Oak to oak

Greetings,
What are your opinions about ways to attach 2" thick oak boards to oak ribs on an old fishing vessel? The boards are about 8 to 12" wide. Are there any modern fasteners which would do it better than the old galvanized square nails? What about a 'huge rivet' approach, with one end peaned?

 

Trunnels

Steve

 

Cut nails hold pretty well, but not as well as screws of bolts. I wouldn't rivet, just finding rivets big enough may prove troublesome, not to mention preening over the ends. 2" oak is substantial planking, even for an old working vessel. Under the waterline I can understand thick carvel planking (on a working craft), but above I would skip the bother and double plank with 1" stock.

My main concerns are; difficulty in getting particularly rift grained 2" stock for the planking. Planking this size will need to be especially straight grained and quite vetical or you'll get a lot of movement and leaks. Double planking the topsides solves this issue, where the planking will not be completely soaked most of the time. A second concern is the size and spacing of fasteners necessary to secure 2" planking. 3 1/2" (minium) number 16 flathead screws would be my suggestion or as close of centers as you dare in the tight bend areas of the hull and along the garboard seam.

If this is now a pleasure craft and not carrying a hefty load for a living, then I'd strongly consider double planking the whole hull. You can use a lesser grade of lumber on the inside layer and you will eliminate the need for caulk seams, though you'll still have one at the garboard and along the rabbit. Tunnels are an option, which don't rust or cost a small fortune or cause a dissimilar metals situation (electrolyses) with your boat.

 

Have seen bolts used for this thickness (when refastening), though the vessel's framing was 5inches thick at the thinest, bolt dia approx 12-14mm, very heavy but then she was built as a cargo ship in the late 40's. Oak as well.