Thats a nice looking party boat. Plenty of walk around room on that thing. ON the 23's there is space (couple inches) between the liner and hull. That is why it sounds hollow. The cap, hull, and liner are screwed together on the top from the outside. Rub rail goes over the screws. On the Potter built boats the liner is bonded to the tops of the stringers (very wide stringers) with cabosil. That is were you will have problems breaking it free. Not that is undo able but it will be difficult. I was able to break my liner free but I had to do some cutting. On the 20 sf the liner is part of the transom and is bonded wiht cabosil so it would have been in possible to break that apart. So I cut the liner in front of the transom. We then used a come along and lifted the liner out. We actually lifted the boat off the trailer trying to break it free.
To answer your question yes I would try to get to the bottom of what the sound is that you hear but I would try first without removing the liner. I dug out an old thread were a guy called "Salvagefirst" actually did what you are talking about (removing the cap and liner) The pic's are gone now. Finster posted the pics for him so maybe you could pm Finster and see if he still has the pics. Salvagefirsts boat was a tracker boat and his liner was not bonded to the transom and he said it came apart without too much difficulty. Sorry to ramble. Hope I helped some.
http://www.classicseacraft.com/forum...3&Number=25965
strick