I'm thinking next winter (dry season) I want to remove the cast iron keel and replace with lead.....has anyone got any idea where I can buy a new keel...?
For what sort of yacht? Do you have a budget?
I replaced the lead fin keel on my Adams 8 a few years ago with a fin and bulb. It was a bloody big job and not cheap. I'm glad I did it but I'm not sure if I'd do it twice...
There are non ferrous foundries that specialise keel casting, it may be possible there is a keel out there that could go close to fitting your hull.
The next problem I see is matching the keel bolt pattern, in a lead keel the bolts are cast in situ.
Finally, will your existing keel mounting structure be strong enough to absorb the extra weight without unduly stressing the hull, given that cast iron has an SG of anywhere between 6800kg to 7800kg/cu.m and lead is 11340kg/cu.m
The disparity of 1000kg in the cast iron is dependent on the actual ingredients of the iron.
What do you want to achieve with this? Do you want to improve a racing boat out stiffen a cruising boat? If its just a cruiser you don't need to go to the expense and effort. Just volt done lead to the bottom of the keel, isolated electrically.
