P39-2 has balsa cored bottom below waterline
As a happy owner of P39-2 hull#12 manufactured in 1987 I can confirm that my boat has balsa cored bottom below the waterline. I can also confirm that it has NO problems with any blistering but have to admit that the previous owner that bought this boat new had put antiprotect 2000 early in her life and just 2 years ago I redid my bottom applying more interprotect 2000 before anitifouling paint.
I also have to say that last year I survived substantial grounding with bashing against rocky bottom for approx 6 hours in 2 ft wave heeled about 45deg. I thought that after that my boat will be a writeoff but after carefully checking the floor-boards and tabbing on them I have to say that amazingly there was NO damage except to the tip of the lead keel and tip of the rudder. This boat is like a rock and sails like a charm. I am convinced that the cored bottom allowed such grounding to cause no damage. I also know that few other boats that grounded at the same place had never sailed again.
If anybody is interested in more info on P39-2 please give me a holler.