Mast Repair Advice

[bigd14]

I've been thinking about this on and off over the past year, and now is the time to really figure it out. The mast is in reasonably good shape except for the area around the spreaders. There are a bunch of excess holes, and the old spreaders have compressed the mast a bit (a dimple) on both sides. Also, the entire area around the spreaders is slightly compressed a little bit (1/32-1/16" maybe) over the space of about a foot or so. Looks like the spreaders were subject to some violent force at one time. Anyway, the whole area looks a bit weak.

Here is a shot of the area, with some notes on the different features.


Here is the mast profile. The aft wall between the main compartment and the sail track is near the dimpled portion of the mast.

So I have been thinking about putting two big reinforcing patches over each side of the entire affected area and then redrilling only the necessary holes. I have heard that it might be wise to make this in an elongated triangular fashion (tapered up and down the mast) so as not to create a hard point right above or below the patch. Also, this guy here http://home.comcast.net/~ericson-yachts ... epair.html repaired it using a big exterior sleeve, but had some trouble, so I am not sure that is the way to go.

Any advice?

Thanks!

Doug

[Mario G]

I would think you would want to make the patches small as possible so not to change the flex of the mast is a good idea. what about an internal sleave also so the hmast can not be de-pressed. On yours you might beable to straighten the dimples by useing a rod and hammering from the oppisite side. a wood block backing and lite taps then an over patch would work. If you see spider cracks in the aluminum , thats from fatigue.

I just had problems with my spreaders and not sure if fatigue after 33 yrs I need to think of ways to keep things in good order or go new.

[okawbow]

I'm certainly not a rigging expert, but I have been working on 2 aluminum masts for my Cheoy Lee ketch. My masts have aluminum tubes welded through the mast where the shrouds attach. These tubes keep the mast from collapsing in where the bolts for the rigging go through the mast.

It seems to me, that a tube passed through the existing hole at the spreader point, and welded to both sides, would provide resistance against spreader compression. You could also use the tube to expand your mast back to it's original width during installation, if you welded one side first, and then pressed the unwelded end of the tube into the mast until the width was back to normal. Then, weld the tube in place, and release the clamp.

Would the tube inside the mast cause a problem somewhere else? I don't know, but my masts have them, and have worked for a long time.

[Triton106]

Doug,

My Triton's mast had much worse weak spots around the spreader bases. I did not have any confidence, skill, or time to make the repair myself so I had our local yard Svendsen rigging shop work on it. The patch they made to the mast is similar to what you described as elongated triangular shaped patches, although I think an elongated diamond shape is a better description. I don't have the data on the gauge of plates they used for repair but could call them to get that if you would like. I also asked them about putting an all around sleeve they did not think that is necessary or a better solution. My guess is that in order to make a perfect sleeve to fit the existing mast they cannot use too thick of a plate where as the plates they used on my mast repair is pretty heavy. In any case I have been sailing with the repair for over three years now on the bay in wind speed over 30 knots and have not had any problems with it.

Good luck with your repair.

[bigd14]

Thanks for the replies. Chuck I did have a compression tube on each through bolt to prevent the mast walls from collapsing, but it may have been a little short. I will definitely be using compression tubes again. However, I understand that welding the aluminum can weaken it a bit, and I don't want to do any more damage!

Ray, do you happen to have some photos of your repaired mast?

I will be talking to a local rigger soon, but I'm trying to figure out all the options before hand.

Thanks!

Doug

[Quetzalsailor]

One does have to have a competent welder for such an important repair. I had cracks welded up in a mid-60s Proctor Flying Dutchman mast; it was serviceable. The whole 26' mast weighed about 19 lbs so the wall thicknesses are quite thin!

I've stick-welded aluminum architectural alloy door components successfully with my reverse polarity DC welder. Wall thickness was about 1/8". The technique was good enough for that application. The anodizing will craze with the expansion.

If I were repairing the mast in your pics, I'd stuff it back together with ferrules of the correct length and (very slightly) oversized bolts/sleeves if there was appreciable slop in the existing holes. I'd bed the spreader fittings while assembling. I would not drill more holes.

If the mast is slightly cracked at the holes, I might be tempted to add doublers, fastened with tapped flathead machine screws. Fasteners would be at some ample distance from the existing holes. (Quetzal's mast is internally doubled at the foot with such a system.) Doublers would be long and tapered, like the tangs on classic wood masts (article in WB or PBB recently).

[Triton106]

Sorry Doug I did not have a picture of my mast repair work. So yesterday while I was at the boat I took a picture with my Black Berry (I did not have a camera with me) the best I could. Here is the fussy picture. I will remember to bring a camera this weekend and get a better shot. Good luck.

[bigd14]

Thanks for the photo, Ray. I imagined that your repair plate would encompass more of the mast. Interesting. Quetzal I like the idea of doublers, but I agree more holes in the mast is not desirable.

I'll be talking to the boatyard down the way this weekend to get their ideas.

Doug

[bigd14]

I had a reputable local yard look reveiw my mast and tell me that I should be looking for a new one. Ouch. This is something I will consider at least until I get sticker shock. Anyone in the Pacific Northwest have a favorite local or semi-local spar shop?
Thanks!

Doug

[Pinching]

Have you considered tube replacement if the MH and other bits are removable?

might check Rigrite.com

[bigd14]

Guess I forgot to update this post. I spoke with the folks at Ballenger Spars about the problem, sent them some photos, and they figured out a fix, involving some new mast repair plates, spreaders and a spreader bar. Here is a photo of them. This will require quite a bit of fiddling to install. Sometime this winter I will tackle the mast. In addition to the repair and spreaders, I basically need to strip it all down and replace all the corroded coarse (!) threaded screws and bits of hardware.

[Triton106]

Doug,

Thanks for the update on your mast project. Ballenger is an excellent resource for spar problems. My Triton had a similar setup before, the only problem is that who ever put it together used steel for the spreader bar and did not isolate it from the mast. As a result, over the years the corrosion from dissimilar metal ate a large hole through the mast, ergo the need to patch it. So the only thing I would suggest is to ensure that the spreader bar is aluminum also.

Good luck.

Ray

[bigd14]

Yep, its all aluminum!