J/30 Class Association

Hull Construction Details

Posted By: RobC222

Hull Construction Details - 09/29/08 11:53 PM

Can anyone advise on the construction details in the area of the prop strut? I have what appear to be some small stress cracks around what looks like a 4" X 7" mounting plate/base of the prop strut, and another 3" crack on the centerline about 4" behind the strut.

Is there in fact a rectangular plate attached to the strut embedded in the glass? Is there any coring in this area, or is it solid glass? Has anyone else see these small cracks? Assume they are only in the gelcoat, but I am wondering if I should grind into them to see if they go into the laminate.

Any advise is appreciated.
Posted By: sonskyn

Re: Hull Construction Details - 09/30/08 12:56 AM

The strut has a retangular plate that is thru bolted in a recess in the hull and covered with fairing compound that can safely be grinded away to expose the plate. I did just that at the beginning of the season, tightened the mounting bolts and reglassed the plate with epoxy and matt. Finished task before fairing can be seen at http://bp3.blogger.com/_lkgJ09tvrwg/SAPMI8WjLqI/AAAAAAAAAIc/QnvcNe5OE7k/s1600-h/IMG_0150.jpg
Posted By: Rhapsody #348

Re: Hull Construction Details - 09/30/08 02:24 AM

Below is an excerpt from a previous post I made a while back. Do you have a 1" shaft? It may have been changed, thus the line around the strut mounting plate.


I met the original owner this summer and he indicated the boat (Hull #348 originally named Tontine in 1981) was built with a 3/4" shaft, but he had heard of other owners complaining of "shaft whip" vibration, so he convinced Everett Pearson to change the shaft. He said that the day before he took delivery that TPI cut out the old strut, and glassed in a new one. This explains why I have a 9" square seam line above the strut inside.

I ground down the crack at the seem and found they were cosmetic. I layed up some resin and glass cloth to cover the crack just in case.

[This message has been edited by Rhapsody #348 (edited 09-29-2008).]
Posted By: HHSA

Re: Hull Construction Details - 09/30/08 01:52 PM

I had the same cracks around my strut this year too. I ground them out an used West Systems and 406 filler to fill them back in and fair them out. It worked great and when I hauled her out this fall there was no cracking visible around the strut.

Velocity Girl
#278
HHSA
Posted By: RobC222

Re: Hull Construction Details - 09/30/08 05:45 PM

Thanks for the info, and especially the photo. Takes away my trepidation about grinding into the material near the strut!
Posted By: mango madness

Re: Hull Construction Details - 10/02/08 12:15 AM

Mines all cracked. Fix it when I pull it.

I'm still pissed at the doghouse cracks near the chainplate though. I'm surprised no one can relate.
Posted By: SCampbell

Re: Hull Construction Details - 10/02/08 03:00 PM

I have a couple of photos of the strut removed and the hull mating surface. My sister ship in the harbor underwent this repair a couple of summers ago.
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