开云体育

ksmith4312,
I am not an engineer and barely a mathematician with only a BA in the subject but I know a little about physics and construction. I would prefer to put chain plates outside on the hull than move the chain plates to the doghouse roof for a couple of reasons. 1) the angle created by the new position and the spreaders would not give the designed 'proper' support to the mast in any respectable kind of wind, 2) the doghouse roof is not as structurally sound (thick) as the hull (@1/2" on my #328 T27) and would be prone to flexing and stressing due to it's shape, whereas the hull is thick and solid, although it flexes a little bit, 3) the jib and sheets would still have to get around them and might make going forward more 'interesting', 4) refer to suggestion 5, 5) don't do it, it is not safe, practical or reasonable.
It turns out that the stainless steel bolts that go through the chain plates need air to remain healthy and that in the original Tartan design, these bolts were entirely glassed in, depriving them of air and when water intruded they decayed, leaving many of our sailboats vulnerable to chain plate failure. I replaced the aft chain plate after it pulled up for this (these) reasons on my T27. I used Ipe (a wood from South America) as the stock, the original chain plate (chromed perhaps?), and new stainless steel bolts and re-glassed the entire thing (behind the rudder). The 'best' way to fix this problem, IMHO, is to keep the SS bolts outside of the epoxy so they get air. Rebuild the old knee walls with a solid piece of wood (or other material; starboard comes to mind) and put the bolts in last OR move the whole thing outside, to the freeboard. You will still want some kind of backing plates if you mount the shrouds outboard.
Glad to know that I am not the only one contemplating this chore.
CalebD
T27 #328, Odalisque, 1967