Chrysler Sailors Forum

Ever since I read tnc110's comments about losing the swing keel and rolling over I've had a few nightmares. I replaced the brackets and pin on my C-22 last year. When I removed the old brackets I took one of the bolts I removed to West Marine and got new stainless ones that were the exact same size and appeared to be identical. The thing that concerns me is I failed to pay attention to hardness, etc.

When I was installing the brackets, I did manage to break/twist off a couple of bolts when I overtightened the nuts. But I think the twisting force is different that the shear force on the bolts. I believe that the bolts are made to withstand shearing forces and I am hopeful that someone with an engineering backgrond might be able to weigh in on this.

When keels have been lost, is that due to failure of the pin? I had great stainless brackets made, have a shiny new 5/8" pin and now I just have this nightmare about the bolts breaking.

Mike

Hi Mike,

I usually get my SS bolts at www.boltdepot.com or Lowes in the Hardware department.

If you applied so much pressure that the bolt broke before the 5200 cured, I'm afraid that you probably squeeze the sealant out of the bracket and might leak in the future. Never apply so much pressure on bolts! Apply enough to squeeze out an even little bit all around, let it dry, then apply some more pressure to make the seal watertight.

There are a lot of variables in your question: Bolt Tension,
Thread torque, Thread Root Area, Thread Root diameter...and it also depends on the shear load applied....static? kinetic? Also its kind of hard to compare shear force vs torsional because they are in different units of measurement.

When u broke the bolts, were they the first ones you tightened? If so I am assuming you eased up on the torque after you broke first ones? If so I would say you are fine.

If you tightened them all to about the same torque and a couple of them broke and the others didnt then I might be a little concerned.

The good thing is that even if all the bolts fail I dont see the keel being able to come out...or at least mine couldnt. The hull would fill full of water very quickly though!!!

I would say you would be ok, but I would maybe regroup this winter.

Shear force is what matters in this case, those bolts are pretty small and SS is more brittle than regular steel bolts so you have to take care not to over torque them.