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Wooden Boat Building and Restoration

Decks

With hull painting completed, the next step was the deck. Rebuilding the deck was what I was most looking forward to for this project and it took up quite a bit of time.

The original deck on the old Dunphy was made of ½” plywood, covered in vinyl, and trimmed in aluminum. For the restoration project the owner wanted a planked mahogany deck. The decking method I chose to do was a veneer laminated deck. This would provide a beautiful deck, that would be strong, and resilient to leaking. It consists of a ½” thick plywood base layer, covers with ½” mahogany planking with filled seams.

The boat’s transom was made of ribbon cut Sapele Mahogany plywood, while the original windshield appeared to me to be of African Mahogany. So I choose a combination of both of the wood species for the deck. The deck’s covering boards would be of Sapele Mahogany, and the deck’s planking would be of African Mahogany.


Work was begun on the new deck starting with the covering boards. The first challenge was the double curve by the windshield.  This section of the covering boards will be laminated. First, a template was drawn of the curve. Then the template was cut to shape.  Next the template's shape was traced onto a mold. Then clamping blocks were screwed down to the mold’s base along the traced curve. Next some Sapele Mahogany was milled to size and then resawn into ⅛” think pieces on the band saw.

             


Next the thin pieces were laminated together in the mold with epoxy and clamped tight to cure overnight.

             


Last excess epoxy was cleaned up and the laminated piece was sanded to its final form.

             


With the port and starboard laminated sections completed, the remaining sections covering boards, and king plank could be laid out and secured in place. Each section was butt jointed together using loose tenon joinery. I use Rockler's Beadlock Jig the loose tenon joinery. Some guys like the Festool Domino Joiner, its too expensive for my purposes. For the small twin rear decks, biscuit joinery was used. Last, the holes were bored and countersunk and silicon/bronze wood screws were used to fasten the covering boards to the sheer clamps, deck beams, and gunwales. 

             

             


With the covering boards completed, next was the veneered decks for the bow, and twin sterns. First a layer of ½” marine plywood was cut to shape and fastened into place as a base for the deck planking. The width of the deck was carefully measured so that an even amount of equal width planks could be established across the deck. Then the African Mahogany planks were milled to size, then carefully resawn and planned into ½” bookmatched planks. These planks were laid out on the deck, bookmatched on each side of the king plank, and trimmed to length.

             

             


Then ⅛”x⅛”  evenly spaced grooves were cut into the planks to create the appearance of narrow planking. Next the planks were cut to fit cleanly against the covering boards and screwed down. ⅛”x ⅛" rabbits were routed out on each end of the planks. Holes were carefully laid-out, bored, and countersunk in preparation for being fastened down with silicon bronze screws. Finally they were mounted onto the plywood substrate by adhering it to plywood with epoxy and then screwed down into the deck beams. 

             

             


Last, the screw holes were filled with mahogany bungs, then cut flush, and the entire deck sanded.

             


After the deck was sanded, the entire deck was coated with Total Boat Pentrating Epoxy followed by 5 coats of varnish.  These initial coats were the "build-up" coats and were sanded between coats with red 3M Very Fine Scotch Brite pads. There was one last thing to do before applying the final 3 coats of varnish... filling the deck seams. I used white Sikaflex 295-UV for the seam filler. Before filling the seams I think its best to mask off deck planks leaving only the seams visible. Also I very carefully used the hooked handle of a old file to scrape clean the ⅛” grooves of varnish so the Sikaflex would stick well into the seams. The Sikaflex can quickly get very messy, so its best to just mask everything off. I used an air powered caulking gun to apply the Sikaflex, followed by a convex shaped putty knife to create a nice smooth conceived shaped texture to the seams. This process can test your patience.

             

             


To complete the decks, three final coats of varnish were brushed on with a badger hair brush. Sanding between coats was done with gray 3M Ultrafine Scotch Brite pads. I waited two full weeks for the Sikaflex to thoroughly cure before applying the final 3 coats of varnish.