When researching Changing Views on Chain Hooks (see PS, March 2016 online), we were surprised to discover that some chain hooks greatly reduced the breaking strength of a chain. Unless the hook itself broke, we assumed its effect on chain strength would be very minor.
There are a number of ways to attach a snubber to an anchor chain. A gripping hitch, a soft-shackle, or a chain hook are the most common. Of the three, Practical Sailor has a strong preference for a camel hitch or similar gripping knot, but for the many who seek a faster, simpler way to attach a snubber, here is a look at chain hooks.
When it comes to snubber sizes and diameters, catamarans present special challenges, and usually require a bridle, with separate lines leading from the hook to each hull. Heres an example of the bridle-type snubber that PS contributor Jonathan Neeves uses on his seven-ton, 38-foot catamaran that he lives aboard and cruises in Australia.
During our research, nearly every maker of industrial chain offered the same caution: Using a generic chain hook can reduce the link strength by 20 to 25 percent. The generic style of chain hook, familiar to most sailors, resembles an elongated fish hook. As we found in this test, some other hook types are potentially more harmful.
Past articles and our recently published e-book on anchoring prompted a wide variety of questions from readers regarding anchor snubber length, material, and diameter. To answer these questions, PS contributor Drew Frye sought to create a simple formula for determining the correct sizing and material. The formula is not meant to be definitive, but part of ongoing work. Practical Sailor welcomes more input on this topic.
In our recent article on anchor swivels (see PS September 2015 online), we reiterated our view that swivels are unnecessary in most anchoring situations. For those who insist on using one, we suggested staying away from cheap varieties, and using only load-tested designs that exceed the rating of the anchor chain from every angle of pull. (None of the ones we have found that meet this criteria are cheap.) Shortly after that article, Mantus Anchors, a relatively new maker of anchors and anchoring accessories, introduced its swivel, which it claims is as strong as an ordinary shackle and priced in a range that ordinary cruisers can stomach.
We know the theory behind using anchor swivels: The swivel releases any twists in the chain when an anchored boat swings through 360 degrees or more. Still, we question the logic of using them. Our skepticism is supported by our own experience, previous testing, and input from long-term cruisers, but we wanted to devise a test to investigate chain twisting.
Sailors spend considerable time pondering their anchoring arsenal for the mothership, but what about the dinghy? With the new Mantus Dinghy Anchor, it seems that all of the design schools are now represented in small sizes. We were interested to determine which of these might offer the best performance.
Each anchor was pulled in both a straight line and at 90 degrees in both soft mud and firm sand at a 10:1 scope. All findings regarding load were recorded with a calibrated load cell. Testers performed the 90-degree test by lightly setting the anchor (with a 15-pound load in mud, 40 pounds in sand) and then slowly pulling at a 90-degree angle, as though the wind or tide changed. Additionally, each anchor was used day-in, day-out aboard an inflatable dinghy to evaluate ease of use and real-world effectiveness.
Stroll down the docks at any boat show, and youll see a surprising number of boats equipped with expensive, stainless-steel swivels between the anchor and the chain. Almost all of these swivels are highly polished, machined and/or welded gems that cost anywhere from $80 to $200 or more. By comparison, a galvanized anchor shackle rated to withstand the same or greater loads as the chain rode we rely on costs less than $15.