Bent Mast Repair

[Fiveslide]

I picked up this sailing dinghy for a song. Trouble is a storm flipped it from its trailer and it landed on the mast. It was still upside down when I went to pick it up.

See the attached photo for a look at the bend. It is roughly 5 feet below the masthead and a foot or so above the shrouds and forestay. It is only bent side to side, not front to back. This section of mast is unstayed so needs to be strong enough to stand up against a small bit of sail area with no support.

First, I think I'm going to cut something in the shape of the inside of the mast cross section and put it on a rod to send down the inside of the mast to see if I can pop the dent out. That should get it pretty straight, then with a little more effort get it as straight as possible. I've access to a machine shop so I think I will roll a small sheet of aluminum to match the compound curve of the outside front and sides of the mast, to be welded or riveted in place and covering about a foot or more above and below the old dent. I hope I've explained myself well enough so you have an idea what I'm going to try. Basically I plan on straightening it and putting a fitted piece of aluminum on it.

I see my other options as being... buy a new mast for $600+ if I can find the exact cross section and reuse the other hatdware. Halyards are internal so there will be a little more work getting a new mast ready for the boat.
Or...Buy a small section of mast to be welded to the shortened mast after I cut off the damaged section. Both of these options are entirely dependent on me being able to find a matching cross section.

As always, I'm here for your advice and wisdom. Any other ideas?

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[skipmac]

Hard to tell from the photos but if the mast has a kink or wrinkle at the bent spot the straightening is definitely out as a good as new repair. Even without, that's a pretty big bend and straightening may leave weak spot.

Best way to repair is to use an internal sleeve. Get or make a section of Al shaped like the mast to fit inside and will extend a foot or so on either side of the bend. Cut the mast at the bend, insert the sleeve on one end, rivet the two sections together, insert the other end over the sleeve and rivet the other end.

Or, since this isn't a boat you're taking offshore or a long way from home (I assume) you could just straighten, use it and if it bends further or breaks then do the sleeve repair.

[Sailmonkey]

With a dent the mast is toast. Sleeve it or run it as is, but as soon as you straighten it it's as good as a ramen noodle for strength


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[barnakiel]

Bent alloy foil cannot be easily fixed up. It will lose some strength/properties if you just bend it "back".

Bigger masts I would cut and rivet. A smaller mast I would bend back and destroy then buy a new one.

b.

[HappyMdRSailor]

The simple solution seems to live with the boat preferring a starboard tack...

All kidding aside, once you start "rebending" aluminum, you're work hardening it past its yield strength, and the original strength properties are a mere fraction of what they used to be.... Think about the last time you tried to straighten a bent antenna/camp chair/umbrella...

There's not a ton of force up there from the sail, BUT>>> I'm sure your stays attach above the bend=not good

No matter what, you are going to be replacing or shortening wire so let's see the options:

1. The easiest, and probably extremely reasonable solution is to replace the stick... definitely does not have to be the same profile ... Probably less than $500... You might even look for another crap boat, scavenge enough parts to break even, and take the hull to the dump... What are the dimensions? I'll poke around...

2. NO WELDING... makes ductile aluminum=brittle in the weld transition zone, especially with thin sections... Repairs with fasteners or riveting are preferred... Google "mast splicing"

3. How long is the bent section? Cheap is cutting it out and shortening... (hopefully not too short as in now you have a set of sails that don't fit) Fabbing an interior splice sleeve, fastening or riveting in place... Finding a length of the original section and splicing that on is the best, but more expensive route...

UN-prisine day sailors are a hoot... not having to lose your cool about a bump, scratch etc... I got one... LOVE IT!

[Fiveslide]

Originally Posted by HappyMdRSailor

There's not a ton of force up there from the sail, BUT>>> I'm sure your stays attach above the bend=not good

Actually, no, the bend is between the stays and the masthead. That's what made me think bending back may be good enough for now. We are only talking 8 sf of sail area, at most. And being above the stays, I think worst case it bends again and/or snaps, and the top 4 feet hang on by the main, rig stays up.

The boat is in excellent shape and a new mast is certainly practicle, financially. I'm just itching to sail it tomorrow.

Forcasted winds 5-10.

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[monte]

Only 8sq ft but also quite a bit of tension from the leech of the sail. I'd bend it back, go for a sail, maybe put a reeling point in the main 5' up if it doesn't already have one

[HappyMdRSailor]

Originally Posted by Fiveslide

Actually, no, the bend is between the stays and the masthead. That's what made me think bending back may be good enough for now. We are only talking 8 sf of sail area, at most. And being above the stays, I think worst case it bends again and/or snaps, and the top 4 feet hang on by the main, rig stays up.

