Tiny boat, probably got considerable water onboard.

With admittedly close to zero sailing experience, I would think that if your boat (no matter how big or "tiny") is getting "considerable" water onboard, you have bigger problems than your canned food.

It doesn't make sense to me either that the size of the vessel has much to do with how watertight it is.

But like I said, I don't have much experience in this!