Association Forum - Slight Bend in Mast

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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Slight Bend in Mast

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jon300c
Deckhand

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USA
19 Posts

Initially Posted - 05/08/2018 : 09:31:51

Hi everyone,

I obtained a "free" 1978 C-25 swing keel a few weeks ago and after getting her settled I went to remove the mast from atop the boat and noticed that about 6 ft up from base of mast there is about a 5 degree bend going from fwd to aft. Do you think this is something I should correct or would it be ok to sail the way it is.

https://photos.app.goo.gl/r9itNpW5JvLP8kkf9

Thank you,

Jon Savage
Jacomo Sailing Club - Kansas City, MO

Edited by - jon300c on 05/08/2018 09:36:57

odonnellryanc
Navigator

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108 Posts

Response Posted - 05/08/2018 : 11:35:35

Just curious (as I'm not qualified to answer), do you notice any damage around that area? Kinks or anything like that?

Also, lots of things you need to check out with a new swing keel. Look around here on the for tips to make sure you know the ins and outs of these boats! :)

Steve Milby
Past Commodore

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USA
5851 Posts

Response Posted - 05/08/2018 : 12:36:48

It's hard to tell from a photo, but as a general principle, the strength of a mast lies in it being straight - "in column." It loses some of it's strength if it's bent.

But, having said that, I have heard of people straightening their masts, and here's a link to a video showing one way to do it. https://youtu.be/JIJaUKt_k20 Notice that he is very careful, doing it a little and then eyeballing it to see how much more is needed.

Here's how another person described his method: "Position the bent area over a fulcrum point that is long enough that it won't cause a kink, and will hold one end of the mast 2 or 3 feet off the ground. If the bend is nearer one side; park a vehicle over the short end of the mast, and pad the point of contact. Bend the mast past straight, so it will take a new set as it springs back. I straightened a fairly heavy wall 33' mast by myself in that way."

If it's kinked, then I believe the correct way to straighten it is to cut it at the kink and then sleeve it, but hopefully it isn't that bad.

I'd suggest you try to straighten it, carefully, so you don't do more harm than good. If you aren't able to straighten it, frankly, I'd put it up, snug down all the rigging to hold it firmly, and then sail it, but don't let it become grossly overpowered by too much sail area in too much wind. I've seen quite a few masts on boats that are sailing around with more bend than that, either intentionally or otherwise.

Steve Milby J/24 "Captiva Wind"
previously C&C 35, Cal 25, C25 TR/FK, C22
Past Commodore

GaryB
Master Marine Consultant

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USA
4275 Posts

Response Posted - 05/08/2018 : 17:07:44

If you end up needing to replace the mast hewebb had a Standard Rig mast for sale last year. He was asking $200 at the time. Not sure if he still has it's but worth an email.

He's in the DFW area so not tooo far away. Look in the Swap Meet section of this forum.

Probably be a lot easier than trying to straighten your mast.

Association Member

GaryB
Andiamo
'89 SR/WK #5862
Kemah,TX

Edited by - GaryB on 05/08/2018 17:11:50

Lee Panza
Captain

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USA
465 Posts

Response Posted - 05/09/2018 : 07:52:10

Jon:

I would not worry much about that small amount of mast bend.

That much bend is not likely to be a serious factor in the strength of this spar. The vertical loading in our little Cat25's is not that great, and the amount of bend shown in your photo is relatively minor. Photos can be a little deceiving sometimes, but it appears that the bottom end is still pretty much within the imaginary "footprint" of the upper portion of the mast, meaning that the compressive load is still within the structural section of the spar. With the kind of loads this column carries, the horizontal component induced by this degree of bend is still not major and should not even begin to approach the magnitude needed to cause a buckling failure. It's not uncommon to deliberately induce more bend than that in order to flatten an old mainsail (although, admittedly, that bending would be focused at the mid-height where the lower shrouds serve to stabilize the column).

I hope I'm not reading this wrong, but it appears from the photo that the bend is concave forward: I'm presuming the object visible on the right edge of the mast just above that styrofoam block is the steaming light. If this is the case, the horizontal load that will be imposed by the boom will tend to straighten the mast. Think of the mast and boom as a truss standing on end, with the boom serving as the kingpost. The tension between the sail (pulling the aft end of the boom upward) and the mainsheet and vang (pulling it downward) induces a powerful lateral force directed forward at the gooseneck fitting (when the boom is amidships while you're working upwind in a fresh breeze). The pre-bend you have in your mast will resist that forward force.

Just to put this in perspective, the amount of lateral force induced by the mast being this much out-of-column should be far less than the amount of lateral force induced by the boom. The structural section of this spar has much more bend-resisting strength fore-and-aft than side-to-side because of its oval shape. You will observe this by supporting it at its ends and rotating it: it will sag more when it sits sideways-up than when the forward edge is facing up or down. In normal use, when the boom is hard over it is imposing a significant lateral load on the mast in its weaker direction. But, as we know, the mast does not bend appreciably from the boom load.

I would not encourage trying to straighten this mast. You could easily do more harm than good. Just go sailing and don't lose sleep over it.

So, Larry, is this optimistic enough? ;-)

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

Edited by - Lee Panza on 05/09/2018 08:25:35

jon300c
Deckhand

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USA
19 Posts

Response Posted - 05/09/2018 : 13:06:01

Hi all,

I appreciate all the input. I will hold off on trying to straighten at this point. I sail on a small 970 acre lake on the east side of Kansas City and more than likely not sail in anything over 20 to 25 mph. If I notice it getting worse then I will attempt and if I make it worse I can buy a straight used one. I have a lot of work to do on this boat before I can launch her. The bow pulpit was hit and caused a hole in the deck and has been in open for year+. I get to have some fun replacing core and all that entails. I will start a new thread this next week and show my progress over time until I get it completed.

Jon

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