Hit a rock today...

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Analgesic

So, last year I (actually a new sailing friend at the helm) hit a rock going 3 or 4 knots, very loud bang, no grinding and no new water in the bilge  but I did haul the boat the next day and the fiberglass inspector said the rotational torque weakened the support areas of the hull surrounding the keel attachment area fore and aft which the surveyor agreed with.  $18,000 insurance dollars later the areas were ground down and then built back up, stronger than new I was told.  In addition, there was a baseball size chunk missing from the leading edge of my wing keel which needed a straight forward repair.  It all took about 6 weeks out of my Summer sailing season.  My main thought is that I'm glad I didn't assume everything was okay from the lack of bilge water coming in and sail hard putting normal lateral stress on the keel. 
Brian McPhillips
Brian McPhillips  1988 #584  M25XP

Steve Weiss

Quote from: Analgesic on September 18, 2013, 03:16:17 PM
So, last year I (actually a new sailing friend at the helm) hit a rock going 3 or 4 knots, very loud bang, no grinding and no new water in the bilge  but I did haul the boat the next day and the fiberglass inspector said the rotational torque weakened the support areas of the hull surrounding the keel attachment area fore and aft which the surveyor agreed with.  $18,000 insurance dollars later the areas were ground down and then built back up, stronger than new I was told.  In addition, there was a baseball size chunk missing from the leading edge of my wing keel which needed a straight forward repair.  It all took about 6 weeks out of my Summer sailing season.  My main thought is that I'm glad I didn't assume everything was okay from the lack of bilge water coming in and sail hard putting normal lateral stress on the keel. 
Brian McPhillips

Yikes.

Indian Falls

When I dropped and re-bedded my keel 2 seasons ago I was surprised how thin the floor of the bilge is.  I made large backer plates and installed them under the washers just to make me feel better.  I would throw a wrench on the nuts and see if you "get anything" on them.  Some will say you can't check them in the water but if you look at it, you've got 9 bolts holding 5,000lbs, that's under 600 lbs each, and the rated strength of that threaded rod exceeds 10,000 lbs.. so go ahead and check them,  the keel is hanging there anyway.  After my rebedding project I checked the torque often to see if the 5200 was squeezing down over time. It wasn't.  After a winter, still no detectable changes.  Whenever I contact the mud, sand bar in our harbor I check them.  I'm not seeing any loosening.  However a big rock is another matter.  Best of luck!
Dan & Dar
s/v Resolution, 1990 C34 997
We have enough youth: how about a fountain of "smart"?

Steve Weiss

Quote from: Indian Falls on September 20, 2013, 07:10:56 AM
When I dropped and re-bedded my keel 2 seasons ago I was surprised how thin the floor of the bilge is.  I made large backer plates and installed them under the washers just to make me feel better.  I would throw a wrench on the nuts and see if you "get anything" on them.  Some will say you can't check them in the water but if you look at it, you've got 9 bolts holding 5,000lbs, that's under 600 lbs each, and the rated strength of that threaded rod exceeds 10,000 lbs.. so go ahead and check them,  the keel is hanging there anyway.  After my rebedding project I checked the torque often to see if the 5200 was squeezing down over time. It wasn't.  After a winter, still no detectable changes.  Whenever I contact the mud, sand bar in our harbor I check them.  I'm not seeing any loosening.  However a big rock is another matter.  Best of luck!

Thanks, that's good information to know. The backing plates sound like a good idea if I ever want (or need) to re-bed the keel.

BillG

There is a great article by Don Casey in October's edition of "Sail" magazine on keel damage.
Bill
Rock Hall, MD

Steve Weiss

Quote from: BillG on September 21, 2013, 06:30:08 AM
There is a great article by Don Casey in October's edition of "Sail" magazine on keel damage.

It just arrived yesterday so I guess I'll be checking that out.

mainesail

Quote from: Indian Falls on September 20, 2013, 07:10:56 AM
When I dropped and re-bedded my keel 2 seasons ago I was surprised how thin the floor of the bilge is.  I made large backer plates and installed them under the washers just to make me feel better.  I would throw a wrench on the nuts and see if you "get anything" on them.  Some will say you can't check them in the water but if you look at it, you've got 9 bolts holding 5,000lbs, that's under 600 lbs each, and the rated strength of that threaded rod exceeds 10,000 lbs.. so go ahead and check them,  the keel is hanging there anyway.  After my rebedding project I checked the torque often to see if the 5200 was squeezing down over time. It wasn't.  After a winter, still no detectable changes.  Whenever I contact the mud, sand bar in our harbor I check them.  I'm not seeing any loosening.  However a big rock is another matter.  Best of luck!

How thick on the 1990's boats? Our C-30 was pretty thin but cored with plywood.. I just saw a Hunter 340 with the keel off and the keel stub was well over an inch thick of solid glass....
-Maine Sail
Casco Bay, ME
Boat - CS-36T

https://marinehowto.com/

Indian Falls

#22
I did not measure.
It looked to be about an inch but less than 2.
In the center compartment it wasn't as thick an 1/8" drill bit is long.
I drilled 4 air holes to help the 5200 make 100% fill in the between the keel step and the keel top.

Dan & Dar
s/v Resolution, 1990 C34 997
We have enough youth: how about a fountain of "smart"?