Looking at this photo of the bulkhead on one of the 500 series boats ... can't be 3/4. Actually I'm thinking we had covered this 4 years ago.

The 200 series Boats have a 3/4" core in the bulkhead

Rhapsody has 3/4" core in the bulkhead. I plugged the old instrument holes when I mounted the TackTick dovetail holders.

Wow, the earlier boats must have a much thicker aft cabin bulkhead. Natural High's is at least 3/4" of balsa core.

On Conundrum, #484,my bulkhead is 3/8 plywood, glassed over. I plugged all my instrument holes when I recored the deck and hull.
Also interesting after seeing #477, I have the old 6 berth interior and the new Cockpit. Wonder what Blue Meanie #485 has.

Are there any class restrictions on replacing the balsa core? For example can a composite core be used instead of the original balsa core? I am specifically thinking under the winches both on the deck and on the cabin top? As always any and all advise is welcome?

Thanks,

John

Presto # 436

currently there have been no objections to selection of core. when we rebuilt transom on 526 we used G10 scrap squares to completely eliminate water penetration.

as of today were plenty of options on Ebay under G10 sheet. I would check specs on the brand name.

I used a biaxial cloth from U.S. composites I think the part number was 1708

Yes, U.S. composites. I ended up with 3 layers of 1808 biaxial ( 0-90 deg. thread orientation) and a layer of 3/4 oz. mat for the outside layer. Being my first fiberglass project, I relied on the advice of a fiberglass guy and everything looks good so far. I am going down today to grind and fair it....

Interesting to read earlier posts and the varying differences between boats over the years. Our cockpit bulkhead core is 3/8" on Kinesis. Very surprising to see they went back to the double quarterberths at one point. Maybe that was a custom order?