1964 Columbia 26 mast support crack

[CraigL]

Hi everyone,

I recently got back into the water and had my mast stepped. We had a bit of a storm and tonight i noticed a crack in the mast step support under the deck. Rigging seemed to be too tight, ive loosened it a turn all round. Am I safe in just fiberglassing over the crack or is there more work that i need to do?

I've attached a picture of the crack.

[SofiaB]

The 5 holes under the crack; are those securing a compression post? If so I would think the stringers are only for lateral support of the compression post. If so I would simply secure the stringer to the wood with screws. I would also fix the crack.

[gulfstar37]

So give us a little more information. There appears to be a continuous hinge, piano hinge, on left side of photo. Is there a opening door under the support the crack is in? What's on the other side of the panel? More photos from all sides would help us.

[CraigL]

There is indeed a door to the hanging locker under the support. On the other side the stringer returns up to the deck. Don't mind my quick and dirty glassing in this photo, i needed some temporary strength.

[CraigL]

Aaand for some reason it has inverted that image...

[CraigL]

More angles...

[gmakhs]

The repair is done really bad ..... You need to grind it, probably is has wet core .

[CraigL]

Oh im aware that its a poor repair. This model doesnt have a core. Solid deck and hull. Which accounts for some flex and loss of strength.

[Don C L]

So I had the 24 and now I have the 29, and I have gone through this on the 29. OK so what we are looking at there is the arch that supports the mast is inside the liner. The wiring goes up inside the arch, directly into the mast, correct? There are no cracks apparent there. The arch is centered over the aft bulkhead that forms the aft wall of the head and hanging locker, correct? It would help to have some shots of the deck around the mast. Is there visible depression or cracking? If water has gotten into the arch (which is most likely exactly like mine, a laminated plywood arch) it probably has lost some strength over the 55 years and is allowing the mast to be pushed down. And you should see some evidence of that on deck around the base of the mast. Perhaps the liner is flexing and not showing cracking, but that stringer, for lack of a better word, going forward was not intended to carry that force but it ended up getting some, and it cracked. It could very well be time to do some surgery, as I did on my 29, to restore that mast support. More photos from above and below would be nice. Do you see any other cracking or deflection? NOW another possibility is that there is nothing wrong with the mast support and someone heavy stepped or jumped on that part of the deck when they were at the mast, cracking that stringer that runs forward (less likely.) I think I'd remove that patch and then see if it moves when you go sailing and/or walk on it; it needs to be replaced anyway. I'd be happy to let you know what worked and what I'd do differently next time with my surgery. I also have a lot of shots of what I did. But I do not have the liner you have and that may complicate things a bit. But it is a tough boat and the mast support was really the only weak point in my opinion and it takes 55 years for it to show up, so I'd say it's worthy of a week or so of repairs
For those not familiar with the boat I added a drawing:

[Don C L]

As an FYI here are a couple shots of the laminated plywood arch in my boat and what is on the inside. I had a good deal of deflection and the PO had tried something with straps that didn't really work. I cut out the water damaged section there and it helps let you know what is in there.

[CraigL]

Don thats awesome, thank you! Any tips you could provide would be greatly appreciated. Here are a few more pictures, there are no cracks on deck but there certainly is some deflection downwards in the deck. The two wires protrude beside the mast and would almost certainly be the cause of any water intrusion... I take it this is a mast down kind of surgery?

[CraigL]

Don, did you notice flexing while under sail that pointed the issue out to you? How much deflection under sail should i be concerned about? I was out in moderate wind last weekend using just the main, if that caused the crack then im slightly worried by the prospect of going with the genoa as well...

[Don C L]

Judging from the photos I am not yet convinced I am seeing a compromised support arch in there. But, yes, those wires would be a likely source. If they were sealed up well when installed they could be fine. Another source is the two bolts that hold the shoe (the part that the mast rests on and sleeves inside the mast) to the deck. Be aware that if it is clear the support is damaged and you have to repair it, the mast will likely be welded to that shoe from 55 years of corrosion. Mine was. When the crane tried to lift the mast off for me the guy said, "wow, we're lifting the whole boat!" We had to rock the mast back and forth to break the bolts free of the shoe. In my own case the damage was much more obvious and the previous remedy, which was insufficient, was right there to see. And I could see the depression in the deck from above and below. Yours is not so clear to me. I'll make a new album in my profile of photos of what mine looked like and how I dealt with it that you can check out, but as I say I am not sure yet you have the problem. I BELIEVE the part that is cracked is structural only in terms of supporting a person standing on the deck there. I still wonder if it could have been caused by something else. In any case if you sail it, or perhaps even try to pull it over at the dock with a halyard down to a neighboring slip, you may see it flex. I will say, though I thought my 24 was going to suffer a similar fate, it never did and the arch never moved or flexed. Even damaged mine was surprisingly strong on my 29. If you have someone sail it for you, or you tie off the tiller for a while, on a fairly breezy day, you can open the head door and use something to measure up to the base of the center of the arch and watch to see if there is any movement. Like I say though, based on the photos, I suspect it is ok. I am trying to figure out how the force was translated all the way over to that crack though, it's a puzzle. More photos is always good And BTW, the other side, above the head door shows no cracking or deflection at all right?

[Don C L]

OK, looking again, the arch DOES appear to have a downward trend or flattening, to the right, that is starboard side, of the mast step, from the inside, the same side as the part with the crack. Is that what you were referring to also? If so, and the wood is compromised on that side from water intrusion, that could be what is going on.

I posted a new album with photos and here is a thread about the engineering in it... which I send along somewhat shame-faced because I really should have consulted engineers before doing the work. Still, it turned out ok, but I'd not do it that way next time. Thanks again to Eigenvector for the invaluable help with that!
http://www.cruisersforum.com/forums/...se-186039.html

[CraigL]

There is a very minor crack on the head side much farther forward which would support the deck impact theory, combined with the fact that 4 burly gentlemen were standing there to do the work. As a temporary measure i am going to scribe a piece of oak to fit as a support for the season. The mast lifts easily, was on a cradle for winter up here. Come to think about it it was very rolly the day it was stepped, i wonder if the boat rose under it and took the hit. It would make sense, that was just before i noticed the crack.