Thread: Building Shesha, a Hunter Valley GIS, Australia

My Goat is under cover so I can't measure it but the frame piece across the top of the transom should come down to the tiller cut-out, or very close to it. Use the cut-out location to determine which width is correct.

It is not critical (but I have put a note to myself to fix it up).

The main thing is you don't want the underside of the top stiffener finishing ABOVE the underside of the inwales. So that sets the top limit.

The bottom limit is that it should not interfere with the tiller hole, so that sets the bottom limit.

MIK

Originally Posted by Boatmik

It is not critical (but I have put a note to myself to fix it up).

The main thing is you don't want the underside of the top stiffener finishing ABOVE the underside of the inwales. So that sets the top limit.

The bottom limit is that it should not interfere with the tiller hole, so that sets the bottom limit.

MIK

Okies Mick, that's good to know, so thanks.

On another matter, my hoop pine mast staves (for box mast) have finished at 11mm thickness and 12mm is specified. I'm thinking that 1mm won't be critical at all as I've read elsewhere on the forum that nobody has yet broken a GIS mast so the design is clearly pretty solid?

Also, how critical is it to have the 3 layers of glass for the bottom section of the mast as mentioned in the instructions. Would one layer suffice?

Howdy,

The 11mm will be fine. you will have to increase the width of the narrow staves by 2mm to make sure the mast is still square - but no structural problem.

I think the glass is not very necessary - the masts seem to have very little problem. So suggest that you just need a couple of layers of glass tape at the base and at the partner to reduce the risk of crushing against the partner and the risk of the butt splitting.

MIK

Hi, I made my mast yesterday, or 90% of it anyway, from Hoop pine and Paulownia. Hoop for the staves and Paulownia for the infills and blocking.

I have only to coat the inside of the mast (or is this not necessary?) before glueing on the second wide stave.

Also, just wondering about determining what is to be the front of my mast. The plan instructions say there is no structural preference. I presume therefore that the orientation of the angle cut for the infill at the base has no real relevance?
I broke two of these clamps due to some overzealous tightening. The ratchet lever pins just disintegrated, and they wern't exactly cheap either. Later on when I was glueing on the wide stave, two spring clamps went flying as the nylon handles snapped under the load of the springs. They were open to their fullest extent, so were right on the limit. They were pretty cheap Bunnings ones - about $1.70 each I think.

That's my helper Lizzie checking my work...

Looks excellent. There is no preference at all for the orientation of the mast.

MIK

I've just planed down the wide staves on the box mast and in its very rough state it weighs 7.8kg, which I think is quite light. It will be interesting to see how much the fittings and finish will add to the weight.

I am very pleased that it has ended up nice and straight

Originally Posted by woodeneye

I am very pleased that it has ended up nice and straight

And pretty, too! It looks great.

Bob

Originally Posted by woodeneye

I am very pleased that it has ended up nice and straight

OMG, he's made the world's longest cigar box

Richard

Hehe, yes, and the Hoop smells a bit like cigars to me.

I routed all the spar corners with a 9mm roundover bit this morning. It's the first time I've ever used a router. I was a bit daunted at first because it's a big 5kg Maktec (made by Makita) machine that I bought on FleaBay. However, I found that a big, heavy machine with power is quite easy to use as it tends to stabilise itself.

I did a couple of practice runs on some scrap and then ripped into it. Piece of cake, it's a lovely machine and it ate up the Hoop, leaving a great finish. I found the adjustments to be quite user friendly and easy to make

Now I just have to sand and apply the finish.

The mast ended up 7.4kg. The boom and yard are 2.0kg apiece. The shorter one is the boom.

I've also attached a pic of the foils. The colour in these pics looks very red, but in fact its a port wine colour.

Time for a coffee!

Looking really good Bruce! The mast,yard and boom weights are excellent. Are you leaving the yard and boom rectangular in cross section? I like the way that looks and I'm guessing they should bear well against the mast since the pressure is distributed over a larger area than on a round yard and boom. You are inspiring me to get back at working on mine.

I think rounded off corners for the boom make some sense. I think a stiffer boom is a good thing - from the Dutch feedback.

But the yard is better off round.

MIK

The reason I have left both boom and yard edges rounded for now is because the timbers are not very fine grained and they seem very flexible to me. My thoughts are that these will be a spare set and that I will laminate some timbers to make another set. I can always trim them down if needed to suite my sail.

Mick, do you have any flex measurements for the boom and yard as a guide? I'm worried that the spars I've made will have too much flex, but as I have no experience with the lug sail, I am hesitant to take off any more timber at present.

Fine to sit on it for the moment. They are tapered though?

I don't have figures off the boat. You might be right too. The spar weights you have are quite light indicating the timber is low density. There won't be a hint of concern with the mast, but you might be right about delaying the full shaping of the yard.

Michael

Best wishes
Michael