Re: "The chainplate will buff out and probably be okay"
The chainplate knees on Tayana 37s are notorious 'mushroom farms' that hold but never release the moisture ... the constant moisture is what has caused the crevice corrosion on the (probable) 302 Stainless OEM chainplates. There's wood behind all those fiberglass knees, and was used to affect a 'form' over which the knee's fiberglass was layed.
On a Ty37 when you remove the plates if you see 'any' rust blooms emanating from the studs .... and/or seeing such 'rust blooms' on the chainplates themselves - the only remedy is complete and total rebuild of the knees, and serious consideration of new plates. This high suspicion of internal rot should also be held if there are any chainplate studs that have 'rusted off' at the outer surface of the fiberglass knee.
BTW such rotted knees on a Ty37 is not just a 'lack of maintenance' item of routine recaulking the plates' thoughdeck; but, is pretty indicative or high suspicion of a Ty37s teak deck needing removal and the under-deck needing a total re-core -- a backbreaking or 'very costly' job, your choice.
Last edited by RichH; 11-24-2012 at 07:21 PM.