The Ultimate Chain Hook for Catmarans ... Revisted

rev. 9-13-2016, rev. 7-21-2024

The Problem. Catamarans use a long bridle, and monohulls should to, to reduce shock loading on the anchor and chain. Unfortunately, an ordinary chain hook falls off if it rests on the bottom in shallow water during light winds. The boat shifts around and the chain walks out. I've had this happen with every non-locking hook, including those that include some manner of labyrinth. There must be a lock in my opinion.

My first solution, not for sale anyplace I could locate, was a steel plate is 3/8" x 3" x 4 1/2" A-460. The left hole is 5/8" and generally holds a large stainless carabiner, the right hole is 3/8" and is a good fit for the 5/16" SS shackle that forms the pivot of the latch. The slot is 3/8-inch, over size to allow for an easy fit and because 1/4-inch chain is closer to 5/16-inch at the weld. The chain rode drops into the slot and can't get out once the second bridle line is attached. Very simple and idiot-proof in years of testing. The apex hole is 5/8" and also generally holds a 3/8" anchor shackle used to secure a sling that is Prusik hitched to a fiber rode.I don't use this feature and consider it a bad idea, since it is better to attach the second rode to the chain.

Calculations show that it should have a safe working load of 3200 pounds in any loading combination, including attaching only one bridle leg. I tested it to 5500 pounds on a test rig I once used for pulling rock climbing gear apart; there was no permanent distortion. My anchor chain is 1/4" G-4 and my governing working load is thus 2600 pounds.

But you can't buy it. However, since I introduced this eight years ago, there is now a nice hook on the market that you can buy....

A Possible Solution? But Not. The Mantus Chain Hook. 

I used this for about four years and found it very handy. It can be attached with one hand and a locking plastic plate keeps the chain in place. Unfortunately, it is difficult to operate with one hand in sizes over 1/4-inch. Also, the hook was tested and found to potentially weaken the chain because of the sharp V-edge at the bottom of the slot. That was a mistake. 

As long as the hook is used well below the WLL by using an elastic snubber, no problem. Personally, I moved back to using either the bridle plate (above), a soft shackle (seldom), or a Prusik hitch and a Dyneema sling (often).

Good Solutions. A friend in Australia made me one (he calls it a Barra) and had it ArmorGalv treated. Viking Anchors now make this commercially. Very nice. And the Ukraine can use your support. This would be my first choice.
 

The long shackle makes spinning the locking plate easier.

 Much stronger than the chain, can't come off, completely redundant attachments.

The One You Can Buy.

 The Viking Bridle Plate also allows rigging dirrectly with rope, giving some interesting possibilities. My choice. The funny milling in the groove helps the link rotate into a position where it is better supported. Mantus had this idea, but they didn't get it quite right.