Galling

[Neo]

Originally Posted by s/v Jedi

The torque adjustment for lubricationshould be applied to the torques published for just the type of metal of the DRY and CLEAN fastener. NOT to a torque spec from a boat manufacturer, who might or might not already have adjusted for an unknown lubricant.

We have a 3,800 lb lead keel held on with four 1" and six 3/4" stainless bolts. The hull is solid FRP. It was manufactured by Pearson, who is no longer in business.

The boat had a hard grounding so I want to remove, inspect and retorque the bolts one by one. I've read every thread I can find, but I still don't know what torque to use, or if I should do this on the hard or in the water.

[Neo]

The online engineers handbook gives 1582 inch-lbs (132ftlb) for 3/4" stainless bolt (clean dry), and Pearson table gives 125 ftlb. But pearson specs don't specify boat or bolt material, and I'm pretty sure some of the smaller Pearsons had steel bolts.

[Neo]

So, if Pearson used oil (0.8) x 132ftlb, that would be 105 ftlb.

[s/v Jedi]

I'm not an expert but think you need to do this on the hard and just use the 132ft/lb clean dry torque for stainless steel bolts.

Use a magnet to find if it is regular steel or stainless steel. Compare with a bolt same diameter of steel and another one from stainless steel. Compare those two with the one in your keel using the magnet.

No need to try to find out what or how Pierson did it: just determine using handbook and materials at hand.

p.s. I think Pierson is part of TPI now.

[Neo]

Originally Posted by s/v Jedi

I'm not an expert but think you need to do this on the hard and just use the 132ft/lb clean dry torque for stainless steel bolts.

Use a magnet to find if it is regular steel or stainless steel. Compare with a bolt same diameter of steel and another one from stainless steel. Compare those two with the one in your keel using the magnet.

No need to try to find out what or how Pierson did it: just determine using handbook and materials at hand.

p.s. I think Pierson is part of TPI now.

I'm slowly inching my way towards a decision. I may not be in the ballpark but at least now I know where the ballpark is. I am inclined to torque it "clean and dry" in order to remove as many variables as possible. I have no expertise or experience, a deadly combination. If I do lubricate, it will be with a light oil like wd40, which has a lube factor of 0.8, to prevent galling.

I'm using Life Kaulk as bedding material, letting it set overnight before torquing. I think I'll treat with a little penetrating oil after, to displace any moisture, and coat with marine grease.

[Neo]

Originally Posted by Maine Sail

You might consider re-passavating them. The wire brush will leave behind residue which will eventually rust. Citric acid works but I prefer Spotless Stainless.

Thanks, I'll do that, especially since I can't bring myself to use TefGel.