Being time rich and money poor it's going to have to be timber as my only costs will be material and those will be around $100. That's for the Yard and the Boom. At least they will match my clear finished mast.

The yards on Easy Go are 3 inch by 1/4 inch tubing. The battens are 1 inch by 1/8 inch tubing. Sorry I can't convert these to metric. They have many thousands of miles on them and are doing a great job so far. The yards have rope loops to the halyards that have worked flawlessly. No need for fancy fabrication.

Okay, slight reality check The nearest T6 I can get is 63.5 x 6.35 which is a fairly thick wall and is $23.18 + GST per metre. That comes to $131. The tension tube will cost me around $21, then there is the Boom and the welding.
So I'm having another look at timber. I can get enough recycled 150mm x 37mm Oregon to laminate a Yard and a Boom for around $80. And I have enough epoxy to glue it up. A mate has offered to thickness the timber for me so I think I will go with it.

Gary

Gary,

You should try and get aluminium in grade 6063 T6 for the main tube (T5 (more common) is OK for the tension tube as it just in tension, does not have to deal with bending but T6 will not hurt if you can get it). In NZ T6 is generally very hard to get (unless you specially order it, minimum order 120kgs) So I used blank dinghy masts which are readily available from the local rigger in the correct grade. If you cannot source T6  and have to use T5, you should go up at least one size in diameter.

Two changes you should make:

a) Make the riser (plate between the main tube and tension tube) about 50mm taller. You want the angle between the main tube and the tension tube to be 8deg or greater

b) Extend the tension tube to within about 100mm of the ends. This will put the tension tube under load earlier and should make things stiffer.

Lastly when you tack the tension tube to the main tube before starting the full welding, put some pre-bend in the main tube (the bend should be away from the tension tube) this is because when you weld up the two, the main tube tends bend upwards due to weld shrinkage.

PS. You could make the ends simpler by just making plastic or even wooden bungs to close the ends. Then you can just dill holes for your lashings, also avoids arguments with the anodiser who will want to drill holes in you nicely sealed ends.

PPS:I'd normally make the yard about a 200mm longer than the sail to allow for stretch and unknowns.

PPPS. For Annie's boom batten, I used a 50mm dinghy mast.

Paul I've downloaded the drawings and printed them out, I have say I'm very impressed. I think I will just go with the same dimensions apart from making it a bit longer for my sail. One question, how much outhaul did you allow for the throat and the peak? I don't know the dimensions of Annie's sail.
Cheers, Gary