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Small boat anchors Until the mid-20th century, anchors for smaller vessels were either scaled-down versions of admiralty anchors, or simple grapnels. As new designs with greater holding-power-to-weight ratios, a great variety of anchor designs has emerged. Many of these designs are still under patent, and other types are best known by their original trademarked names.

Grapnel anchor

A traditional design, the grapnel is merely a shank with four or more tines. It has a benefit in that, no matter how it reaches the bottom, one or more tines will be aimed to set. In coral, or rock, it is often able to set quickly by hooking into the structure, but may be more difficult to retrieve. A grapnel is often quite light, and may have additional uses as a tool to recover gear lost overboard. Its weight also makes it relatively easy to move and carry, however its shape is generally not very compact and it may be awkward to stow unless a collapsing model is used.

Grapnels rarely have enough fluke area to develop much hold in sand, clay, or mud. It is not unknown for the anchor to foul on its own rode, or to foul the tines with refuse from the bottom, preventing it from digging in. On the other hand, it is quite possible for this anchor to find such a good hook that, without a trip line from the crown, it is impossible to retrieve.

Herreshoff anchor

Designed by famous yacht designer L. Francis Herreshoff, this is essentially the same pattern as an admiralty anchor, albeit with small diamond shaped flukes or palms. The novelty of the design lay in the means by which it could be broken down into three pieces for stowage. In use, it still presents all the issues of the admiralty pattern anchor.

Northill anchor

Originally designed as a lightweight anchor for seaplanes, this design consists of two plow-like blades mounted to a shank, with a folding stock crossing through the crown of the anchor.

CQR (secure) plough anchor

CQR anchor

So named due to its resemblance to a traditional agricultural plough (or more specifically two ploughshares), many manufacturers produce a plough-style design, all based on or direct copies of the original CQR (Secure), a 1933 design patented in the UK (US patent in 1934<ref>us patent 1974933, G. I. Taylor, "Anchor", issued 1934-09-25 </ref>) by mathematician Geoffrey Ingram Taylor.<ref>{{#invoke:Citation/CS1|citation |CitationClass=journal }} Cited by {{#invoke:Citation/CS1|citation |CitationClass=journal }}</ref> Ploughs are popular with cruising sailors and other private boaters. They are generally good in all bottoms, but not exceptional in any. The CQR design has a hinged shank, allowing the anchor to turn with direction changes rather than breaking out, while other plough types have a rigid shank. Plough anchors are usually stowed in a roller at the bow.

Owing to the use of lead or other dedicated tip-weight, the plough is heavier than average for the amount of resistance developed, and may take more careful technique and a longer period to set thoroughly. It cannot be stored in a hawsepipe.

Delta anchor

The Delta was developed in the 1980s for commercialization by British marine manufacturer Simpson–Lawrence.

Danforth anchor

A fluke-style anchor

American Richard Danforth invented the Danforth pattern in the 1940s for use aboard landing craft. It uses a stock at the crown to which two large flat triangular flukes are attached. The stock is hinged so the flukes can orient toward the bottom (and on some designs may be adjusted for an optimal angle depending on the bottom type). Tripping palms at the crown act to tip the flukes into the seabed. The design is a burying variety, and once well set can develop high resistance. Its lightweight and compact flat design make it easy to retrieve and relatively easy to store; some anchor rollers and hawsepipes can accommodate a fluke-style anchor.

A Danforth will not usually penetrate or hold in gravel or weeds. In boulders and coral it may hold by acting as a hook. If there is much current, or if the vessel is moving while dropping the anchor, it may "kite" or "skate" over the bottom due to the large fluke area acting as a sail or wing. Once set, the anchor tends to break out and reset when the direction of force changes dramatically, such as with the changing tide, and on some occasions it might not reset but instead drag.<ref>{{#invoke:citation/CS1|citation |CitationClass=book }}</ref>

The FOB HP anchor, designed by Guy Royer in Brittany in the 1970s, is a Danforth variant designed to give increased holding through its use of rounded flukes setting at a 30° angle.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>http://offshore.ussailing.org/Assets/Offshore/SAS+Studies/1994+anchor+test.pdf</ref>

