Ok, I've done this twice, contemplating a third time.
The first boat was a 32 foot cedar on oak cutter
, which had a lead keel. But the owners wife at some point convinced him to add steel and cement to the bilge. Sadly he did this without tarring the bilge first and the lime in the cement ate the lignen from the oak, leaving the keel (to a depth
of 2-3 inches), the floors (completely) and the bottom of 32 consecutive pairs of ribs in a fibrous mess.
I ended up chiseling the cement and tractor bits out of the bilge with a hand sledge and a star chisel in order not to completely destroy the remains. After it was done, I solidified the keep with West System epoxy
, and soaked the floors in it as well. The ribs I repaired by splicing in 18inches of steam bent oak and then putting a 1x 1/8 stainless steel strap from keel to 30 inches up the rib
and refastening with stainless steel machine screws and nuts.
I have no idea how it worked out as I ended up going bust and lost
2nd case was an H.O. 28, built of steel and the keel can was full boiler punchings cover with about 6 inches of cement and steel mix. This time I used a Kango electric
jack hammer to bust up the mix. We then took out everything, including the water
in the punchings and weighed everything as it went over the side in buckets.
Using the waterline as an arbitrary datum I calculated the moment arm of the steel and cement mix. From that I calculated the amount of lead needed right at the bottom of the keel can, and then acquired tire weights, smelted them into ingots and packed them in. That gave me enough room to install water tanks
and a holding tank
in the keel can above the lead.
Again, I have no idea what happened with the boat, I sold it to a retired school
teacher and wasn't able to keep in touch.
My third boat, Sabre
Dance has cement and punchings. I emailed Bruce Roberts-Goodson and asked if it was possible to remove a foot of keel off the bottom if I replaced it with lead. He concurred.
At the moment the cement and steel mix appears to be in good shape, I may or may not do so. However, I will keep the keel in its original shape as the boat is heavy and I am removing as much weight as I can. I will see how she floats later this year and go from there.
It is possible but its a bloody lot of work, and you need to take the changing moment arm of the ballast into account. I'll leave it to you to decide if it's worth it or not.