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As y’all may know, Hurricane Laura did a job on our Santana 20.  In the process of blowing her off of our trailer, her mast was bent.  The bend is more of a bow than a crease.  The spring in this bend is about a foot out of true.  

Wondering if anyone has attempted to straighten a mast with this much of a bow and what luck might have had.  

If I were to try this, I suspect the method would be to support the mast on each end and apply weight gently to the point of the middle of the bow going slightly beyond center to get it reasonably straight and then finish the process when the mast is trued on the boat.  

Looking carefully at the picture, the bow can be detected.

 

image.jpeg

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Looks like the center is a foot or so under the lowers. Might be worth stepping it and seeing how much can be tuned out. 
 

never had much luck trying to unbend aluminum. 

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When 'Secret Love" was trucked East for the '84 SORC the truck driver managed to bend the top of the spar - about 12" from the tip & 2" sideways (IIRC) During the practice sails before the circuit we could not get the spar to stand straight. Ron Love (head of Sparcraft) was on the crew and sighting the mast/calling for T/B adjustments (which were below deck). No chance, regardless of how we adjusted things.  Finally in desperation  when back in the slip I spun all the T/B's down to slack, so that the tube was standing on it's own. Then the kink became visible. With no time left and out of options, we took the rig out, stripped it of gear. Found a large metal sawhorse - stuck the top of the mast under a cradle holding a Westsail 32 (immovable object), padded the sawhorse beam with sections of old tire. Put the horse right at the bend point, and slowly applied more & more force (by walking out on free end of spar & bouncing). After each bounce, would pull spar out, lay it flat & re-sight the sail track. The tube straightened out & that spar stood straight until we broke a checkstay & kinked it low down in the Bermuda race.

This was a full race spar (for it's time). Each panel was acid etched to minimal thickness between spreaders. When supported by the ends & middle it would still sag between supports

So I would try to determine the center of the bend, the ends of the bend, set supports up for those points & try to straighten it out. It un usable now, nothing to lose.

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Pick a nice warm day (can't hurt) and go with the pin the base (tree, Westsail 32, etc), well-padded sawhorse or equivilent at the point of max curvature, and a force at the masthead.  Slow and steady, with mulitple checks is the way to do this, though I'd recommend a constant force, rather than "bouncing" as longy described.  Weights hung or block and tackle, so you can gradually increase the force at the masthead, and hence the "counter-bend" 

Can't hurt to try, though I'd pull the spreaders, etc, so you don't accidently goon one of them up.

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We straightened the mast on a Pearson Electra (22', pretty similar to a Santana rig), was bent a lot more than that. Caused by hooking a lower on an immovable object in an attempt to get out of the current. Used a strongback (a piece of 12 x 12 x 10' timber that was lying about), some straps, and a car jack. The jack lets you go slow and easy. 2" wide straps to keep from denting it. The slug track was a little tight when we got done, drove a wooden wedge along it to open back up. Sailed it at least another 10 years. 

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In the olden days of metal dinghy masts we did this regularly, but always on the understanding it was a final throw of the dice, we had nothing to lose and the next step was a new rig. It usually worked. Repeated short loads, with lots of checking on progress in-between were usually more effective than just pulling hard.

As mentioned the key is to pad the pressure points to avoid introducing a new kink/dent.

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Beware of the spreader hole !!! It is a massive stress riser right where your bend is. The pole lift exit block will be somewhere close by also. Schock did a terrible job cutting these holes, leaving sharp corners . Most of the S20 masts I've seen broken, failed through one or the other of these two spots. Your bend looks to be centered around the top of the lower shroud ( another pair of holes, but round ), so there may be a kink under the shroud bolt on the inside of the bend.

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6 minutes ago, Bull City said:

Please give us an after action report.

will do jsut as soon as we both get over this head cold / upper respiratory stuff.  (Tested, not flu / not Covid) Just C R U D

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The one way to bend aluminum is called “bumping.” You take small bites that just start to yield the aluminum. You can feel it happening. As soon as you feel it stop and move the spar to bump it someplace else.  The more the smaller the better. 

I prefer to use fairly large trees and work it like a lever.  Stay cool and you can win. Get impatient and you might as well not started.

SHC

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  • 1 month later...
On 12/15/2021 at 9:52 AM, Bull City said:

Please give us an after action report.

Well, with a nice extra bow right in the middle of the bow, the old mast is history.  Anna is getting a brand new mast.  One step closer to getting her back in the water.  

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On 12/6/2021 at 10:13 AM, Feisty! said:

Beware of the spreader hole !!! It is a massive stress riser right where your bend is. The pole lift exit block will be somewhere close by also. Schock did a terrible job cutting these holes, leaving sharp corners . Most of the S20 masts I've seen broken, failed through one or the other of these two spots. Your bend looks to be centered around the top of the lower shroud ( another pair of holes, but round ), so there may be a kink under the shroud bolt on the inside of the bend.

You nailed it.  With your information, i checked the areas around the spreader holes.  The mast was kinked, right at the spreader hole pretty much right at the main bend.  I am surprised the spreader survived.  

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