i have seen no core in my hull... i am putting my shoot thru under the galley sink...i havea copy of the c26 manual and it mentions no coring material in the hull lay-up schedule..there is some in the deck and around the keel boats for reinforcemnt but that seems to be all

there are several through hulls on mine transducer included i dont think the hull is cored Its straight glass lay up, I know if your remove the paint of the none of the hull you can see through it.