Ground Tackle Inspection Tips
Sometimes, the weakest elements of an anchor system are hidden in plain view.
Your anchoring system is only as strong as its weakest component, which includes not only the rode, but also shackles, splices, mooring bitts, cleats – in short, any gear used to secure your boat while at anchor. Proper maintenance includes inspection of these as well as laying the rode out for thorough examination at least annually.
Start by inspecting your anchor. Are there bent flukes or other such damage? If galvanized, is the coating in good shape or are there areas of rust and corrosion?
Next up is the anchor rode, which can be a combination of rope and chain or all chain.
For combination rodes, start by inspecting the rope-to-chain connection, which will be made via a rope-to-chain splice or by utilizing an eye splice and thimble (which in turn will be attached to the chain portion via an anchor shackle).
Direct splices should be tight and the link it connects to free of corrosion. Eye splices should have a minimum of six full tucks and be seized at each end while the eye is under tension (to prevent the thimble from falling out as the eye stretches when placed under load). Ensure all shackles are properly sized and that all screw pins are moused (secured) with stainless steel wire (a requirement for all chain rodes as well).
Check the rope portion of the rode for wear, hard spots (due to heat generated friction caused by placing a kinked line under load), cut strands, aging, discoloration, etc. Chafe is a rope rode’s worst enemy, so you’ll also want to check hawseholes, chocks, cleats, windlasses, etc, for burrs, sharp edges, protruding hardware, or anything else that can cause rode damage.
While chain is tougher than rope, it’s not maintenance free. Start by storing your chain clean and keeping it as dry as possible to reduce corrosion (and odor).
Avoid exposing your chain to preventable chafe, such as pulling your chain along that concrete dock while laying it out for inspection. Dragging your chain over abrasive surfaces removes the galvanized coating and eventually leads to rusting. Chain should be swapped end-for-end annually to promote even wear of the galvanized coating. Chain should be replaced or re-galvanized once rust begins to appear, however the latter should be done no more than twice, after which the chain should be replaced.
If you must temporarily join two shots of chain, common methods are the riveted connecting link, the double jaw midlink, and the quick-connect link (see PS Advisor, June 2018). A riveted link looks like any other link. If you use this type of link, make sure that it meets federal code, as well as the load limits for your chain. Crosby is one maker of such links—the G335 “Missing Link.”
For easier replacement, PS recommends high-strength, Omega and hammerlock links. These are used in the lifting industry. Choose G100 quality. You will need two omega links, but only one hammerlock. They are usually painted, not galvanized, although Peerless has a zinc electroplated 3/8-inch G70 hammerlock (see PS Advisor, this issue).
A double-jaw midlink can also serve as a temporary connector, as can a chain shackle. Chain shackles are U-shaped, as opposed to anchor “bow” shackles, which are bow-shaped to provide greater freedom of movement. Whatever you choose, you’ll want to source from a quality supplier and ensure and working load ratings meet or exceed that of your chain.
Chain rodes should be pulled and inspected at least annually (depending on use) but particularly after exposure to severe loading. Loading on a chain rode isn’t very high under normal conditions, however damage can occur when the chain is wrapped around an object (rock, wreck, etc) and placed under tension.
If you find your chain slipping or jumping out of the windlass wildcat (chain wheel) more than it typically has in the past, it could be a sign some of the links have been damaged and the chain may need replacing.
Ground Tackle Rogues’ Gallery
A marine surveyor’s life would be a barrel of fun if the outrageous stuff they uncovered wasn’t so dangerous:
1. This drop-forged anchor bent under extreme side loading. The best option is replacement (PS May 2013 online).
2. Practical Sailor discourages the use of swivels, even more so when used incorrectly. The jaws should be attached to the chain, not the anchor. As attached, an off-center load can result in point loads that lead to failure at the shackle-pin or clevis pin (PS September 2015 online).
3. Poor cleat and fairlead designs create an even greater liability when they are broken and neglected. (see Practical Sailor, March 2010 online).
4. A hardware store variety C-link never belongs in the rode sequence. They are simply not designed for this task. (PS Advisor June 2018).
5. Thimbles are standard for anchors and moorings. Installed incorrectly or subjected to extreme loads, they can contribute to chafe. Form splices under load and seize all thimbles in place with ample whipping twine. (PS December 2014 online)
6. This shackle is the wrong material for the job, not moused, and oriented incorrectly. The shank should bear upon the “bow” of the shackle, not the pin. Acceptable shackles meet or exceed Grade B standard (U.S. code RR-C-271 G; PS January 2017 online).
7. A cross-section of the bearing surface on a stainless-steel swivel like the one in photo 7 reveals threads that reduce tensile strength and invite corrosion.
8. A cross-section of the bearing surface on a swivel (photo 7) reveals threads that reduce tensile strength.
Capt. Frank Lanier is an accredited marine surveyor with over 30 years of experience in the marine industry. His website is www.captfklanier.com.