Anchor Chain Inspection: Measuring Wear, Regalvanizing or Replacing, and Matching the Gypsy

Switch off the windlass power and secure the anchor. Pull the rode out by hand and lay it in long straight runs or big loops. Practical Sailor warns that dragging chain over a concrete dock scrapes off the galvanizing and starts rust, so lift and lay it, or put down old carpet first. See the chain locker guide for cleaning the locker while it's empty.

Hose and brush off mud and salt so you can see the metal. Walk the whole length slowly, turning sections over. Flag anything suspicious with tape or a zip tie and photograph it. You are looking for:

• rust, and how deep it goes (step 3)
• links that are worn thin where they rub on each other (step 4)
• bent, twisted, stretched or flattened links
• cracks, especially near the weld on each link
• lumps of zinc, weld spatter or rough spots that catch on the gypsy

Not all rust is equal:

• Light brown staining where the zinc is wearing thin, mostly on the end that goes out first: the coating is going, but the steel is still fine. Time to plan end-for-ending or regalvanizing.
• Rust that flakes off with a wire brush, leaving a rough, pitted surface: the steel itself is being eaten. Check the wear closely (step 4).
• Deep pits, scaly layers, or links that look smaller than their neighbors: real metal loss. That section, and often the whole chain, is due for replacement. Practical Sailor's rule of thumb: once rust starts to appear, the chain should be regalvanized or replaced.

Chain wears most where each link rubs the next one, inside the curved ends. With a caliper, measure the bar thickness of a link at that contact point, then measure an unworn part of a link from the bitter end, which rarely leaves the locker. Measure on the bar away from the weld, which can be slightly thicker. Do this at several places along the first stretch that goes out every time; that's where wear is worst.

The difference tells you how much steel is gone. There is no single wear limit for every recreational chain. Ask your chain maker or a rigger for the discard limit for your grade and size, and treat any clearly thinned, pitted or grooved link as a weak link. A chain is only as strong as its weakest link.

Jimmy Green Marine, a chain supplier, measures chain over 10 links, outside edge to outside edge, because one link is too small to measure accurately. Measure 10 links in a worn section and 10 links in an unworn section. If the worn section is noticeably longer, the links may have stretched or worn into each other. Any bent or opened link, a crack at a weld, or a link that won't sit flat means the chain has been overloaded; don't use it as your primary rode.

• Anchor end: the shackle or swivel between chain and anchor. Practical Sailor says shackle pins must be moused with stainless wire, not plastic ties. Replace a shackle with worn threads, a thinned bow or a bent pin.
• Joining links: Practical Sailor warns that hardware-store C-links (quick links) never belong in an anchor rode. Proper joining options are rated connecting links and shackles at least as strong as the chain, and some won't pass through the gypsy.
• Bitter end: the inboard end should be lashed to a strong point with rope you can cut from on deck, not shackled or wired. See the chain locker guide.

If the worn end is just losing its galvanizing and the rest is good, turn the chain end for end. Practical Sailor recommends doing this every year so the coating wears evenly. Move the anchor shackle and the bitter-end lashing to their new ends, and remember your depth marks now count from the other end (step 12).

Regalvanizing means the chain is cleaned and dipped in molten zinc again. It can make sense for a long all-chain rode that is rusty but still has its full strength. Things to weigh:

• Condition first. Regalvanizing restores the coating, not lost steel. Pitted, thinned or damaged chain should be replaced.
• How many times. Practical Sailor says chain should be regalvanized no more than twice before it's replaced.
• Grade. Boating New Zealand explains that the heat of hot-dip galvanizing can make heat-treated high-strength chain more brittle and weaker, possibly unevenly along its length; it reports a chain supplier saying lower-grade chain can be regalvanized once or twice, but higher grades probably shouldn't be if you need their full rated strength. Ask the galvanizer and the chain maker before regalvanizing any high-grade chain.
• The process. Chain has to be spun or shaken while it's dipped so the links don't fuse together. Ask the galvanizer whether they do anchor chain specifically, and expect lumps to need grinding off so it runs through the gypsy.
• Cost. Galvanizers usually charge by weight with a minimum charge, so for a short length of chain on a rope-and-chain rode, new chain is often about the same price or cheaper. Get a quote and compare it to new chain of the same grade.

Before buying new chain, find out exactly which chain your gypsy was made for. Look for markings cast or stamped on the gypsy itself, find the windlass model and serial number, and check the windlass manual or ask the windlass maker. Maxwell notes it offers chain wheels to fit almost every chain size on the market, so the same windlass can be fitted with different gypsies; don't assume yours is the original.

Buy chain that the windlass maker or the chain supplier confirms fits your gypsy: same size, same grade or calibration, and the same inch or metric standard. Inch and metric chains of "similar" size are different and won't run properly. Jimmy Green's method if your old chain fit well: measure 10 links of an unworn section, outside to outside, and give that number with the gypsy details to the supplier. Even better, take a short sample of old chain or the gypsy to the store and test the fit. Chain that doesn't match jumps off the gypsy, jams in the chain pipe and wears both. If you're also changing grade or size for more strength, plan on a new gypsy too.

Lay the new chain out, attach the anchor shackle (moused with stainless wire) and lash the bitter end. If you have a rope-and-chain rode, the rope-to-chain splice must be one your windlass can handle; follow the windlass maker's instructions (see the rope splicing guide). With the boat at the dock, feed the chain over the gypsy slowly, then run out and recover several yards under power. It should seat in every pocket without riding up, jumping or binding in the chain pipe.

Put depth markers on at your usual intervals (see the anchor rode and scope guide), checking they pass over the gypsy. Record in BoatMend the date, chain grade and size, length, supplier and whether it was new, regalvanized or turned end for end. Old chain is steel: a scrap metal recycler will usually take it.