 700 pounds once.

  7. Product Test: Heavyweight Cruising Anchors for Challenging Anchorages

    The Rocna comes in a range of weights, starting at 9 pounds. The 28-pound Rocna fared well in our 2006 test ("Soft Mud Anchors $200 and Up," April 2006). Rocna recommends about an 88-pound anchor for our test boat. The 121-pound Rocna Practical Sailor tested is rated for a 52- to 85-foot boat, depending on displacement.

  8. Ankertest: Auf die Grundhaltung kommt es an!

    Beim aufwändigen Test von sechs aktuellen Ankern in der Flensburger Förde konnte ein Taucher erstaunliche Ergebnisse zutage fördern. ... Der Anker zählt zu den wichtigsten Ausrüstungsgegenständen an Bord. Dass aber bei weitem nicht jeder hält, was er verspricht, bringt der große Ankertest ans Licht. ... YACHT CLASSIC BOOTE EXCLUSIV ...

  9. Top Anchors Tested

    The Fortress staffers and Rachel Carson's skipper, Capt. Mike Hulme, picked out a broad testing area of mud/clay bottom in 26 feet of water.At a specific point (a datum), the deck crew placed each anchor overboard, and Hulme set off along a specific compass course (azimuth).When the scope reached 5:1, he proceeded another 100 feet and engaged ­position-keeping, jets and thruster keeping the ...

  10. Tested: the new style Ultra Anchor

    Tested: the new style Ultra Anchor - Yachting Monthly Tested: the new style Ultra Anchor Theo Stocker June 1, 2020 0 shares Anchor design is always evolving and Ultra Marine claims its new design is the best yet. Theo Stocker tested the 12kg model, with the Ultra Flip Swivel, on his Sadler 29.

  11. Anchor Testing and Rode Loads

    Testing: Introduction For this test, we set out to establish what actual level of load is developed on the anchor of a boat at various scopes, from 3:1 up to 10:1, and various wind speeds, from five knots to 30 knots. The tests generated more questions, some of which we have tried to answer.

  12. Anchor Resetting Tests

    For this test, we included 12 different anchors: a 14-pound Ultra, a welded stainless-steel design made in Turkey and distributed in the U.S. by Quickline; a 12.5-pound Spade, a two-piece concave-fluke model made in Tunisia and distributed in the U.S. by Sea Tech and Fun; a 15-pound Super SARCA (Sand and Rock Combination Anchor), an Australian design with a prominent roll bar; an original, 20. ...

  13. Home

    The Rocna anchor was designed by New Zealand sailor Peter Smith, who has been designing, building, and sailing boats since the early 1960's. Crafted by seasoned sailor Peter Smith, Rocna anchors embody a legacy of nautical expertise and a passion for designing and building anchors, in addition to sailing. With a sailing journey spanning the ...

  14. How to Build Your Anchoring System

    Crucially, make sure it fits on your bow roller. Modern anchors typically fall into two camps—those with roll bars and those without. We've used a 33-kg Rocna on our Swan 48 Isbjorn (displacement 36,000 pounds) to great success since 2015, including two summers in Spitsbergen, one of the more challenging anchoring grounds in the world. The Rocna is a roll-bar style anchor and fits snugly ...

  15. We test a drogue and a sea anchor

    We needed to sail 15nm offshore into the English Channel to reach a depth of 20m to set the sea anchor, which has a diameter of 26ft, and find enough sea room to retrieve the 110m drogue. Once ...

  16. Ausrüstung: Großer Anker-Test

    Ausrüstung: Großer Anker-Test. ... Foto: YACHT/K. Andrews. Britany-Anker von Plastimo - allenfalls für den kurzen Badestopp geeignet. Hält er oder hält er nicht? Wie sich die neuesten Pflugschar- und Plattenanker auf unterschiedlichen Gründen bewähren ... ist jetzt nachzulesen in der neuen Ausgabe der YACHT (Heft 17/09, ab Mittwoch am ...

  17. Anchors & Anchoring: A Basic Guide

    This means when anchoring in 10M of water 30 M of chain should be paid out. With a rope rode this ratio would be 7:1, regardless of whether a short length of chain is used on the bottom. As depth in the anchorage increases so too should the ratio of anchor rode used. At 15M using a 5:1 ratio for chain is recommended.

  18. Is your anchor chain up the job?

    ANCHOR CHAIN. As a rough guide to the right size chain for your boat, in 8mm Grade 30 chain is sufficient for boats up to about 37ft, 10mm up to 45ft and 12mm above that, but the displacement of the boat is an additional factor. There is also clearly a difference in the chain needed for weekend pottering and extended high-latitude cruising.

  19. PDF Anchors: How We Tested

    They lined the anchors up on the top of the beach and pulled them toward the water with a windlass with a 6-degree angle for an effective scope of 10:1. Testers considered an anchor "set" once it would hold a 1,000-pound load. A second beachside pull test evaluated the anchors' ability with a 2:1 scope (32-degree angle) in sand and mud.

  20. Rocna Anchor testing and setting underwater

    Distant Shores TV 110K subscribers Subscribe 883 239K views 8 years ago Every wonder what an anchor looks like underwater when its setting? Here is a segment on setting the anchor in sand in the...

  21. Johan Anker VARG

    Archive - In 1924, the Norwegian industrialist Fritjof Larsen, commissioned the celebrated naval architect Johan Anker to design and build an eight metre yacht fast enough to beat the best of the British boats on the Solent. Anker "the Master of Lines" responded by creating the beautifully proportioned long and slender sloop that was to … Read more "Johan Anker VARG - Rebuilding a ...

  22. Anchor Tests: Bending More Shanks

    For this test, we narrowed the field to a cross-section of anchor types, in a size recommended for a 35- to 40-foot sailboat. The steel anchors weighed around 35 pounds, and the alloy anchors weighed about 18 pounds.

  23. Vulcan

    NEW SOLUTIONS FOR OLD CHALLENGES: Breaking from the Rocna design, the Vulcan features a unique and patented shank and fluke geometry - including the innovative roll-palm™ (A) at the rear of the fluke - which self-rights the anchor on the seabed without the use of a roll-bar.