In regards to building with Divinicell core within a female frame jig (rounded chinned hull designs), would it not be possible to score through up to 70% of the thickness longitudinally … Instead of cutting the foam in narrow strips and routing all the edges with the subsequent loss of material.
Similar to what was done on some of the panels of the hard chine F12 Kiwi design, but with much more precision… (in the raw foam, not foam that has already has been glassed) using a fence and narrow blade in a circular saw where you can regulate the exact depth and width of the cut rather than just free handing it with a 4" grinder. One could also make similar cuts on the horizontal plane at the bow (although the cuts might not need to be as deep)where a compound curve is encountered. The spacing of the cuts could be tailored to the particular hull shape, instead of either going with the strip/rout method or to the factory cut contour panels with the scrim backing, which would be too flexible when used within a female jig frame.
Would it not offer a savings of both time and material?…H 80 Divinicell isn’t cheap @ $100.00 US a sheet, and over the course of 14’+ cat you could end up with 2/3 rds-to a full 4’X 8’ sheet of foam on the floor in the form of dust. Depending of course on the width of the strips cut, the width of the saw cut, and the amount of loss when you rout the male and female radius on the edges. My 12” table saw takes 3/16” of material per pass, loose another 3/16” from the routing process on the concave side (1/2 the 3/8” radius) I would loose 3/8” of material for each cut. For sake of argument say the strips are 2" in width...you would lose about 8" of width out of a 48" out of every sheet...or get 20 strips instead of 24 strips per sheet. In the course of 6 sheets you would lose a complete sheet to just cuts and routing.
Based on using 3/8”X 4' X 8' plain Divinicell sheets and ripping it into strips and doing the cove routing method. H-80 Divinicell 3/8" thick, each sheet is $100 US at this point in time...and that is 1/2 of the list retail price.
I am referring to the build method they used for the LR2/LR3 which is quite ingenious, but can’t resist the possibility of tweaking it to make a more efficient use of materials
Has this been tried with cat hulls in a female frame jig? I have used this technique before when vacuum bagging a 6mm Divinicell deck over EPS core on sailboards. I put relief cuts parallel to the rail where the core was too stiff to follow the rail curve. The vacuum could not exert enough pressure to pull down the Divinicell tight to the EPS core (due to the small radius on boxy rails) without the relief cuts.
