Put them up on eBay. They are a piece of vee shaped hard plastic that
you attach to the front part of the keel on a powerboat to protect from
damage when beaching. I have one and they work exacly as advertised.

http://www.keelshield.com/
and
http://www.hambys.com/

are the first two manufacturers that come up when I googled "Keel
Protector". This should give you a better idea as to what they are and
how much they cost. Put it up on eBay for 75% of retail and a
reasonable shipping fee and they should sell right away.