proa rigs

[Alex.A]

Proa's seem to sport quite a variety of rigs with c of e varying quite widely in positions..... Harry / Atlantic / EQL seem to be more in line with cats, while pacific seems to a lot more fwd.... Why?
Also varies with rig type and the hull weight balances.....
No baseline to judge by and even the "experts" seem to have to experiment lots to find the sweet spot.....

[gonzo]

A traditional proa will shunt not tack. The mast leans forward. However, when you shunt the mast leans the other way.

[rob denney]

Originally Posted by Alex.A

Proa's seem to sport quite a variety of rigs with c of e varying quite widely in positions..... Harry / Atlantic / EQL seem to be more in line with cats, while pacific seems to a lot more fwd.... Why?
Also varies with rig type and the hull weight balances.....
No baseline to judge by and even the "experts" seem to have to experiment lots to find the sweet spot.....

Weed out people trying (and usually failing) to recreate traditonal proas and people who do not want to go to windward. You are then left with variations of the marconi rig. Then remove those who don't require an easily handled rig or who don't mind breaking a mast or capsizing when caught aback and you are left with unstayed ballestron, una and schooner, perhaps with a foresail for reaching on the latter.

Rob

[Alex.A]

For the "traditional" type / pacific - why does it need to be so far fwd/ have a lot of lead?
Even with a marconi, the foresail is necessary.....
The hull is balanced around the centre - even if altered to bring the bow up - for each direction. While the ballestron/easy seems ideal - it isn't simple or cheap and even on harry's still has a few issue's......
The weight of the ama seems to be at the heart of the issue - ie the harry etc are cat - like enough to have similar rigs... but the light ama of the pac proa seems to be different to all of the above but it doesn't act like a tri or a mono either It also sails as a mono when flying the hull but i guess you set it up for the ama in the water....

[cavalier mk2]

Hi Alex, with many newer proas the CLR is changed when shunting to get the lead as the daggerboard/rudders are raised and lowered so the rig doesn't need to shift forward. Remember the traditional types were sailed with movable ballast (lots of crew). for stability making a light ama appropriate. There are plenty of people working with crab claw rigs you can find on the internet, properly set up they go to windward well and are more effient on a area basis than other rigs. Shunting isn't easier however...

[gonzo]

The mast pivots and tilts forward when you shunt.

[Alex.A]

While i am interested in the crabclaw - it is isn't ideal for shunting..... shorthanded or on a smaller boat. I like the proa concept but rig and rudders remain an issue.... i am also trying to get away with not using daggerboards This is probably the main problem.......
What works on small models doesn't necessarilly translate into reality

[rob denney]

Originally Posted by Alex.A

For the "traditional" type / pacific - why does it need to be so far fwd/ have a lot of lead?

Because they steer with a paddle, which is very hard work. And because they have huge rocker and slab sides so the bow goes down and the clr moves forward.

Originally Posted by Alex.A

Even with a marconi, the foresail is necessary.....

My 7.5 sails perfectly well with just a mainsail (has no headsail), as do the easy rigged proas. Shunting can be a bit more difficult, but easy enough if you are aware of what you are doing.

Originally Posted by Alex.A

The hull is balanced around the centre - even if altered to bring the bow up - for each direction.

The hull is weight balanced round the centre, but when moving on a reach or upwind, the clr moves forward, same as on any foil. This is countered with a single rudder or dual rudder with the front one aligned with the flow.

Originally Posted by Alex.A

While the ballestron/easy seems ideal - it isn't simple or cheap and even on harry's still has a few issue's......

What issues? And what rig, apart from a second hand one, is cheaper for a fast boat going out of sight of land.

Originally Posted by Alex.A

The weight of the ama seems to be at the heart of the issue - ie the harry etc are cat - like enough to have similar rigs... but the light ama of the pac proa seems to be different to all of the above but it doesn't act like a tri or a mono either It also sails as a mono when flying the hull but i guess you set it up for the ama in the water....

The ww hull weight/drag is the least relevant aspect, within the limits of what I have tried so far. In the same way that beach cats' balance barely changes when they fly a hull, my 140 kg 7.5m steers just as well with my 80 kgs on the ww or lw hull.

Originally Posted by Alex.A

I like the proa concept but rig and rudders remain an issue.... i am also trying to get away with not using daggerboards This is probably the main problem.......

What issues? Daggerboards are a recipe for hard work and imminent disaster. Beam mounted rudders are a much better option, although we are still learning how far inboard the beams can go.
rob

[Alex.A]

Thanks Rob.
Was thinking of a cross-over rudder/paddle - along the lines of Wharrams ethnic range..... either/or. No rocker or slab sides I want the hulls to do enough that i wont need boards.. High cp & flat bottomed - similar to your concept Rob. As no need to tack - should work fine
The issues were read from older yahoo forums - got you to answer tho
Crab claw - yes i know most (you Rob) dont like them - but as a DIY rig for an ameteur like me, it will be an ok place to start.... if i hate it i can always change it later.
Still playing/testing/learning - it never seems to stop

[boybland]

From the internet pictures I have seen, I like the simplicity of a schooner rig with two high aspect identical mainsails, that just swing round the back of the mast, sorry no idea what they had under the water, just remembered it looked very nice.

[DarthCluin]

Probably CLC's Pacific Proa (Mbuli). Go here:
http://www.clcboats.com/shop/boats/w...ser-plans.html
I think the one with the Flettner rotary sail is boundlessly amusing.

[Dryfeet]

I think the Flettner Rotor is a very creative idea! I'd like to know more about THAT one!

[DarthCluin]

The principle used by the Flettner rotary sail is the Magnus Effect. Sadly, it is not as efficient as using the same motor to turn a propeller to push water. Wikipedia has a very good article here:
http://en.wikipedia.org/wiki/Magnus_effect

[terhohalme]

Originally Posted by Dryfeet

I think the Flettner Rotor is a very creative idea! I'd like to know more about THAT one!

Sadly, it is not a sail, just a propulsion method for the engine...

[ThomD]

Fletner is being used by those guys combating global warming with searunners. Marples is involved, so I have to wonder how hopeless the rig is... on a small boat did they pedal power the rig?

Norwood was a great proponent of the pyramid rig, can't recall why, any ideas on that?

I would be a little cautious Alex about any testbed project of any size above a skiff. I am not convinced a let's chase ideas approach is as good as a solid plan that is executed, even if the plan is not perfect. Michael Schacht's proa comes to mind as a sincere project that never got working, and the other extreme are Rob's boats that however successful are never finsihed and sailing, which is just fine if the enquiry is the main thing, but not if using them is any part of it. It is pretty easy to see ten productive yeears slide by on boatbuilding projects.