Check your stem-head fitting

[wooslehunter]

Just a note as a warning.

I checked the stem-head fitting as a matter of course during the winter lay-up. I found a couple of small cracks. I've just given it to a mate who's a welder to fix. The response was not good and ignoring the swearies, the man was amazed the mast had stayed up at all.

The original welding was done simply by placing the stainless sheets together, running a torch along the join and then polishing out. To me it looked OK but to a proper welder ..........*****.

The point he made was that there was no fillet at all due to no welding rod being used during the original fabrication. The polishing process had thinned the metal out even more.

Clearly the fitting was just about good enough for the job since the mast didn't fall but just a warning - if yours is similar, check for cracks.

Dave

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[snowleopard]

many people won't trust a weld anywhere critical in a rig. if a failure of any single weld would cause the mast to come down it should be replaced or reinforced with solid metal.

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[Birdseye]

I assume that you dont use cars, or planes, or bridges, or trains...............

The advice to check the stainless fittings is good, but the opinions of a welder on engineering design doesnt really carry a lot of weight in my book. I would be much more concerned about the cracking and its origins. Is the forestay properly articulated?

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[30boat]

You can get a perfectly satisfactory weld without using filler rod providing the base metal is thick enough to leave enough metal to take the stresses that will be experienced in use.Many of the very neat welds that we see in boats are done this way.In fact that's why they're so neat.Most of the welding today is done by the TIG process wich is very suitable for this kind of joints.In highly stressed areas the edges should be bevelled and the chanel that results is then filled with weld.

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[Guest]

Another point to watch ...

Many later stemhead fittings are without the vertical securing tang that resists vertical pull of the stay. EG - Centaurs etc. where the stemhead fitting is basically a flat plate and just curls over the hull/deck joint.
Over time they DO pull up and the deck takes a hell of a load over those years .......


<hr width=100% size=1>Nigel ...
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[Guest]

Nearly all fittings are

welded ...... how do you get a vertical blade for fitting your forestay to ? How do you get the vertical tang, other angles etc. ------- nearly all stemhead fittings have welded sections carrying loads.


<hr width=100% size=1>Nigel ...
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[chriscallender]

Re: Another point to watch ...

Exactly that happened on my boat - quite frightening how bad it was when I took the stemhead fitting off. Actually because of the forestay being fitted to the back part of the fitting, the back had been pulled up and the front end had pivoted downwards.

So far I solved that by reinforcing the deck at that point and no signs of cracking so I think my brick shithouse (plywood, glass + stainless plate) repair is good enough - but for security I am also going to weld in a vertical tang the next time the mast is unstepped.


Anyway it would be a good idea to check if you have one of those flat plate designs.

Chris

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[AndyL]

Had the same and

fixed it this way

http://www.cheoyleeassociation.com/RestorationIssues/bowrollers.htm

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[Guest]

Re: Another point to watch ...

What about leading your stay to the FRONT/ mid point of the fitting ? That way you'll cure 2 birds with stone .... put the vertical load at the better part of the fitting and increase the power of the foresail a minute amount !


<hr width=100% size=1>Nigel ...
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[Mhvoiceuk]

Re: Another point to watch ...

The survey on my boat detected slight movement in the hull to deck joint and recommended that
my stem head fitting was adapted so that a metal reinforcing piece runs about eight inches down the bow and is screwed in. What's the best way to go about this? If a weld is not a good idea then do I need to get a complete stem head fitting fabricated with the reinforcing piece and anchor chain roller etc included or should I get the reinforcing piece and a plate made from one piece of metal and have the plate shaped and drilled to match the stem head fitting base plate and then bolt through them both?

Any ideas most welcome as I am a boat repair newbie.

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