Anchor Guide

 

Welcome to Stainless Directs Quick Anchor Guide. This Info page is designed to help you make the correct purchase of your Anchor and Anchor fittings. Along with all your other boat bits it is important you have the right Anchors on board.

 

 

What Size Anchor Should I Buy?

 

We get asked this question often.

 

Below are Quick reference Tables to help you quickly calculate the right size of Anchor and Anchor Chain to buy here at StainlessDirect. The Marine Superstore.

 

Boat Length (m)

Main Anchor (kg)

Kedge Anchor (kg)

Main Anchor Chain (mm)

Main Anchor Rope (mm)

Kedge Anchor Chain (mm)

Kedge Anchor Rope (mm)

6

8

4

6

12

6

10

7

9

4

8

12

6

10

8

10

5

8

12

6

10

9

11

5

8

12

6

10

10

13

6

8

12

6

10

11

15

7

8

12

6

10

12

18

9

8

14

8

12

13

21

10

10

14

8

12

14

24

12

10

14

8

12

15

27

13

10

N/A *

8

12

 

A good anchor system is your best insurance policy. The system will only be as good as the weakest link, therefore every element needs close scrutiny from the shackles to the Anchor itself. There is no anchor on the market that will be 100% effective on sea beds of all types so it is recomended that you carry a Kedge (secondary) anchor and warp in addition to your Bower (primary) anchor and warp. Typically the 2 anchors will be geometrically different so as to provide a different option should one be proving ineffective on any given seabed.

 

What Types of Anchors are available at StainlessDirect.co.uk?

 

Our most popular Anchors we sell are listed below, along with a brief History of the Anchor itself, the Anchor Design and Anchor characteristics.

 

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 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 difficult 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.

 

Plough/CQR Anchor

So named due to its resemblance to a traditional agricultural plough (or more specifically twoploughshares), 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) by mathematician Geoffrey Ingram Taylor. 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.

 

Crown Anchor / Fluke Anchor / Cruising 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 light weight 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.

The fluke anchor has difficulty penetrating kelp- and weed-covered bottoms, as well as rocky and particularly hard sand or clay bottoms. If there is much current, or 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

 

Bruce Anchor / Claw Anchor

This claw-shaped anchor was designed by Peter Bruce from the Isle of Man in the 1970s. 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 other types. On the other hand they perform relatively well with low rode scopes and set fairly reliably. They cannot be used with hawsepipes.

 

 

Fisherman Type Anchor / Admirallity Pattern Anchor



The Admiralty Pattern, "A.P.", or simply "Admiralty", and also known as "Fisherman", is the anchor shape most familiar to non-sailors. It consists of a central shank with a ring or shacklefor attaching the rode. At the other end of the shank there are two arms, carrying the flukes, while the stock is mounted to the other end, at ninety degrees to the arms. When the anchor lands on the bottom, it will generally fall over with the arms parallel to the seabed. As a strain comes onto the rode, the stock will dig into the bottom, canting the anchor until one of the flukes catches and digs into the bottom.

 

This basic design remained unchanged for centuries, with the most significant changes being to the overall proportions, and a move from stocks made of wood to iron stocks. Since one fluke always protrudes up from the set anchor, there is a great tendency of the rode to foul the anchor as the vessel swings due to wind or current shifts. When this happens, the anchor may be pulled out of the bottom, and in some cases may need to be hauled up to be re-set. In the mid-19th century, numerous modifications were attempted to alleviate these problems, as well as improve holding power, including one-armed mooring anchors. The most successful of these patent anchors, the Trotman Anchor, introduced a pivot where the arms join the shank, allowing the "idle" arm to fold against the shank.

 

Handling and storage of these anchors requires special equipment and procedures. Once the anchor is hauled up to the hawsepipe, the ring end is hoisted up to the end of a timber projecting from the bow known as the cathead. The crown of the anchor is then hauled up with a heavy tackle until one fluke can be hooked over the rail. This is known as "catting and fishing" the anchor. Before dropping the anchor, the fishing process is reversed, and the anchor is dropped from the end of the cathead.