Thank you everyone for your comments - the purpose of the eyebolt was so
that I can optionally use one of the weights as a lunch anchor on the
sailing pirogue as well as allowing me to tie the weights down when using
them as ballast. I need the ballast to compensate for the weight of my son
at the bow when solo sailing. Having them tied onto the boat also allows me
to cut them free in case of emergency rather then building them into the
boat. I was going with about 10lb weights as that is a size I should easily
be able to manage.

I might try melting the lead as several people suggest - doing it outdoors
but I suspect that using resin to cast the weights into a can might be my
final result. I have to wait for warmer weather no matter what anyway.

--
Andrew Butchart