The Fortress is an aluminum alloy Danforth variant which was designed by American Don Hallerberg. This anchor can be disassembled for storage and it features an adjustable 32° and 45° shank/fluke angle to improve holding capability in common sea bottoms such as hard sand and soft mud.<ref>Hallerberg, Don, U.S. Patent 5,154,133 13 October 1992</ref> This anchor performed well in a 1989 US Naval Sea Systems Command (NAVSEA) test.<ref>Witherell, P.W.: ANCHOR TEST REPORT for NINE MOVABLE-FLUKE ANCHORS (31 pounds to 200 pounds) NAVSEA Rpt. No. 835-6269039, June 1989</ref> and in an August 2014 holding power test that was conducted in the soft mud bottoms of the Chesapeake Bay.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Bruce or claw anchor

Bruce anchor

This claw-shaped anchor was designed by Peter Bruce from the Isle of Man in the 1970s.<ref>Bruce, Peter, U.S. Patent 4,397,256 9 August 1983</ref> Bruce gained his early reputation from the production of large-scale commercial anchors for ships and fixed installations such as oil rigs. The Bruce and its copies, known generically as "claws", have become a popular option for small boaters. It was intended to address some of the problems of the only general-purpose option then available, the plough. Claw-types set quickly in most seabeds and although not an articulated design, they have the reputation of not breaking out with tide or wind changes, instead slowly turning in the bottom to align with the force.

Claw types have difficulty penetrating weedy bottoms and grass. They offer a fairly low holding-power-to-weight ratio and generally have to be oversized to compete with newer types.{{ safesubst:#invoke:Unsubst||date=__DATE__ |$B= {{#invoke:Category handler|main}}{{#invoke:Category handler|main}}[citation needed] }} On the other hand, they have a good reputation in boulder bottoms, perform relatively well with low rode scopes and set fairly reliably. They cannot be used with hawsepipes.

Recent designs

Rocna anchor

In recent years there has been something of a spurt in anchor design. Primarily designed to set very quickly, then generate high holding power, these anchors (mostly proprietary inventions still under patent) are finding homes with users of small to medium-sized vessels.

  • The German-designed bow anchor, Bügelanker (or Wasi), has a sharp tip for penetrating weed, and features a roll-bar which allows the correct setting attitude to be achieved without the need for extra weight to be inserted into the tip.<ref>Ginsberg-Klemmt, Erika & Achim, and Poiraud, Alain (2007) The Complete Anchoring Handbook, Ragged Mountain Press, ISBN 0-07-147508-7</ref>
  • The Bulwagga is a unique design featuring three flukes instead of the usual two. It has performed well in tests by independent sources such as American boating magazine Practical Sailor.<ref>Practical Sailor: "Anchor Reset Tests", Belvoir Pubs, January 2001</ref>
  • The Spade is a French design which has proved successful since 1996. It features a demountable shank (hollow in some instances) and the choice of galvanized steel, stainless steel, or aluminium construction, which means a lighter and more easily stowable anchor.<ref>Poiraud, Alain (2003) Tout savoir sur le mouillage, Loisirs Nautiques, ISBN 2-914423-46-2</ref>
  • The New Zealand–designed Rocna has been produced since 2004. It too features a sharp toe like the Bügel for penetrating weed and grass, sets quickly,<ref>Lowe, Colin: "Gear Test: Rocna Anchor", Boating NZ, July 2006</ref> and has a large fluke area. Its roll-bar is also similar to that of the Bügel.

Other temporary anchors

  • Mud weight: Consists of a blunt heavy weight, usually cast iron or cast lead, that will sink into the mud and resist lateral movement. Suitable only for very soft silt bottoms and in mild conditions. Sizes range between 5 and 20 kg for small craft. Various designs exist and many are home produced from lead or improvised with heavy objects. This is a very commonly used method on the Norfolk Broads in England.

Anchor sections
Intro  Overview   Evolution of the anchor    Small boat anchors    Permanent anchors    Anchoring gear   Anchor warps   Anchoring techniques   In heraldry  See also  References  Bibliography  Further reading  External links  

Small boat anchors
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