Slightly bent mast

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Slightly bent mast

Postby KingsTransom » Mon Aug 15, 2016 12:31 am

I've had the boat for about six weeks, and just now noticed that the mast is bent. The point is about half-way between the spreader brackets and the jib halyard pulley. The bend is to aft and port. I'm not too concerned about the bend itself since it is small, rather the narrowing of the slot makes me wonder if the mainsail will hang up at that point. It appears that the PO dropped the mast on something hard at that point, since there is a gouge in the aluminum - though it may also be the effect of an attempt to widen the slot.

If I do attempt to straighten it, I would only do so to apply load that would help to widen the slot. Probably the best first step will be to file the gouge smooth, then try to raise the sail. Has anyone seen similar?

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Re: Slightly bent mast

Postby GreenLake » Mon Aug 15, 2016 3:36 am

The only way you will really know is by raising the mast with the boat on the trailer and seeing whether you can raise/lower the sail. Speculation is useless.

Then, with the mast raised, take the main halyard down to the place the mast-slot hits the deck. Now you have a straight line to compare the mast to. How deep is the deflection (with the rig tight as if sailing).
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Re: Slightly bent mast

Postby Interim » Mon Aug 15, 2016 8:36 am

I have a bent mast too. My spot is a few feet above the deck (I have a deck stepped mast).

I don't have a problem with the slot, so my only concern was weakness or possibility of further bending. I was told that if the mast is less than 1" out of column, it would be fine. I have sailed it for three years like this, and the bend hasn't changed. Greenlake's method can help you measure the deflection.

I suspect a better sailor would see a difference in performance, particularly on different tacks, but I don't.

--john
1979 DSII
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Re: Slightly bent mast

Postby GreenLake » Mon Aug 15, 2016 3:34 pm

Boats are notoriously not symmetric. I bet, you'll always have a favored tack.

I very carefully removed a significant bend from my mast after the rigging failed. You can find a description in some older post (about a year ago). However, when I got the boat, it already had a very slight bend - visible only by sighting along the track. I left that alone.

A keel-stepped mast with a slight bend around deck level can be pulled vertical (or near vertical) by the shrouds, making the imbalance one of tension rather than geometry. For a deck stepped mast, this does not apply. However, go measure and check first before deciding that you actually have an issue.
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Re: Slightly bent mast

Postby jeadstx » Tue Aug 16, 2016 1:39 am

On the Texas 200 this year we had a boat (Cortez 16) arrive at the third camp with a noticeably bent mast. They removed the mast and took it ashore to evaluate and try to straighten it. The skipper of the boat got the mast mostly straightened by sitting on it while it was supported. My crew took the pictures so I don't know the exact procedure used, not sure if he carefully sat on it or there was gentle "bouncing" involved. Attached are a couple pictures, one showing the bend, the other showing the straightening. The boat sailed for another 3 days (about 110 miles) after this.

John

Bent Mast.jpg
Bent Mast
Bent Mast.jpg (250.6 KiB) Viewed 7032 times

Bent Mast Repair.jpg
Repairing mast on beach
Bent Mast Repair.jpg (215.93 KiB) Viewed 7032 times
1976 Day Sailer II, #8075 - Completed the 2011, 2012, and 2013 Texas 200
1952 Beetle Boat Swan Catboat
Early Rhodes 19
1973 Mariner 2+2, #2607 - Completed 2014, 2015 and 2016 Texas 200
1969 Day Sailer I, #3229
Fleet 135; Canyon Lake, Texas
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Re: Slightly bent mast

Postby KingsTransom » Wed Aug 17, 2016 11:42 pm

While fitting the new transom mast support, I had both the mast and boom on the boat and it became obvious how the mast was bent. The PO had an over-under trailering configuration, with the boom under and the mast over. The gouge, narrowing of the slot and bend of the mast are at the same point as the gooseneck of the boom. As received, there was a pair of wood blocks cut like a yoke to fit around the boom, and the mast sat on top of that. I would be willing to bet that at some point in its history, the mast sat on the boom directly. In my case, I think the solution is to have the boom sit on the deck off to one side of the mast, instead of directly below it. Closed-cell foam blocks will keep the boom off the deck and the mast off the boom.
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Re: Slightly bent mast

Postby jeadstx » Thu Aug 18, 2016 2:31 am

I used to carry my boom supported by the mast, but was concerned about potential bending. When I built my new mast support for the stern, I added a support for the boom forward of the mast support. Now my boom sits in the support at the stern and the forward end sits on the mast hinge plate and is secured there.

John

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2137
1976 Day Sailer II, #8075 - Completed the 2011, 2012, and 2013 Texas 200
1952 Beetle Boat Swan Catboat
Early Rhodes 19
1973 Mariner 2+2, #2607 - Completed 2014, 2015 and 2016 Texas 200
1969 Day Sailer I, #3229
Fleet 135; Canyon Lake, Texas
jeadstx
 
Posts: 1216
Joined: Tue Jul 08, 2008 11:10 am
Location: Dripping Springs, Tx


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