J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Deck core

I'm going to replace the soft core in the dock of Sleighride, hull #55. What is the thickness of the balsa core on the cabin top? Is it the same on all of the deck? is there balsa or a different material under the winches, clutches, cleats etc on the cabin top? Has anyone used foam instead of balsa when replacing the core? Thanks!

Greetings Phil,

3/4". This is the same for the main deck including under the winches, cockpit deck, transom, hull and on at least some boats, the bulkhead to the left and right of the companionway. The 45 degree section connecting the cabin top to the main deck is 1/2", at least on my boat. Under the primary winches, expect to find a 12"x24" section of balsa cored deck that is doubled with extra layers of glass between the main deck core and a lower 12"x24" 3/4" marine fir plywood doubler.

Numerous people have used foam core instead of end grain balsa and there is no short supply of people touting the virtues of each with arguments ranging from never wanting to smell decomposing balsa again to wanting to keep the flexural modulus the same across to sections that did not get re-cored. While I chose balsa, my opinion is that either is just fine as long as the common workmanship topics are addressed such as grinding out 12-to-1 scarf joints to the adjacent FRP, never using polyester or vinylester on top of epoxy, fully scrubbing the blush off of cured epoxy and properly epoxy isolating the new holes you drill to remount the deck hardware.

-Chris

Thanks Chris,

It's exactly as you said except there is just core under the winches, etc. I'll use Corecell foam and have most of the cabin top rotten balsa removed and am starting to install the foam with proper bevels on the edges structural epoxy in bolt/screw holes. Predictably some areas were better than expected and others worse. The deck is next, followed by the cockpit. It should make the boat stiffer and lighter.