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The WBAC brains trust met and looked over the existing mast, boom and mainsail and decided that BT needed a new mast, (the existing one being both very heavy and with some rot in the centre). The boom and gaff are both to be bamboo as there is some uncertainty over the use of the existing mainsail, but the mast needed to be properly built.
Phill Smith’s success in constructing the mast for Iona in his backyard, gave us confidence that a “birdmouth” mast would be both strong enough and light enough for the job.
Sourcing suitable high-quality timber proved an issue.  We made multiple phone calls and visited timber yards to no avail.  Hoop pine in the required dimensions is almost impossible to get and Oregon from Victoria was very expensive.  Luckily one of the members came to the party and from his private store we acquired two lengths of Sassafras.
The standard “birdmouth” mast is made from 8 lengths of timber, (it can be more but the angles get more complicated), so the timber was cut down to 34mm x 25mm, 5.5 metres long to give a mast of about 90mm diameter.
The calculation is on this webpage:
https://www.duckworksmagazine.com/10/howto/birdsmouth/index.htm
Because of some minor termite damage, we actually cut 10 lengths, but discarded 2.
The cut-out on one side was made with a bench saw set at a 45° angle and some trial and error to get the height right. 2 sets of plastic fingers were used to keep the timber against the guide and a block set above the blade to keep the timber down to the bench.  One pass each way and the cut-out was done. Only had to do it 16 times!
With hindsight the cuts could have been a little deeper to make sure that there was no residual timber at the base of the cut.  We had to run the timbers through the saw a second time to remove this residue, so the joints were tight.
To glue them together, we made 5 cradles/saddles with a ½ moon cut out at the expected diameter of the unfinished mast. These were clamped to a straight length of heavy timber and checked for straightness and bowing.  About 8 hose clips and lots of cable ties were prepared to hold it all together and a team of 6 assembled.
Two people were instructed to hold the end of the mast in position, 2 to apply the polyurethane glue and 2 to spread the glue along the timber.  All went well, until it became apparent that we did not have quite enough glue.  About 50cm short!  Panic!!  While one person made a quick trip for some more, by dint of scrimping and scraping, with the glue going off, we got enough to finish, and the mast was hose-clamped and cable tied together.  A quick check for straightness and it was cake and coffee time.!
Taking off the clamps a few days later showed that the mast had set well, was straight and not too heavy.  Very relieved.
It was power-planed back to 8 sides, and then hand planed to 16 sides before the serious work of sanding started to get it round and a standard diameter. This one will probably end up about 85 mmm.
We learnt that it takes more glue than expected, that polyurethane glue goes off in the tube so there is not as much as you think and that you need more time to glue and clamp than anticipated even with 6 people.
 
Roger Fryer 15 May 2024