Mystery Mast Welds - Explanation Please !

[MikeMak]

I hope someone can help me.

I'm considering the purchase of a boat but the mast has me puzzled.

Approximately 18" above the boom, it has a seam all the way around it as well as various weld spots - all very sanitary. No apparent signs of a previous dismasting.

I've never seen anything like this before. Does anyone have an explanation. Mast is by Offshore Spars. I'll try them on Monday, but in the meantime, looking for some help.

Pictures posted.

Thanks.

[Unicorn Dreams]

Good looking welds, but I wouldn't want them on my mast unless, they were done by the mast maker in the original design..

[capngeo]

It does look like it was sleeved. I'd sure want a look see inside with a borescope.

Keel or deck stepped?

[Sand crab]

On splices it is common to sleeve the inside of the mast and spot weld that. Those are the spots that you see. For some reason the mast was too short for the current use. Corrosion at the base or around fittings and attachments is one possibility so they might have cut it off and spliced it. Or maybe the mast was a short replacement and was extended. If done right a welded mast is fine. Has this withstood the test of time and miles? Looks very professional to me. Find out who did the work. I want his number just in case. BOB

[John A]

Some mast, mine included, are shipped in two sections due to their length.

[capngeo]

Originally Posted by John A

Some mast, mine included, are shipped in two sections due to their length.

True, but most of those are spliced near the middle... AND are riveted for the most part, not welded.

Welding a mast is difficult at best..... the welder who did the work in the OP was a master, and I would likely trust it no problem. My borescope statement was mostly to see if there was corrosion between the sleeve and mast, not to look at the welds, as they are not visible from the inside. The mast appears to have been anodized AFTER welding, so I would suspect it was OEM work

[MikeMak]

This mast is on a 32 foot catamaran - deck stepped.

[hellosailor]

Mike-
Don't expect them to answer the phone on Monday, unless they're open on federal holidays. Regardless of the quality of the job--I wonder if the seam, the question of a previous repair, would cause a problem on insurance survey & "pre-existing" conditions?

As mentioned some mast are shipped in two sections because a maximum shipping length ~40' is possible, and then costs skyrocket. But those masts are usually sleeved and riveted, to spread the load through the sleeve section. Welding requires much better field skills to be reliable.

[Unicorn Dreams]

Well ithe mast is short enough to be trucked one piece.

[capngeo]

Mike... look up pix of sisterships and see if there is a similar weld

[Sand crab]

Mike, how old is the cat? BOB

[MikeMak]

The boat is of 1997 vintage. I want to thank everybody who has responded so far for their input.

Is it true that this splice is at or near the area of the mast that is most under load while sailing? The weld is approximately 2 feet above the boom.

How much less would you pay for a boat with a repaired mast such as this?

[s/v 'Faith']

From the looks of the pictures, the weld is only a couple feet from the base. Unless it was done with JB weld, I would doubt that it would cause any problem at all, and if it is sleeved (as the tack welds would seem to indicate) it may actually be stronger where the hardware attaches....

I would not have an issue with it... good advice given WRT looking at pictures of (or contacting owners of) sister ships....

[Eric50]

What can be easily done as first check on the welds, is a dye penetrant test.

It takes less than one hour and will detect any (open to the outside) flaws, in particular cracks and lack of fusion and can give you a very quick answer about the weld quality and integrity.

It is easy to do, the products are cheap, provide you do it properly (specially when you remove the excess of penetrant, do not spray the solvent directly on it as most of the people do, wipe it with a solvent wet rug or use water), it will give you all the info you need at revelation.

About welding, to really find out if a weld is "fit for purpose" you have to enter to a process that is barely (not to say never) apply in such work, but more at an industrial stage.

It involves welding procedure qualification and welder qualification as per standards and codes, parameters monitoring....the real & only way to ensure that the welding will whistand the stress in service on a particular assembly.

Back to our leisure boat topic, a good visual on the weld (it sounds good on the picture, but it is only based on the picture...and we do not see 100% of the weld) and dye penetrant will be sufficent to have a decision on this mast integrity.

A good weld is as strong, at least than the parent metal, usually.

[bangkaboat]

Personally, I wouldn't touch it, as is. Unlike welded steel, a welded joint on aluminum does not have the strength of the parent material, not even close, try in the neighbourhood of 35%. I'd suggest an x-ray, first. Providing that there were no gas pockets, full penetration, no other flaws & that there was a fair bit of overlay to the inner sleeve, I'd then want to add a collar, welded top & bottom. It doesn't matter that "They do this a lot", it is still compromised. Dye penetrant won't give you the answers.