Yeah, You won't really hear thumping in a bigger, or, Heavy boat. Simply because the ballast is keeping you in the water, so you sit on the waves, rather than go up, then SLAP back down onto the next.
Also, How much a boat draws (Depth) can also be a factor, a boat that draws more water is generally heavier, and so, more boat is in the water. That way you have no slapping at all (Like Mary Elizabeth).
Whereas, take a boat like say, that's around a ton, maybe less, with not much depth, and a lot of speed - That's a boat that will slap around a bit. I can tell you that from a bit of experience between Forty Winks (The boat we have now) Compared to Mary. There's a big difference in a ton and 4.1 Tons.
Jack