J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment J 30 bulkhead technical discussion

to all who were following this:

I was looking at the gear from Hull #420 yesterday. Ted has the Chainplates, the plastic/fiber backing plates with bolts. They appear to be in good condition. You can reach him at tkaper6862@aol.com or through his post on the for sale section of forum.

LUMPY

Nice pear finally went on her shakedown sail today. Boat is stiff and fast!!

Last year I noticed a crack in the bulkhead that extends out from the starboard chainplate approx 1-1/2 inches out. Fearing a saturated bulkhead and a major structural problem, I removed the chainplate this spring. There was certainly some major staining from water but I was surprised and releived to learn that the bulkhead was dry. With an awl, we probed each bolt hole and determined the bulkhead to be solid and dry.
Regardless, the crack is severe and goes completely thru the bulkhead. it propogates from the top inner bolt hole traversing slightly up and outward.
We will, of course grind out and fiberglass the crack on both sides. But further, we now have an oversized chainplate designed along with a matching backup plate. The oversized plate will carry additonal bolts and we hope, spread the load over a greater area of the bulkhead. Don't know what caused the crack other than sheer load on the shrouds so we're hoping the larger chainplate will add some strength and let us feel better in any severe weather situations

The oversized chainplate was drawn up in Solid Works and thus it is availabelin in a solid model and in 2D. If anyone is interested and wants a copy, let me know

Hi
On conundrum we are repairing the entire area of the port bulkhead from the deck to the bottom of the inside cabinet of the head. About 12 x30.
The plywood is all delaminated. We will replace with glass and retab it to the hull. The chainplates show no signs of fatigue. The main cabin side shows only a slight stain. The deck has been recored and there was a 3 in rradius of rot around the chainplate. The starboard side bulkhead is dry. The staining is greater indicating the water escaped the bulkhead and travelled the outdide of it. This will make 484 a new boat. Hope we can go sailing soon

Update on Nice Pear. No motion detected on the crack in my bulkhead. I purposely did NOT glass in the crack, but filled it with a mixture of epoxy mixed with hi density filler. This way I can monitor the stresses in the bulkhead. Nothing is moving so far, however, I am keeping track of the bolt tightness. I filled the bulkhead with Get Rot, and epoxy and so far nothing is moving. Some very strong suggestions. Anyone still sailing with the original shrouds should replace them. Suggest the Hall open body turnbuckles. Strongly suggest replacing the chainplates with larger chainplates using 316 grade stainless. Russ has the idea. Bad idea to reuse the stainless that came with the boat as it is 302 grade which has LOTS of ferrite in the alloy. They are also too small to take the loads. Finally, anyone who sails with 1800 lbs on the rig is crazy. My settings are currently 1300 lbs on the uppers and 1100 on the lowers. Been out in 20+ and NO slack observed in the leeward shrouds. When the rig is at the correct tension, the lowers should be just "kissing" slackness. I believe this is not helping the bulkhead situation in our boats. In 15 kts we were both higher and faster than the other '30 in our area. I suspect that the proper "base setting" is around 1100 on uppers and 900 on lowers, with 1500 uppers 1500 lowers the "storm setting" that should be reduced when the boat is put away. Overtensioning the rigs may be why the J-30s are getting a bad rap in light air. Tight rigs are certaintly not helping the bulkhead problems. The swept back spreader rigs that Rod made famous are great for getting rid of running backstays, however, a fractional sail plan still requires management of the mast shape for the conditions. Adjustment of the shrouds between races is the compromise.

The chainplates were removed on mine (USA 139) and the deck was redone on the topsides. All completely dry now, but I need to reinstall my chainplates. Any advice on this process?

I'm assuming you left about an 1/8" all the way around the plates when you redid the core area were the chain plates go thru the deck If so all you need to do is install te plates then pump the area full of silicone which will flex with the boat underload then put the caps on with a good bed of the silcone

You should be good to go with that for a couple of years