bobthebrat

Expanding foam will help it float.
With expanding foam, if you do get water in your boat, it wont make you sink, cause.... Expanding foam helps you float.
If your getting that much water in it when you leave it, it's probably best to put your boat on land if your afraid of it sinking with foam in it, let alone without.
It will get rid of most, if not all the vibrations.
It doesnt weigh much. Which means, easier to load, and the engine doesnt have to work as hard.

zzzzzzz

iTrader: (5)

1/2" foam sheets glue to the boat then get a sheet of 1 1/2 foam rap it then glass it to fit as a floor that you can remove

Expanding foam would be more work

look into glue that will not eat foam (most will )

all foam will help boats float

bobthebrat

non-toxic silicone will work best. I've used that lots on foam sheets.

deepblackwater

Jettalemon, wonder if rhino liner might work? You know the stuff that's sprayed onto the bed of pickup trucks for protection. The stuff is durable and it'd probably help keep your rivets from popping out as well making your boat more water tight. I've seen some people use the stuff on the decks of their boats so I'm assuming it should be fine for the interior of your hull. Other than that go fiberglass, I did and it was like night and day. Stealth is key!