Bridgedeck

Pure Seal update?

Posted by Paul

As has become customary for the start of each season, the PureSeal plate gets an inspection and a report. This morning I forgot to go and check them so I will report on them tomorrow.

Back on the boat build, I have decided on 4 bridgedeck stiffening pipes and decided that pvc rectangle down pipe is perfect for the job. The problem with the current method is that the plans call for gluing full round 60mm OD (Outside Dimension) pipes to be glued to the bridgedeck along its length (so about 7.5 meters) then have the space on each side of the curve of the pipes filled so that they are coved out to take the glass over them. This is a lot of coving. You have to fill a space that does not need to be there.

My initial thought was to buy 120mm OD round pipe and cut it in half to retain the 60mm height from the bridgedeck but only have close to a right angle to cove but then I realised it is going to be difficult to cut a pipe 6 meters long exactly in half even with a table saw and fence because whilst you may be able to ensure the distance of the cut from the edge of the pipe, the round pipe can rotate and you can end up with a twist in the cut.

So my solution is pvc rectangle down pipe. I have found 110mm x 55mm which if cut in half will result in almost the size I need. I think the reason the round pipe specified is 60mm OD is because the strength comes from the layers of uni that run parallel to the hull 60mm away from the bridgedeck and held in place with another layer of glass overlapping to the bridgedeck, otherwise if it wasn’t the distance from the bridgedeck you could just run uni down the bridgedeck itself without the pipe. The rectangle pipe will cut down the middle to make 54mm x 55mm (you lose 2mm in the saw cut) which I think is close enough. I was originally thinking of having 3 stiffeners but have seen Schionning cats with 5 (and Bruce Hodgens in his CD suggests that while he used 3 stiffeners he would use 5 on another build) so I have settled on 4. The flat surfaces of the rectangle (or half of the rectangle so now square) pvc pipe will make sanding it to key it so the glass sticks to it easy, a flat surface to glue the 2 layers of 40mm wide uni to and nice curves on the edges to glass to, and of course a lot less coving material needed. And finally being rectangle it will be much easier to cut on a table saw and fence.

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Paul