Thanks for the tip, John!
Here's a bunch of follow-up questions to deter you from helping me in
the future.

Did you mean to say that you used the foam padding naked instead of
with the vinyl(?) cover? If so, is it the kind of stuff that might
cause rashes in contact with sensitive skin? Was if a matter of
breathability? Could the padding be covered with fabric? Did you affix
them to the floor? What kind of boat do you have?

What about making the padding removable for drying (Velcro, etc)?
Also, is it worthwhile to look at padding that's marine specific (i.e.
mold, mildew resistant?)

I'm sorry about pestering everyone here, but I assure you I am taking
notes and will post pictures when I get started.

Unrelated request: suggestions for non-slip mat for the bow. It
should be removable, drain well, non-marring. Durability and ease of
storage are minor concerns. Also, the edges could be anchored to the
bases of the bow rail supports. Just so no one needs to ask, this
would not be used while underway; the boat serves a raft much of the
time, and my wife will be in her second and third trimester this
summer. I'm therefore trying to make the boat as easy to get around on
as possible.

My sincere thanks to all of you.

Kirk Suffka.