Saturday morning I continued looking with a couple of new ideas and a steely calmness. I had decided if didn’t find it within an hour, it would make more sense to fabricate a new one, and at worst I would have a cleaned up shop. Even with a cleaned shop and an extended search, I didn’t find it. I found several other long-lost odds and ends, but no bracket. For the first time, the wisdom of Sherlock Holmes had failed me. (When you have eliminated the impossible, what remains, no matter how unlikely, must be so.)
I spent the rest of the day chiseling out old caulking, cleaning out the skylight framework with a wire brush, buying replacement plexiglass, and scouring hardware stores for a suitable piece of aluminum stock to fabricate the new bracket.
I wanted to leave the protective film on the new plex until the skylight installation was complete, so I trimmed off about a half an inch of the protective film around the perimeter to allow it to be inserted and sealed in the frame.
That night I fabricated the new bracket and reassembled the skylight with new plexiglass (smoked instead of clear) bedded in marine silicone sealant. The plexiglass is not fastened to the frame, but rather ‘floats’ within the assembled frame in a bed of sealant. The aluminum framework, in turn, is screwed onto a fiberglass flange on the doghouse roof. Below the frame on the underside of the doghouse roof is a teak trim surround.
Because the plexiglass panel floated in the frame, and the frame pieces could not be precisely and perfectly connected, I expected adjustments would be necessary to fit the assembled window back in place in the doghouse roof even though the replacement plexiglass panel was exactly the same size as the original and the frame was assembled in the same order as it was originally. 
Trial fits on the boat on Sunday confirmed my suspicions. It took quite a bit of grinding away of old sealant and some fiberglass to get the assembly to fit in place.
Even then, it was obvious some of the bolt holes did not line up any longer and will need to be redrilled. I was out of sanding disks to finish the trimming, and there wasn’t time left to start on the big task of rebedding and re-bolting the skylight in place. Instead, I sanded the teak trim around the opening and put a coat of epoxy on it.
Because Carol will be visiting next weekend, I had to allow some time to clean up the mess on deck and in the cabin. Being a pretty hot and humid day, I thought it was a good time to try out the funky airconditioning unit on board. After I got a few wires and switches sorted out, it came to life and actually worked. It was great standing right in front of it, but it clearly didn’t have the capacity to cool the entire cabin. With everything reasonably sorted out, it was time to head for home.
I have to say I am a bit skeptical about the way that the plexiglass is just "floating" inside a frame with some silicon sealant - given enough force - perhaps a wave, a knockdown, a cobination or 180 - the plexiglass may flex enough to cave inward. Given the huge size of this window, I would rather thru bolt the plex for some good measure, or fit a storm shutter assembly. This is not to say that the plex would not shatter given the thickness either - bolts or not. I would sleep better if it was 1/2-3/8 thick, thru bolted, and/or backed up with a shutter. Don't like large windows.
ReplyDeleteReminds me of why structurally manhole covers are engineered to be round instead of square.
But more importantly. where the hell did the old bracket go?
The plex is 3/8 inch thick, so is strong enough to stand on. You have to be careful through-bolting plex. The holes need to be oversize to allow for expansion and contraction and washers (no countersinking!) used. Otherwise the plex can crack at the fastener. I recently learned that the crazing of plex that always develops with age is structural and not just aesthetic. Once the plex develops it, it can shatter into hundreds of sharp shards with an impact. As for Circadian's doghouse, think of it as a hard dodger and you'll sleep easier. It could be completely removed and would not harm the structural integrity of the boat. The campanionway doors and hatch under it are another matter...that's why I glad to have the sturdy doghouse!
ReplyDeleteStill haven't found that damn bracket! Even Murphy failed this time! (According to the fifth corallary of Murphy's law, you will find the missing part immediately after buying or making a replacement.) A black hole in the shop?
Well, if you aren't too worried about it, and given its a hood instead of the cabin...I'll regress back to the cave.
ReplyDeleteI see a lot of debate out there about whether lexan/polycarbonate or cast acrylic is best for hatches and windows. I'm leaning toward trying acrylic if I ever get to that point again.
The damn bracket - maybe it bounced up somewhere and isn't where you think it would normally be - say the floor? Also, maybe you are too close to the problem and have a case of the ol' brain lock. Having someone who normally isn't in the environment come in and help you look - bet they would find it right away. Maybe Carol or someone nearby can give a quick peek. Not sure why that works but seems to be related to quantum theory.
fun stuff...