Oh well, I do not scuba dive. I should have asked first asked
regarding . . we have ample lead weights . . . as soft sided "bean
bag" weights") The soft sided bean bag weights would work well
beneath a kayak seat (and there is a scuba dive shop one mile from my
house). I saw the solid lead weight belts for scuba divers. I never
knew that scuba divers used bean bag weights. Oh well, maybe next
time (the purge valves used by scuba divers work well on larger
drybags - the type of drybags I used for canoeing).

I don't know that I would want to leave it in full time

I agree completely. This is why lead blankets or even better, your
ideal of lead bean bags, is desirable. Longer term trips, yes, day
trips, no.

And yes, depleted uranium would be even better as depleted uranium is
a denser metal than lead. As there have been (thankfully) no tank
battles near my home (Minnesota U.S.A.) and therefore no leftover
destroyed tanks from any tank battle, I do not have a nearby source of
depleted uranium. Many tanks used depleted uranium for armor. Or
should I ask the nearby VFW (Veterans of Foreign Wars) post if I can
look at the tanks sometimes on display in front of their clubs ?

My wife and I are avid scuba divers and as such we have ample lead weights
(solid weights as well as soft sided "bean bag" weights). For the purpose
of figuring out the best trim for our seakayaks we often used beanbag
weights as ballast. Worked well!

I don't know that I would want to leave it in full time. It would make the
boat more stable, but also means you have to paddle and carry the extra
weight.

Thanks for the scuba diver bean bag tip.

Scott Bemis