So you call that a mast repair?? - SailNet Community
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post #1 of 10 Old 01-31-2014 Thread Starter
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So you call that a mast repair??

I recently backed out on the purchase of a real nice fixer upper of a sailboat. I already had cash in hand, it was an Albin Express on a trailer for 2k. However the last time I looked it over, I noticed that the base of the mast had evidence of damage. Someone had taken a piece of 1/4 aluminum sheet and shaped it to fit around the bottom 6 or 7 inches of the mast (in two pieces). These parts were then welded to the mast itself and all the areas where the patch had seams in it. The quality of the welds did not look too bad but I've seen better.

However what concerns me is sort of technical. The mast is a relatively thin walled extrusion that relies on it's shape for strength, and it is anodized. Both extrusion and anodization affect the hardness of the aluminum and I'm pretty sure that the extrusion alloy is harder than standard 1/4 inch plate. Especially when it formed so nicely to the shape of the mast cross section, which would indicate that the patch was unannealed, softer than the mast. In the heat affected zone of a weld the properties of all these materials is affected.

I would never trust a weld under these circumstances. I mean for me there is this great possibility of stress cracks or failure at the top of the patch where the mast meets the weld bead. If I had it to do my way I would have cut off the damaged part and modified the deck step, or fabricated a part to fill in the gap that would be secured to the mast with mechanical fasteners.

Any thoughts?? Anyone ever deal with a problem like this. It looks like someone damaged it while they were raising the mast.
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post #2 of 10 Old 01-31-2014
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Re: So you call that a mast repair??

Hard to say with out seeing it in person . The patch didn't need to be in soft cond. to shape it to the mast . Maybe a welding expert could say if the welding damaged the condition of the heat treat of the mast . But on the other hand how long has the patch been on there ? I mean if it's seen use maybe it's OK.
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post #3 of 10 Old 01-31-2014
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Re: So you call that a mast repair??

I assume the bottom of the mast sits in the bilge and corroded over time. The proper fix is to cut off the bottom of the mast and build a higher step to take up that space. The new step should be non-corrosive and not react to the aluminum.
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post #4 of 10 Old 01-31-2014
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Re: So you call that a mast repair??

Bottom of the mast. Corrosion ?

Not much flex there, just a compression load.

I would think it would be fine.
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post #5 of 10 Old 01-31-2014
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Re: So you call that a mast repair??

Mast sections can certainly be welded. The spreader bases on Isomat masts are aluminum castings that are welded to the mast. That's right in the middle of the mast section. If the patch was done well, it's probably fine.
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post #6 of 10 Old 01-31-2014
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Re: So you call that a mast repair??

Almost impossible to tell the soundness of such a repair. Start with choice of alloy & welding stick (or wire), TIG amperage, annealing.... Welding Alu is not a trivial business, and subsequent heat treating can make all the difference between a great repair & one that fails w/out warning.

That said, if the repair looks moderately competent & hasn't failed yet, it might be fine. Most (tho not all) of the force at that spot is compression, and the Express doesn't experience crazy loads with only 315sqft of sail. (Nifty boat, BTW. Much raced in England. Sails better with meat on the rail.)

You could saw off the repair & build up the deck plate to suit; or you could cast (lost wax?) a metal shoe or build a composite one to sleeve into the mast. You could also likely find a used stick suitable for that boat for around $800. Cut to length.

Buccaneer18, Grainnia
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post #7 of 10 Old 01-31-2014 Thread Starter
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Re: So you call that a mast repair??

Thanks for all the good input. If I find myself back on the market to get a boat and this one is still there, I may go for it.
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post #8 of 10 Old 01-31-2014
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Re: So you call that a mast repair??

A picture is worth a thousand words.

Bristol 31.1, San Francisco Bay
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post #9 of 10 Old 02-01-2014
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Re: So you call that a mast repair??

Welding part of a mast section is not bad unless it is poorly engineered or the welding is improperly done. Tall masts on larger boats (masts over 40' or so) are usually 2 sections, sleeved and welded at the join, as there is a transport size limit on extrusions. As posted the spreader bases are welded on some masts as are masthead fittings on some.

Without knowing how it was done or seeing a picture preferably the repair cannot be judged.

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Living aboard in Victoria Harbour
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post #10 of 10 Old 02-01-2014
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Re: So you call that a mast repair??

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Originally Posted by TQA View Post
Bottom of the mast. Corrosion ?

Not much flex there, just a compression load.

I would think it would be fine.
Mast base in compression? $2K boat? A good outboard cost more than that.

While I could talk about how I would have done it--on a $$$ boat--on a $2 boat I would be thrilled with that repair.

My guess, if the PO bothered to do such a challenging repair, rather than just cutting off a few inches and raising the step, is that perhaps ice froze in the mast and burst the section up a little ways. But I don't know.

(when asked how he reached the starting holds on a difficult rock climbing problem that clearly favored taller climbers - he was perhaps 5'5")

"Well, I just climb up to them."

by Joe Brown, English rock climber




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