Mast snapped

[colorado ds]

Hoping for some advice re: a snapped mast...

The snap is clean and is ~8 feet above the deck (the mast section is 22 feet in total) and is located immediately above the side stay spreaders. I was wondering if I could use the following method (found in another post thanks to jdoorly) to insert a new section of mast into the two broken ends and then weld or rivet together. What length do you think the inserted sleeve should be compared to the overall length of the mast? And am I just plain crazy to attempt this repair due to the location of snap near spreaders? Is the force applied to a repair/pop rivets/weld too much to expect for my family to sail safely? Of course, I would get a local aluminum weld pro in on the job...

I have looked into replacement extrusion and rivets for a complete rebuild with my rigging etc. but my budget can't cope with shipping costs. I have scoured ebay, craigslist etc. for a salvaged spar, with no nearby success.

Thanks for any advice you have!

["But there is a standard method for lengthening a mast section. Mast makers, like Dwyer, can only get mast sections up to 25(?) ft long and must therefore scarf sections together to make long masts. What they do is take an extra section of the same mast profile about 10% of the total length of the mast, and cut away the slot area (after 20% of mast). The scarph section can now be folded in a little, but it's enough to slide half into one mast section and then the other half into the second mast section. Then put in a lot of equally spaced pop rivets in to hold it together and spread the load."]

[GreenLake]

OK. no personal experience, but I looked around and there's a discussion on fixing masts for 505s, which are not too different from DS in size. There, the suggestion is a minimum of one foot past the crack.

One difference is that in what they discussed there was apparently some welding of the crack in addition to the sleeve.

The location where your mast broke would have maximal side loads under normal operation (breaks below the spreaders should be loaded primarily on compression). However, I would still not randomly exceed the length of the sleeve since adding weight aloft is always detrimental.

How did it happen?

[colorado ds]

Thanks for your reply - a fallen backyard tree.

My husband is keen to try the repair, I am nervous that the join would be in a part of the mast that has to cope with heavy compression and lateral forces/loads. Perceived safety vs. saving $ is what it'll come down to, I suppose...

Thanks again.

[GreenLake]

Well, the fact that the damage isn't due to sailing is encouraging (it means that the mast wasn't loaded to its limits with a sailing load). By being above the spreaders, there are lower compression loads (main halyard only).

I would research this a bit more on the net, but in your situation I would be tempted to try such a repair (based on what I've read so far). if you look around, you might even find someone with first hand experience, like the one who posted on another forum about his repairs of booms and masts for a 505.

[jdoorly]

I agree that the location of the break near the spreaders could be a concern, although I think the small side load the spreader represents is more to prevent the mast from oscilating than to keep the mast in column.

Scott (hectoretc) did this repair and found it very strong; his fix was below the deck and probably takes more side load than a spreader, due to the mast step and partners!

I'd say give Dwyer a call and ask their advice, after all your are considering purchasing a length of DM284 section, 2 feet or 22 feet your still a customer...

I don't think welding is necessary unless there is a vertical crack(s), which should be repaired. It sounds like a clean break but I would expect to cut-away some of the mangled part, shortening the mast, so you have proper mast section shapes to join over the repair sleeve, or a longer sleeve and bit of mast section to replace what is cut-away.

[GreenLake]

Jdoorly, that sounds about right, except I would disagree with one detail. The spreaders on the DS are back swept, and that supplies a net forward force, which in fixed relation, ultimately, to the forestay tension (but I'm not going to try to estimate which fraction). I think that fraction is higher than what's needed to "just" dampen oscillations, because the purpose is to get the side stays to more efficiently pull backwards against the forestay tension.

However, I'm beginning to think that those repairs are probably quite strong, didn't you or Scott report an attempt to bend one? Major downside would be the weight aloft, but if not sailed competitively, it may not be worth the price of a whole mast.

About the welding, on second thought, that sounds like it would produce its own problems, as also discussed here: http://www.int505.org/old_site/fix-mast.htm

[DavidF]

I purchased a DSII last fall that had a similar injury and repair. Mine is less than 6 inches above the spreaders. I am not sure how the repair was done on the inside, but it was welded around the exterior.

The repair looks clean with no subsequent cracks. It appears to be quite strong, but I guess that I won't really know unless the mast snaps again...

I can take a pic and post it if that would be of use.

David.