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Hollow mast project


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Guest Florin
Posted

mockup%20hollow%20mast.JPG

Yesterday I was playing with a bit of scrap spruce to see if I can make this hollow mast. Afterall it was harder to think about it than making it. The piece I made is just under 2' and is 3.5"x3.5" just like the real Vac spar. So I guess now that we are convinced that it actually works, we'll make the mast and the boom hollow by the bird's mouth method. The gaff we'll make solid for I hear it needs to be heavy. We'll have the stub mast solid as well.

I think I may start cutting the staves today. Is plastic resin glue good enough for gluing the staves?

Thanks

Florin


Posted

Florin,

The answer to your question is "it depends". It depends on how good a fit you get with the birdmouth. In my case there were some gaps between the birdmouth and the mating stave. So I needed thicken epoxy which can fill gaps in joints with no loss in the joint's strength. Plastic resin, and polyurethane glues, however, require tight fitting joints for max strength.

I'd use epoxy.

Posted
we'll make the mast and the boom hollow by the bird's mouth method. The gaff we'll make solid for I hear it needs to be heavy.

I think you've got the gaff and boom switched. It's nice to have a heavy boom and a light gaff. (At least I don't see any reason to have a heavy one). However, there's not much point for a small diameter spar to make it hollow. I wouldn't bother with a hollow gaff - it becomes to fragile. I had a birdsmouth boom that broke and I replaced it with a solid one.

Posted

Florin, Phil,

With my sailrite main I have trouble getting the gaff to fall when she is peaked up tight. My gaff is birdsmouth and I wish I had made it solid. I many times have to use the flag halyard as a dousing line. Keep the solid gaff, the diffrenece in weight on the Vac doesn't matter IMO.

Phil, will you carve one of those fine name plates for me? :)

v/r

Craig

Posted

Florin, you'll also want to be careful about how you attach things to the mast. A round hollow mast is very strong ... but like an egg. If you put an eyebolt through the mast from one side to the other, and tighten it, it will crack the mast. So you need to be able to either have the mast solid at that attachment point, or use iron bands around the mast to secure things to it.

For mine, I ended up putting a 1 x inside the mast stub, with some threaded inserts (t-nut style, but heavier duty) so that when I tightened the hardware holding the gooseneck on it "clamped" the 1x on the inside up against the staves. For the top of the mast, I used galvanized fence post hardware (for chain link fences) as cranse irons, which spread the stresses nicely around the circumfrence of the mast.

The gaff on the Weekender is small, but I made mine hollow anyway. Worked well, but was probably more trouble than it was worth!

Posted

Thanks guys!

I made the stub mast solid, and the gaff solid as well. For now I am going to make the boom solid too. Later on I will try making the hollow boom and add a traveller on top of the lazarette to keep the boom end down.

So the only hollow piece on the boat (possibly) will be the mast for now.

After I make my decision about the hinge of course.

Thanks

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