river typed With waders, you can easily swim if they are filled with
water, with any
amount of water in them. In fact, its a bit easier to move if they have

large volumes of water in them, as the waders don't constrict your body
so
much. HOWEVER (and this is a big however), you cannot overappreciate
how
hard it is to climb out of the water with waders that are even
half-full of
water! I was completely unable to climb up the ladder out of the
shallow end
of the pool, and also completely unable to lay on my belly on the edge
of
the pool and roll onto land, which is the motion someone would use to
get
back in a raft. I could not even sit on the edge of the pool and lift
one
leg out of the water.

I can tell you from real experience that a flooded drysuit does not
effect your bouyancy, but it makes it very difficult to swim in
current. The problem is that you still have to overcome the moment the
additional weight of the water, think about swimming the length of a
pool with about 20 or 30 lbs of extra weight.

A drysuit is still well worth taking the chance of a flooded suit,
which generally only happens if you do something really stupid like
leave the relief zipper open. The addded safety under cold water and
weather paddling conditions are tremendous.