Re: Centerboard problems
Posted: Wed Sep 06, 2017 7:56 pm
This isn't a problem yet, but I'm posting to ask advice about the centerboard pivot installation to prevent one:
Page 26 of the PS manual advises leaving the "epoxy-filled" (pivot) holes in the forward end of the developing centerboard trunk "until much later." Page 223 notes that we've "located and drilled out the pivot hole" for impending installation of the centerboard. At this point of course, the centerboard trunk is a completed, integral part of the hull - and it seems that the "port" and "starboard" pivot holes must be at right angles to the keel and perfectly lined up with each other to allow installation of the pivot rod and appropriate CB pivoting. Also, as we drill the pivot holes on each side of the trunk, we must avoid penetrating the thickened epoxy in the holes which would defeat the protection of the trunk from future water damage.
#1 - I'm wishing I'd drilled those holes before I'd built the trunk when I could position the two trunk sides exactly together, one over the other. (See #2 below for why.) I also wish I'd drilled the holes a bit oversized so I'd have more diameter through which to now drill the two holes for the pivot rod. (And in fact, were I to build another PS, I'd make a number of the "drill-fill-drill" holes a bit bigger. John Harris has endorsed that with respect to the companionway hood drain holes and the holes draining the footwell through the transom.) But penetrating the hardened epoxy and inadvertently touching centerboard trunk wood is a disaster to be avoided; if it were to happen, it's critical to recognize it at the time and re-seal the spot with epoxy, even if it means re-filling the hole with thickened epoxy, without leaving slag on the inner trunk surfaces.
But #2 - How are builders ensuring the pivot, when installed, is indeed at right angles to the keel (so the CB is free to drop)? It seems that some filing of one or the other hole will be required to get the pin to fit through the CB trunk opening.
And #3 - Don't I want the 3/8" stainless steel pivot rod itself to be motionless once it's sealed into the trunk with thickened epoxy, while the pivot hole in the CB is just slightly over 3/8" in diameter to allow the CB to swing freely on the pivot? It seems I wouldn't want the rod to "work" at all as the CB was lowered and raised over time. Maybe I'm worrying too much, but other PS Forum posts about water damage in the CB trunk have made me properly scared.
Thanks for any advice,
Mark
ps - Maybe "Were I to build another Pocketship..." deserves its own subject line in the PS Forum.
Page 26 of the PS manual advises leaving the "epoxy-filled" (pivot) holes in the forward end of the developing centerboard trunk "until much later." Page 223 notes that we've "located and drilled out the pivot hole" for impending installation of the centerboard. At this point of course, the centerboard trunk is a completed, integral part of the hull - and it seems that the "port" and "starboard" pivot holes must be at right angles to the keel and perfectly lined up with each other to allow installation of the pivot rod and appropriate CB pivoting. Also, as we drill the pivot holes on each side of the trunk, we must avoid penetrating the thickened epoxy in the holes which would defeat the protection of the trunk from future water damage.
#1 - I'm wishing I'd drilled those holes before I'd built the trunk when I could position the two trunk sides exactly together, one over the other. (See #2 below for why.) I also wish I'd drilled the holes a bit oversized so I'd have more diameter through which to now drill the two holes for the pivot rod. (And in fact, were I to build another PS, I'd make a number of the "drill-fill-drill" holes a bit bigger. John Harris has endorsed that with respect to the companionway hood drain holes and the holes draining the footwell through the transom.) But penetrating the hardened epoxy and inadvertently touching centerboard trunk wood is a disaster to be avoided; if it were to happen, it's critical to recognize it at the time and re-seal the spot with epoxy, even if it means re-filling the hole with thickened epoxy, without leaving slag on the inner trunk surfaces.
But #2 - How are builders ensuring the pivot, when installed, is indeed at right angles to the keel (so the CB is free to drop)? It seems that some filing of one or the other hole will be required to get the pin to fit through the CB trunk opening.
And #3 - Don't I want the 3/8" stainless steel pivot rod itself to be motionless once it's sealed into the trunk with thickened epoxy, while the pivot hole in the CB is just slightly over 3/8" in diameter to allow the CB to swing freely on the pivot? It seems I wouldn't want the rod to "work" at all as the CB was lowered and raised over time. Maybe I'm worrying too much, but other PS Forum posts about water damage in the CB trunk have made me properly scared.
Thanks for any advice,
Mark
ps - Maybe "Were I to build another Pocketship..." deserves its own subject line in the PS Forum.