The clew attachment hole in the aluminum casting at the end of our wishbone is worn and I am beginning to worry about the casting failing. I am planning to remove the casting and have the whole fill welded and re-drilled. I have managed to loosen all the screws and bolts holding the casting to the wishbone. I have not yet removed it as I thought I would ask if others have had the same issue and repaired the casting. If so could you share your experience?
Will the wishbone spars spring apart when I remove the casting? If so would lashing the two spars together work or is there a better way to hold them in place until I re-install the casting?
I suspect the casting will be stuck in the boom spars, if so is there a trick to pulling it out? rubber mallet, heat the spar tubes with a propane torch? other suggestions?
We have a Murray Cressman boom extension, I think I can remove the casting without removing the extension. Does the extension need to be removed?
IS there anything special the person doing the welding should know about the casting material?
The holes for the bolts and screws are barely wider than the shank of the screws and bolts. I suspect re-inserting the casting and aligning the holes will be a challenge. Should I apply a lubricant, machine oil to the casting before re-inserting?
Any advice or description of your experience with this task will be greatly appreciated.
Thanks,
Ed Brost
SaSeaCat, NS30-322
Sarnia Ontario
Didn’t someone like Cressman at one time make a stainless fitting that simply wrapped around the area where the worn hole is and fasten with two bolts. I am sure I saw that somewhere in this group. It was made specifically to fix this problem.
Jamie Morrison
Dexterity II
30U 225
Halifax, Nova Scotia
I had the Cressman fitting for the front… was not wild about it as it reduced the amount of aft movement … took it off and bolted a stainless plate above / below the hole with a hole for the shackle. Works just fine. I think you could do the same at the aft end of the boom as well. The casing is easy to drill so a small plate could be bolted over the elongated hole and the new hole sized so there is an exact fit for the shackle.
Welding these castings would be a challenge and removing them could be interesting! Other option is to use a lashing vs a shackle and simply protect the lashing from wear like a dock or anchor line..
Thanks, this is the type of information I am looking for. Do you have a photograph of your SS plate? Your idea and solution looks promising and less scary than pulling the casting from the wishbone.
A lashing is the correct way to fasten the clew to the wishbone. Should a disaster of some kind strike it far easier to cut through a lashing then a shackle. Just uses some 5mm Dyneema. I have used it for years with no signs of wear on the line or around the hole.
Jamie Morrison
Dexterity II
30U 225
Halifax, Nova Scotia
I have lashed the clue to the casting for the last couple of years and as a result the hole likely isn’t getting any bigger. But the forces on the aluminum casting are still there, although perhaps spread a bit better than using a shackle.
I am under the impression that if the casting failed, i.e. the hole opened up, it would be under severe conditions with very high potential for bad knock on effects. I would like to minimize that threat by somehow restoring design strength to the fitting.
Hi Ed,
If you have a Cressman extension why not just attach your clew to the extension? That’s what we do. Perhaps your extension is different than ours, which has a stainless loop top forward.
We removed both castings from our wishbone, the forward one for replacement and the aft one to repair a damaged boom tube.
Both came off easily with some gentle persuasion using a short length of 2x4 in the crotch struck delicately with a 4 lb club hammer. The spars are permanently bent and do not spring apart. We removed our extension first because it was installed by drilling and tapping into the casting, the most forward holes overlap the tubes and are drilled through them.
I would be careful about welding a casting, it might end up weaker than when you started.
Reassembly in our case was facilitated by using an old halyard as a turnbuckle to slowly line the holes up. We used lanocoat to lubricate during reassembly and protect thereafter.
Bruce Flinn 30U 399 PATIENCE Chester NS
I was under the impressing that the Sail should be lashed to the clew to avoid excess wear and also serve as a sacrificial line which will part befor the sail rips…
Mike Quill sells two stainless steel plates with bolts to remedy the elongated clew hole. Drill holes on either side of the casting then bolt them on. I did it about two years ago.
