The Anchor Chain That Had Two Links Left
By Gus Marchetti, Salvage master. Reviewed by Dana Whitcombe, technical reviewer.
Underwater Inspection | Cathodic Protection & Anodes The chain lay across the pier like a black iron python, and I counted the links as a reflex. One hundred and seven. The owner of the F/V Karen Marie was standing beside me, arms crossed, and he didn't look happy. He said, 'I just had it fixed last year.' I didn't answer. I was looking at two links that had about five minutes of use left. It was a Tuesday in May, the harbor at New Bedford, Massachusetts. The air smelled like diesel and bait. A salvage job had just finished early, so I'd agreed to look at the anchor chain of a local dragger. The boat had been dragging for scallops on Georges Bank and the anchor came up with mud. The crew did what they always do: they hosed it off and dropped it. But the deckhand saw something when the chain came through the hawsehole, and he called the owner. The owner called me. The chain was stored in five-meter shot lengths, laid out on the deck. Two links caught my eye immediately. They were the last two links before the anchor shackle. Not the flashiest place, but the most important. I walked over, knelt down, and pulled a wire brush from my jacket pocket. I gave each link a couple of strokes. The rust flakes didn't just fall—they rang on the concrete. That's the sound of steel that has been eaten from the inside out.
The First Link: Corrosion That Started Under the Galvanizing
The first link looked solid enough from the outside. The tell was a faint discoloration on the underside, a patch of dark red against the gray of the galvanizing. I flipped the link and ran my thumbnail over it. A flake came away, and underneath was a pit the size of a pea. It was a classic case of under-film oxidation: the galvanizing had been worn off by sand and shell, and the seawater had gone to work on the bare steel. Over years, the pit had grown inward until the link had lost nearly a third of its cross-section. A link like that can go in a calm harbor with no strain at all. The anchor wasn't holding anything that day, but if it had been set, that link would have opened like a fish hook. There was no tool on the dock that could show that pit without pulling the chain apart. That's why you need to measure link diameter, not just look. A set of calipers is the cheapest insurance you can buy. When the link diameter is 10-12% below the original, the chain is finished. That first link was almost 15% under. It had no business being anywhere near an anchor.
The Second Link: A Welded Repair That Was Too Quick
The second link was worse because it looked brand new. It had been welded into the chain a year ago, and the top of the crossbar showed a smooth, shiny bead. That should have been the giveaway. A proper weld on a high-test chain doesn't look pretty; it looks like it was done in a controlled shop, with a preheat ring and a post-weld wrap. This one was a yard repair, done on a lunch break, with an oxyacetylene torch and whatever rod was in the drawer. The weld metal was fine on the surface, but the heat-affected zone—the area just next to the weld—had cooled too fast. That made the steel brittle. I didn't need to cut the link to find the crack. I wiped the joint with a rag, waited for the angle of light, and saw a hairline line running from the weld toe toward the shoulder. It was precisely the kind of crack that starts at the point of highest stress and grows until the link parts. I've seen that crack on tow wires and lifting pins. It never ends well. The lesson is simple: if you don't know the repair procedure and the heat treatment, you don't know the chain. The owner told me he had paid 'a guy at the boatyard' to fix it. A few bucks saved bought him a potential catastrophe.
What the Chain Was Telling Us
Those two links were not random failures. They represented two different ways you can lose an anchor: neglect and bad repair. The first link had been abused by the environment, the second by a human being. Neither showed up in a quick walk-around. The owner then admitted that this chain was not original to the boat. He had bought it second-hand from a local supplier. There was no documentation on its history, no proof-load certificate, no record of how long it had been used on the bottom. A chain like that is an unknown. And an unknown chain is just a shaped piece of scrap. We took the last five meters off the chain and sent it to a test house. They ultrasonic-tested every link. The report showed that the two links I had flagged were indeed below the breaking threshold. They also found three more links that were close, but the two were the ones that would have gone first. The owner was lucky. He hadn't anchored in a storm with a day's catch on board. He hadn't lost the anchor inside the mouth of the harbor. He had a chain that was about to part while it was lying on a wooden deck.
The Fix: Not Quick, Not Cheap, But Cheaper Than Losing the Anchor
We removed the last fifteen meters of chain without argument. Actually, we removed the last shot, measured it, and ordered a new one to the exact spec. The new chain came with a mill certificate and a proof-load test. We fitted a new anchor shackle and pinned it properly. The owner grumbled about the cost, but he paid it, because the alternative was a lost anchor and four hundred dollars of ground tackle at the bottom of the Atlantic. The work took a day. The hardest part was convincing the owner that a visual look by his deckhand wasn't enough. Nobody likes to spend money on something that goes unseen all season. But an anchor chain is exactly the thing you want to be boring and unremarkable. I kept the two original links after they were cut out. I wire-brushed them, placed them on a shelf in my office, and watched them rust slowly side by side. They remind me that every failure has a story. The anchor chain that had two links left was a local story. It could have ended with a quiet accident and no one to blame. Instead, it ended with a hard lesson, a new chain, and a fisherman who now asks questions before he buys used gear.
Frequently Asked Questions
How can I tell if my anchor chain is about to fail? Look for pits, cracks, and loose scale. Measure the link diameter with calipers at the top of a link, the bottom, and the bend. If it's more than 10 percent under the original size in any spot, it's nearing the end of its life. For a real answer, have it proof-loaded or ultrasonic-tested. That's how you find defects that don't show on the surface. Can I just cut out the bad link and weld in a new one? Yes, but it must be done right. The new link has to be the same grade and diameter. The weld has to be the right alloy, with proper preheat and controlled cooling. After that, the chain has to be proof-loaded to its working load. A local welder who hasn't done it before is not the one to trust. A certified test house is the only place a chain gets that kind of care. How often should I inspect my anchor chain? At least once a year, and absolutely after any rough service like dragging in a storm or a grounding. A quick washdown and a look at the links that go through the windlass is a start. A full survey with calipers and a written record should be part of your winter layup. Chains don't wear out equally—they wear at the points that touch the windlass, the bowsprit, and the bottom.