Keel junction crack

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Postby Guest » Mon Sep 08, 2003 5:00 pm

Despite my boat being only 1-1/2 years old, I've noticed some small horizontal cracks on the keel surface along a line which I guess should be the "top of lead" section (section 3 of the keel plan). I've had no severe grounding since I had the boat, but anyway some rust stains have appeared. Is there anybody else who has experienced something similar ? Any ideas on how to fix and how to check keel bolts conditions and tightening to prevent major structural problems ? Also, having a French boat I'm a little confused since this "top of lead" section does not appear to be at the same elevation as stipulated on the keel official plan (it is not 800 mm above section 8 as it should be, but only 710 mm above it). Knowing that the French boats are lighter, I was wondering whether this weight saving may come also from having less lead in the keel...(I'm joking but...who knows?)
Thoughts from the experts appreciated !
Thanks in advance

Massimo Polo

Postby Guest » Tue Sep 09, 2003 5:42 am

Dear Massimo,
I too have little chracks as you describe it. I thought it happen because I put some extra lead on the bulb to make the boat stiffer and faster uwpwind (very nauty!).
I did some reinforcing by screwing ss tubes with threats on the keelbolts and some ss plates glued into the floor. Works well, but of course not a option for OD.
Anyway I feel better know because I thought I cause the problem with extra weight on the bulb.

Postby Guest » Mon Sep 15, 2003 4:06 am

I have repaired 3 J80s with cracks along the hull to lead joint. In doing so I have noticed that the "older" boats <100+- the lead is joined at the hull & fairing compound is applied, then barrior coat over that. The "newer" boat I ground into had fiberglass tape wrapped around the joint in an effort to avoid this problem. If you do not keep your keel bolts snug they flex/elongate sufficently that a hairline crack appears. If your keel is wrapped with tape at the joint then the place where the crack forms is at the edge of the tape, accounting for the fact that the crack is not at the elevation of the hull to lead joint. This is due to the small mating surfaces of the hull to lead junction & the stresses posed by the bulb keel with a serious amount of lead at the bottom with the whole lead part of the fin as a lever arm. I have watched for this recurring on Javelin ever since the repair a year ago & have had no problems. I do have the socket, extension, & breaker bar in 3/4" drive necessary to tighten the bolts, but have not done any tightening since the repair. It is possible that any movement or compression has occured although I will check it with a torque wrench after some high wind winter sailing. Just for information the nuts turned 1/4 to 1/3 turn each, including those under the lifting bar, to take them up to torque. Good luck.
Tom Gore
#36 Javelin

Postby Guest » Tue Sep 16, 2003 4:39 am

Thank you guys for your thoughts.
Tom : may I ask you how did you make the repairs ? Also, what the recommended tightening torque should be to ensure proper fixing ? (I havent been able to find it on any "user manual", either american or french).

Ciao a tutti


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