We have recently undertaken a refit on our vessel Whanake. This included replacing all of the original 42 year old 316 stainless steel chainplates. From inside the vessel they looked sound but we were suspicious as we had experienced years of deck leaks at the chainplates (despite several times re-bedding the chainplate covers on the deck). These leaks only occurred when under sail to windward. We decided to remove all the chainplates to inspect and replace as necessary. On removing the chainplates up through the deck several broke with serious internal corrosion – and these were substantial plates of 12mm thick, 70mm wide and more than 600mm of length bolted to hull beams. This clearly explains the deck leaks – with the rigging under strain to windward there was enough movement in the weakened corroded plates to open up the sealant between the plates and deck structure to let in water. So all the old chainplates were condemned and we got new chainplates made up with much stronger 2205 stainless. The first test of these new chainplates was on a recent crossing of the Tasman Sea where we had beam seas for the first couple of days with the decks awash - not only does Whanake now feel stiffer under sail and sails better to windward, she is bone dry below. We see at least 40+ years life in these new plates so unless we are octogenarians and still sailing Whanake it will not be our job to replace them. Other Cruisers have commented about annoying deck leaks but again only when under sail – so after our experience, removing and inspecting chainplates would be on the top of the list. Not only could it fix an annoying problem, it could also avoid a potential catastrophe at sea.

Excellent post. Many thanks. I wonder why stainless 2205 is not routinely used?

Hi Shills,
Good post and probably an excellent reminder to many an offshore sailor. I am in the process of swapping chainplates on an almost 20 yo offshore vessel, a Valiant 42. I believe that CP 's should be swapped out for new (or removed and inspected) on a regular basis as regular maintenance item, like the standing rigging.
I am also very impressed that any 42 yo offshore boat would be bone dry on an offshore passage.
Thanks for the field report.
My best, Dick Stevenson, s/v Alchemy