Thread: GIS Yawl

Originally Posted by Boatmik

However (don't I love those sentence conjunctions!!!!) why not make it OZ light and put in bigger water tanks for ballast?

MIK

Mik,

I wondered the same exact thing...I think there isn't enough room in the boat. Already the volume under the false floor is used for the water and at least one user, maybe more, are complaining that the false floor is too high in the boat...they were trying to get about 4 adults worth of volume in the bottom of the boat for water ballast. They did a great job, I think, with a very tricky design challenge.

What I like about the yawl rig for the Goat is that when sailing solo that mizzen will be very handy for beach cruising, sailing with a green crew, and doing sail-and-oar type things, like the Maine Island Trail here in my backyard. And the best thing is that often the mizzen will just stay ashore and the standard Goat is still there!

I noticed the boomkin-sprit mizzen arrangement in the skiff yawl posted a couple back...one of my uncertainties is the sheeting angle that is right for such a sail. If you look at the way I drew it (much like I've seen on Oughtred boats) the sheet pull forward on the end of the sprit. Others I've seen the sheet pulling more down and aft. Which is better?

Cheers,
Clint

Post #34 shows the yawl rig. I have stretched the mizzen vertically a little more. It is now 9' long and looks nicer. The mizzen is 15 Sf lashed to the mizzen mast. I will go with this rig. There are still questions:

1) How long should the boomkin be/what sheeting angle would be best for use with this sprit mizzen.
2) If I cannot find a carbon mast I may go with a spruce birdsmouth and make it as light as possible. This brings up Birdsmouth questions, more on that later.
3) Since I will be doing some trips with the boat and carrying gear I wondered about raising the tops of the tanks for added buoyancy. Would be easy enough to do, unless I am not thinking of a complication. But what will the current tanks float for weight?

Birdsmouth. Maybe it's own thread!?

Cheers,
Clint

Howdy Clint, the tops of the tanks are already out of the water after capsize.

The best way if you want a heck more volume is to box in the centre seat. I even occasionally think of extending it forward a bit too. You would need to organise limber tubes through the mid seat area.

As far as the birdsmouth mizzen ... I think it is hardly worth it ... the stick will only be about 45mm diameter and rounded. But you like these tricky jobs! If you wanna ... I am right behind you!

Spritsails are a bit independent of sheeting angle because the vanging is taken care of by the snotter tension.

I generally have two setups I use for boomkins to prevent the sheets from snagging round the underside.
1/ Have the boomkin a bit shorter than the length required for a vertical sheet This way if a bight drops in under the boomkin it will probaby pull out from under with a tweak on the sheet.
2/ Have the sheet leading slightly forward as it goes up to the boom, and have the boomkin a good 100 mm longer than the sheet position required .. the excess length on the boomkin helps prevent the sheet from dropping under the boomkin in the first place.

MIK

Michael, that 45 mm figure is that constant or can we taper that towards the top a little. 45 mm to 35 mm? That would make a straight taper and cutting staves for a B'mouth easy. I'm still looking for a composite windsurfer spar.

Howdy Clint,

There is nothing nicer in this world than a properly laid out taper. The classic taper also means you have the right stiffness at the right height for the load. Or pretty close.

Do you want me to draft it up for you? Or do you know the method of drafting up a circle twice the diameter of the mast and dividing it up?

MIK

I don't know that method, Michael. But I have learned through this process so lets keep going!

I am in the process of finding wood for the boat! It will be mucho Eastern White Spruce for spars, side frames, gunwales, and knees/breasthook and probably Cypress for chine logs (trying to find reclaimed wood) as well as for bottom frames and maybe side frames if the Spruce is so-so. Throw in a little native W. oak for skids, and ash or walnut or cherry (something tasty) for g' wale capping. This is a favorite part of project planning; like going to the ice cream store. I am killing 2 birds and doing the same wood assignments for the MSD that our students will start in a little over a month. If I get lucky and find clear enough Northern White Cedar I'll use that in place of the Cypress.

Why I can't find a carbon stick for the mizzen, I do not know. But I have enough leftover staves from another B'mouth spar that I think that will be a good use for those leftovers.

I always start thinking about a name for at this stage, very important! I do know that it will be a teal color hull with white underbody/varnished interior of course.

Stay tuned; I have to redo the woodwork in a canoe and make some spars for another Goat first.

Cheers,
Clint

So it will be a larger version of the Slovenian GIS model by Koala!

I thought that model looked fantastic ... so a full size one will work too.

Best wishes
MIK

I can't decide. The first yawl is pretty jolly.

Maybe the second will be better.

So, this mizzen rake is good. It is about 15 SF. 9' tall mast. It's a keeper.

The first image, the jolly one, uses a sprit. New trend?

Cheers,
Clint

Hey Clint,

You had me going there!!!! I looked at the thumbnail and thought "what the hell is he doing .. it was all sorted out .. and now he is changing it"

Haha! Well done.

MIK

Gotcha. Merry Christmas!

I forgot to ask in the above...

Any need for a short light batten or two in the long leech of this mizzen?

Battens make the furling of the sail agains the mast impossible.

But also .. if the sailmaker cuts it correctly I don't imagine any problem at all. Haven't seen any actual problems over many, many sails on a great variety of boats ... so it seems sailmakers get it pretty right.

Best wishes
Michael

Mik, TX, that makes sense.

What would be the best place to ask about conflicting info in the manuals?

--Clint