slocum vs passport
Actually, all tankage on the Slocum 43 is readily removable without any deconstruction of the boat. The fuel tanks come out through the locker in the aft cabin. That locker as originally constructed was designed to be unscrewed and removed. The holding tank is also easily removed straight up into the cabin. This from experience as I have personally removed all the tanks on Sea Fever. From reading some other missives, such is not the case for the Passports.
The Passport 42 and the Formosa 42 version of the boat were solid layup below the waterline and I do not know the material used for coring the deck and hull above the waterline. The Slocum hulls were cored to the keel using Airex with all through-hull locations surrounded by solid lay-up. Watch out for POs and yard monkeys drilling through the cored areas without laying up a solid ring around the hole(s). I have never seen any problems with the Slocum hulls having water penetration.