hollow box mast

[Bill Paxton]

There are plans for making a lightweight, nearly hollow, box mast on Dave Grey's PolySail website.

http://hometown.aol.com/polytarp/mast.htm

Has anyone built one of these? I'd be curious to know if such a mast would work on a Weekender. Any thoughts?

Bill

[Charlie Jones]

two things I can think of right away.

First, a gaffer doesn't do well with a box style mast- the gaff jaws really sorta need a round mast to rotate on.

Second- a round, tapered Birdsmouth spar can be built very quickly and can be made quite light by varying the size (thickness ) of the staves. A birds mouth spar is hollow also.

If it were me, I'd go with the birdsmouth if I wasn't going to use a solid mast per plans. That's exactly how I built the Weekender I built.

Having said that, there's not a thing wrong with the idea, just I really think , not for a Weekender. In fact, I talked a bit with Graham Burns about using plywood for the sides to build a box boom for my Rhodes Meridian 25.

[Simon]

I recently constructed a pair of tapered bongo drums using the birdsmouth method, one 8 stave and one 10 stave. It gave me quite a bit of insight into birdsmouth contruction ... I don't think I'll bother for my mast, it hardly seems woth it really, I'm thinking the extra length could compound some of the problems I had with the drums .... I really like the drums, though I don't think I would have started if I'd known how hard it would be.

[Charlie Jones]

What kinds of problems did you have? Really curious to know.

I remember building the bowsprit for the Weekender. I kept track of time for that particularly for a post on it. Took me three hours working time from the time I stepped to the radial arm saw to cut the staves to length, to the time I had a sanded round spar, ready for varnish. This does not count glue curing time of course, just my actual working time.

Of course, that spar was straight, not tapered. Tapering does add something to the time to prepare the staves, but after that everything is the same. I cut and tapered the top part of the mast in about a day and a half if I remember correctly.

[Simon]

Well, to be honest it wasn't just the method that I had problems with, more like making rash decisions. For a start I decided that I would just "whip up a drum this afternoon" and it was a 6-stave. I did the calculations for the angles etc. but didn't really think about what the finished size would be ... after I'd made all six staves and masking taped it together I came to the realisation that it was much smaller than I''d envisioned, and indeed pretty much useless.

So then I decided to make an 8-stave - same sized staves, same taper, different angles on the "birdmouth" part. I got the whole thing taped together, nodded sagely and then went to a supplier and ordered lugs and fittings for a drum that was 2 inches larger than the one I had just made ...

Then I though sh*te I better make a 10-stave drum, to use these fittings that I just brought, so I did the calcs, cut the tapers and half way through routing the birdmouth my router started screaching and not cutting ---- the collet was no longer gripping the router bit --- the bit was obviously kaput, its shaft was all torn up. The collet looked slightly glazed inside, so I played it safe and brought a new bit and a new collet. Finally back at work on the drum I cut the birdmouths ... 10 glorious hard-earned staves which .... did not fit together ... bugger. I had accidently cut the complementary angle in the birdmouth ... I was 90 degrees out, which meant that I could just about fit my ten staves into a hexagon which left me with 4 remaing staves, a bunch of useless (and expensive) drum fittings and a tension headache.

Long story short I eventually sorted out the problem and managed to cut ten new staves which worked .... it was just that acting on a whim on a Sunday afternoon had created a whole mess of problems that I really hadn't anticipated. I cut 34 staves to make 18 that I could use.

[Charlie Jones]

LOL- I've had days like that