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Building Birdsmouth Mast
by Bob La Quey

Building this mast is part of a larger project, a small trimaran, modeled vaguely after a Filipino Banka which I am building.

(click images to enlarge)

click to enlargeI found some clear 3/4 inch by 8 foot long white pine at the Home Depot and so decided to try my luck at making a birdsmouth mast. I found a couple of good web sites, one by Frank Hagan and another by a fellow known only as Bill. Then I simply dived in and started making saw dust. First I needed to rip a bunch of sticks ... since I have cheap saw I have found it helps to make a simple jig for almost everything. Here is the jig for ripping.
The next task is to scarf the sticks together. They were only 8 feet long and I needed 13 feet so ... I built a scarfing jig.
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click to enlarge
And then started cranking out scarfs (not perfect but good enough) ... Then the fun began because it started to rain. Now the fact is I work outside because I like being outside and this is Southern California. We went 180 days this year without rain, ah heaven, but now it is getting cold and rainy. So for the rest of this project I am struggliing with trying to get something done by sneaking through on the rain free days. We will get a few days clear and then it rains.
So here we see a simple scarf being glued. The clamps are from a 2 inch piece of abs pipe. Works great! and very cheap. The feet are from yours truly.
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click to enlarge
Now that I have a bunch of 3/4 inch by 1 3/8 inch by 16 feet long sticks I am ready to make two 45 degree cuts with my table saw so as to create the "birdsmouth". As usual I need a jig. I ran a few test peices through until I was satified and then went into production.
Here are the results of carving the birdsmouth in the sticks. Next I cut all of the sticks off to 13 feet long. I staggered the cuts so as to spread the scrfs around as much as possible.
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Then I decided to add a taper to the top 4 feet. But it was starting to rain and I was hurrying. So I just free handed it. Well they say "Haste makes waste." The results were really lousy. I wound up with a bunch of sticks that look pretty good for 8 feet then have wandering tapers for the next 5 feet. I am not a craftsman. Never really aspired to being one since I like to build something once then move on. To become a craftsman you need to do most things more than once. I may just add some carbon to this part of the mast if it is too bad. We shall see.

I am now working on "I wonder how lousy a job I can do and still get it to work?"

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I decided to test for fit before gluing. Here you can see the results. Note the nonuniform taper. If I were devious I suppose I would feature this, chuckle, as special tuning of the mast.
Here are the results of carving the birdsmouth in the sticks. Note how the top few feet look. The taper is mostly from 8 feet up to 10 feet after which it is fairly uniform in radius untill the top i.e until 13 feet. It actually does not look too bad. So I will see what it looks like once I glue it up and fair it.
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click to enlarge

Glued up and initial fairing done it actually is turning out reasonably well.

That was really kind of fun. I think I will do it again sometime. I have found some decent clear straight grain fir at the local Home Depot and so would like to make a mast of this fir. This first mast is a bit heavy and so I will likely tinker with the scantlings some for the next one.

Bob La Quey