Old as Dirt!
Join Date: Nov 2008
Location: Tampa Bay Area
Thanked 184 Times in 174 Posts
Rep Power: 11
Hi all - thanks for the help. I can now answer my own question. There are 14 number 20mm bolts holding my 345 keel on. They looked awful from a visual inspection of each each bolt head. They are not stainless steel and salt water had got under the sealant covering the bolts and they looked as if half the head had corroded away. However, on cleaning all of the sealant off they looked in much better condition than I (and the boatyard) thought. All were checked for tightness - which they were and there is no sign of seepage at the keel joint. I struggled to remove a bolt for inspection, but when I managed this (I had a 1 meter long socket bar) the bolt was found to be in as new condition.
I cleaned up all of the heads and have covered them in clear epoxy.
Good News and Good for You!
The trick for longevity is to keep the bolts as free from exposure to salt (or any) water as possible. Keep an eye on the epoxy. I just replace 8 of 16 keel bolts (20mm x 70mm and darned expensive!!!) with corroded heads and all proved fine once extracted (which required a 4' breaker bar!). I coated the new bolts with 4 coats of Petit "Rust-Lock" epoxy primer and shall be more diligent about keeping them dry in future.
For those confronted with similar needs on Bene's, if there is no evidence of water penetration once the old bolts are extracted, the new bolts screw in dry with a tad of sealant around the shaft under the heads and, if the galvanized bolts, which are preferred, should be torqued to an average of 145 foot lbs (but no less than 95 ft lbs for bolts in awkward locations).
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."