Please lads..the keel was inert to all intents and purposes,Alain died at sea I seem too remember years later,(I know Tabarly fell overboard in the Irish Sea at night..and he was the advocate of NOT wearing a saftey harness).I also seem to recall the uranium was sold and maybe replaced with something else........What do I know I was only there far better to Wikopedia it ..Nite Nite
Back to the OP. Iron does rust and unfortunately expands with the rust products. So a GRP keel filled with Iron punchings or similar can rust and expand so splitting the GRP keel. A cast iron keel with paint treatment inevitably seems to rust. The rust products pop off the anti foul paint so giving premature fouling.
Lead while more expensive is more inert. Fine for inside GRP fin and Ok for exposed lead (with antimonyfor strength).
So if the OP is looking at a boat to buy. Cast iron keels are tough and the iron can be treated with epoxy to give reasonable protection between repaint but expect to retreat each winter. good luck olewill
Bertie Reed's Allied Bank had a depleted Uranium keel too. Rodger Martin design IIRC.
Downside of DU, tungsten, gold etc (anybody else remember Desmond Bagley's book The Golden Keel?) or ununpentium - the new element that's just been announced, although having a keel that auto destructs is probably not a good idea - is that most rating rules ban it. E.g., IRC rule 19.4 In the construction of hull appendages, no material with specific gravity greater than 11.3 is permitted.
Means you can't go and race it. Might not matter to some, of course, but something tells me that the sorts of people willing to fork out for a DU keel are probably competitive, racing types.
Last edited by Keen_Ed; 29-08-13 at 07:10.
Another advantage of lead over iron is that for the same righting moment you can have a shallower keel. Conversely if you want a deep keel you get less wetted surface area with lead cf iron.
Next time, it'll all be different.