The boat is in excellent shape and a new mast is certainly practicle, financially. I'm just itching to sail it tomorrow.

Forcasted winds 5-10.

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Oh man.... I would go for the straightening route attempt FOR SURE then!!!

I totally missed the awesome description in your OP/para 2.... Imma dope...

Can you get the masthead cap off???
Thinking of a wood block slightly smaller than the inside on a 5' rod/2x4... Pound inside while the mast is tensioned with tie down straps?

[Fiveslide]

Originally Posted by HappyMdRSailor

Oh man.... I would go for the straightening route attempt FOR SURE then!!!

I totally missed the awesome description in your OP/para 2.... Imma dope...

Can you get the masthead cap off???
Thinking of a wood block slightly smaller than the inside on a 5' rod/2x4... Pound inside while the mast is tensioned with tie down straps?

Precisely my plan. I knew I'd get the go-ahead from a fellow McGuyverer.

Thank you, monte, leech tension is a variable not considered until now. Think I'll just sail of the wind a bit to keep the mainsheet a little loose, leave the vang at home.

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[HappyMdRSailor]

Originally Posted by Fiveslide

Precisely my plan. I knew I'd get the go-ahead from a fellow McGuyverer.

Thank you, monte, leech tension is a variable not considered until now. Think I'll just sail of the wind a bit to keep the mainsheet a little loose, leave the vang at home.

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Oh Hell yea...

How about ...

Couple of sawhorses with a solid platform between... Placed "just above" the bend... One sawhorse at the foot... One of them trucker size ratchet straps pulling down at the masthead using the weight of the mast for the straightening force...

A little tension on the strap... and tap... tapp... tapppp your inside block???

[Cheechako]

From what I can tell that is a pretty bad bend. Is that a tapered mast? Get a good spar guy or welder to sleeve it and repair it.

[Fiveslide]

I'd like all of you who posted about making a proper repair to know that you are spot on and a proper job will be done, in the near future, I assure you. Probably order a new stick within a couple of weeks. Your advice is not being ignored.

But this is about a need, a need to sail this newly acquired boat on this beautiful holiday weekend.

Happy, it's like you are in my head, like you can see my future. Does it work?

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[HappyMdRSailor]

Originally Posted by Fiveslide

I'd like all of you who posted about making a proper repair to know that you are spot on and a proper job will be done, in the near future, I assure you. Probably order a new stick within a couple of weeks. Your advice is not being ignored.

But this is about a need, a need to sail this newly acquired boat on this beautiful holiday weekend.

Happy, it's like you are in my head, like you can see my future. Does it work?

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***squinting***

Oh I'm sayin' HELL YEA it worked!

3 beers, and you can hardly notice the dip to port up there...Good thing I took the extra time to make sure the bolt would slide smoothly past the kink... It would have totally blown donkey if I had to take the stick down with the main stuck...

[Jim Cate]

A sailing story... but a true one!

Many years ago I had a Catalina 22 which we raced under SYRA in San Francisco bay.
One event was a two-race weekend out of the Saint Francis YC (a very high end sort of outfit). At the start of the Saturday race, a spreader broke and the mast bent off sideways. RATS! We motored back into the YC's dock, took down the mast and stuck it into a big steel ring that was part of a big piling. A bit of grunting and swearing and it was sorta straight again, but with a big dent on the side of the extrusion. All the blue blazer types were laughing at us whilst sipping their morning Bloody Marys. I sent a crewman off to the hardware store for some DIY aluminium tube and a bit of dowel that fit tightly inside the tube, and we made up a replacement spreader. Stuck the mast back on the boat and "tuned" the rig. Looked pretty agricultural, it did! More laughter ensued.

Sunday we went out and won the race.

We used that mast for months until I shamed Frank Butler into replacing the extrusion.

So, for the OP, I think that if you can bend it back into some semblance of straightness it will work just fine. You have little to loose by trying. All of these chaps who are saying that it will fail haven't really thought it through, or just don't understand the loads on a mast very well...

Good luck, and enjoy your new boat!

Jim

[Fiveslide]

Well, Happy is full of it, the mission was a failure. The mast split at the dent during straightening.

New plan is saw it off just below the deformed section, reattach the masthead and sail tomorrow with the first reef in.

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