AC-14 HHP Anchor — High Holding Power Bower Anchor

Why the AC-14 became the default

The AC-14 geometry puts a great deal more fluke area on the seabed for a given mass, with a wide crown that forces both flukes to trip together rather than letting the anchor lie on its side. That is what a holding-power trial actually measures, and it is why the pattern earns the mass reduction where earlier stockless designs do not.

For a shipowner the consequence is straightforward. A smaller anchor means a smaller hawse pipe, a smaller stowage recess, less hoisting effort and often a smaller windlass — for the same anchoring performance the class table asks for.

What “high holding power” actually requires

This is the part most commonly misstated, so it is worth setting out exactly:

• The anchor must hold with at least twice the holding power of an ordinary stockless anchor of the same mass.
• It must do so without prior adjustment or special placement on the sea bottom — no setting it by hand.
• Proof is by full-scale sea trials, three tests per anchor on each nature of bed, with the pull measured by dynamometer or from a tug’s bollard-pull curve, at a scope of about 10 and never less than 6.
• At least two anchor sizes must be tested, and the approval then extends only up to ten times the mass of the heaviest size actually tested.
• An approved anchor is then proof-tested at the load for 1.33 × its actual mass — a stiffer test than an ordinary stockless anchor of the same weight receives.

All of that attaches to a named design. It does not transfer to a similar-looking anchor from another source, which is why the type-approval certificate has to be produced and matched.

Super high holding power

A further class exists for anchors demonstrating at least four times the holding power of an ordinary stockless anchor, or twice that of an already-approved HHP anchor. It carries a 50 % mass reduction, but is restricted: generally to vessels of restricted service, generally to anchors up to about 1,500 kg, with trials on three specified bottom types — soft mud or silt, sand or gravel, and hard clay — and three anchor sizes. It is not a general-purpose alternative to the AC-14.