Thread: Is that a 12' GIS I see hull down on your horizon

The Dabchicks rigging is of course a bit more complex than for my GIS which offers sophisticated simplicity.

GIS:
- one halyard
- downhaul
- mainsheet
- traveller

Dabchick:
- 3 stays
- two halyards
- mainsheet
- 2 jib sheets
- downhaul to tension the forestay on the jib
- kicker (operated from the mast)
- outhaul (operated from both sides of the boat)
- cunningham (operated from both sides of the boat)
- bridle for the mainsheet

MIK's Litte Sexy Daysailer (LSD??? ):
- kicker
- outhaul
- cunningham
- mainsheet
- bridle for the mainsheet

Questionmarks of course. How would a box mast go with a Laser like luff (it is on the drawings for the GIS...). Boom perhaps a T shape. Both would be relatively easy to make. And didn't Herreshoff say that box masts are more efficient?

Sail: a modern shape will battens supporting an extended roach. Perhaps to be produced centrally to keep costs down.

The OZ-racer / GIS foils go a long way and I don't think it is worthwhile to try to better these.

Very much looking foward to MIK's first sketches!

Good reading on the Herreshoff, but he was wrong. I think his argument was that the mast could be a bit smaller or have less visible cross section relative to the apparent wind.

The Square masts lose a bit of efficiency ... but gosh it's easier to build a reasonably light mast that way compared to the alternatives.

MIK

The alternatives I can think of:
- aluminum mast (as per the discussion above concerning Laser parts)
- carbon mast (this will be by far the most expensive option)
- bird's mouth wooden mast (one must have access however to either a good table circular saw or a table router, I for example own neither)

If going for the wooden option, it should be possible of course to offer two alternatives (box mast + bird's mouth constructed round mast). Weights would be in the same range I think.

There might be another alternative you haven't seen yet ... hehe

And it is waaaay more sexy.

MIK

Getting very curious here!

How long are you going to keep us in suspension?

As long as I want to.

But i had better get some info together in the next few weeks. It's possible that nobody will like it at all.

I am still trying to work out how to make it reasonably cheap despite some high techy aspects.

MIK

This lugsail yard was made from 4 x 1/4-round ceiling corner moldings from a big store. Glued pairs together, then a layer of glass tape inside as I had it, then glued the halves together and the two quarter-round strips to give it a better shape, and the 12mm OD aluminium tube as a track for slugs on the sail. Cut a slot for the track with table saw. Then covered the whole thing with a fibreglass sleeve to make it a smooth oval shape. It is pretty stiff, but bends enough with the downhaul to flatten the sail. You could simplify it by using only the 4 ceiling corner mouldings. I made my mast the same way with larger mouldings. They made an 8 sided shape, easily planed to 16 sides and rounded. The mast was covered with 3 layers of carbon sleeves and a protective layer of a light glass sleeve (all from Soller Composites in the US).
Peter

Originally Posted by Boatmik

As long as I want to.

But i had better get some info together in the next few weeks. It's possible that nobody will like it at all.

I am still trying to work out how to make it reasonably cheap despite some high techy aspects.

MIK

Sounds very exiting and promising. Will eagerly await your solution.

One more rig alternative I can think of is one combining the mast and the sail in one: a wing mast or, taking it even further, a rigid wing sail rig....

Originally Posted by Joost

One more rig alternative I can think of is one combining the mast and the sail in one: a wing mast or, taking it even further, a rigid wing sail rig....

Hi Joost,
There is not much more complication to go two piece with the wing, and using reasonably lo-tech materials like has been done with this Sunfish. Much more efficient. You don't really need carbon.
Attachment 208087

Another way of making a spar is using Andrew Linn's faux birdsmouth method and epoxy for the glue because it is gap filling. The advantage of the faux birdmouth method is that you can use cheap 1/4 inch material and if you don't have a table saw, you can plane the angles.

Faux Birds Mouth Mast - by Andrew Linn

Howdy,

While I like the ingenuity of Andrew's mast I don't like it so much because it isn't tapered. Too much weight at the ends and also it doesn't look right.

But I'll give you a hint of what I'm thinking about the rig.

Concrete Slab Insulation - Woodwork Forums

Frank fathered the development of modern Australian style hulls and very sophisticated rigs.

There were lots of people helping with the feedback and development cycles but certainly he was amongst the instigators and also certainly the one who worked most consistently.

Most of his advances were achieved with wood and string .. and maybe a bit of wire.

Later they got caught up in the whole high tech thing. But all the advances ... as is my hobby horse ... is that EVERY major development in sailing performance has nothing to do with materials.

The METHODS led to jumps in efficiency of 5 or 10 or 15%.

Materials, on the other hand have been responsible for a tiny percentage (maybe about 2%?) of performance but also for the 400 to 1200% price blowout for conventional sailing dinghies and catamarans.

MIK

A foam insulated concrete mast...
Or a cork covered one...
(Ok... I'm not very good at hints ! )