Does This Warrant a New Mast?

[Cheechako]

That must be a weld to extend the mast. or a weird paint bubble? Maybe someone already put an extension on the mast due to a corroded bottom?

[Peregrine1983]

Hi Seaplane, can you post a better photo? Using the flash will get a less grainy exposure and it will be much easier to see if it's a paint phenomenon or something else.

[captlloyd]

As someone who has been welding for 65 years I can tell you it looks like a section has already been welded on. As you grow older sometimes it is hard to tell where the seam is you’re welding and you go off on a walkabout. That’s what looks Like happened here. Ha ! Hard to believe a mast section would buckle like that.

[a64pilot]

To me, it looks exactly like a tube that has failed on compression does, not saying that’s what it is, but that is what a tube that has failed under a compression load looks like.

[Cheechako]

Originally Posted by a64pilot

To me, it looks exactly like a tube that has failed on compression does, not saying that’s what it is, but that is what a tube that has failed under a compression load looks like.

Yeah, it does look like it, but I would expect to see a far bigger bulge in that instance. I spent 30 years in aerospace bulge forming, compression forming etc. I would have been very hard pressed trying to do it like that.... unless that mast is only 1/32" thick!

[a64pilot]

Originally Posted by Cheechako

Yeah, it does look like it, but I would expect to see a far bigger bulge in that instance. I spent 30 years in aerospace bulge forming, compression forming etc. I would have been very hard pressed trying to do it like that.... unless that mast is only 1/32" thick!

Or thinned by corrosion. Hopefully not, but it does look strange

[CF32907]

CaptVR here,
Indeed very odd. After inspecting 100's of mast bases over 50 years, I can say, I never seen one exactly like this. To start with, you never mentioned if any of your standing rigging got at all slack. Nor who has tuned it in the past. From looking at the pic, I would say that someone had welded a new section on the mast base and used the wrong alloy aluminum in there mig gun. It is not uncommon to see corrosion like that. Say the spar is 6061t6 and it was welded with 4303. Moisture travels around the weld under the paint and in the bilge area that is filled with many types of electrolites and corrosion starts. But this and all comments you received is speculation, some accurate some not so. Clean the paint off for a good visual. Go to Horrible Freight, by a $75. bore-a-scope and look inside the mast in that area. Then you can make a good determination of the problem. You will find 100's of uses for a bore-a-scope, boat, camper, home, etc. But in the good old days, to be 100% sure, and any corrections needed. Pull the spar, not that big of deal.
Hope this gave a little professional insight, happy sailing to all.
Capt. Vince Rakstis, Ret. MS St.Petersburg, Fl.

[CF32907]

CaptVR here again. I'm very sorry, I never did answer your question. If the mast as a whole is sound and in good condition. The mast base can be fixed with little problem.
A wood base step can be made out of white oak and saturated with coupranol for a good base extension, the cheapest fix. Better than that, make it out of Purple Heart wood and it will outlive the boat, cost a bit more than oak . Of course, you could also cut off the affected area and weld in a new section. That would be the most expensive fix.But for your question, no a new mast is not required..
Capt. Vince Rakstis, Ret.MS St.Petersburg, Fl.

[Jim Cate]

Originally Posted by a64pilot

To me, it looks exactly like a tube that has failed on compression does, not saying that’s what it is, but that is what a tube that has failed under a compression load looks like.

With respect, 64, for that to be true, would not the tube wall thickness need to be very thin? the bulge that would result from compressive failure on typical mast walls would be far bigger... not that narrow little ridge. And as someone posted earlier, it sure looks like a weld line.

Also consider that the mast appears to be quite straight in the flaw area. If it failed from compression I'd be surprised to see that .

But meanwhile, simply scraping the paint off the area will clear up whether it is a weld line!

Jim

[a64pilot]

Jim, I’m not saying it has failed, but a tube that has looks a lot like that.
I can’t imagine it failing like that, a mast is in compression that’s true but it’s not in pure compression, usually one side is loaded a whole lot higher than the other, and then you wouldn’t get a straight down collapse, it would buckle to the side.
I’ve never seen a mast fail, but I bet you racers have, and I bet it wasn’t a straight down collapse, but a buckle to the side.
Only logical conclusion is that it’s a weld, but if it is, why isn’t it straight?

[LongRange]

That cable entry hole looks significantly bigger than it really needs to be, and is that a ragged edge on its bottom left quadrant?

Overall, that mast seems worthy of close inspection.

[a64pilot]

Ref ragged holes, I had a Professional well known highly thought of rigging shop butcher my mast with a drill bit drilling several holes to make one bigger one. Absolute shoddy work, but I guess as a mast is in compression they get away with it, but I come from a school that says you clean up holes to make sure there are no stress risers.

[skenn_ie]

If it is creased, see if you can get a standard casting to fit the profile, insert it and spacer to bring it back to height.

[merrydolphin]

Could a lightning strike do anything like this? I’ve seen it do some strange stuff.

[Wallaby]

Originally Posted by merrydolphin

Could a lightning strike do anything like this? I’ve seen it do some strange stuff.

As in heating the aluminum to the point of softening it? If it was lightning coming down the mast, there has to be an exit from the mast to a conductor, then to the water. I suspect for enough heat to melt this much metal, there's be major scorching of the mast plus the surrounding fiberglass. The OP needs to either scrape off the surface or look inside the mast. It could easily be a crummy weld from long ago,