"semi-stayed" riggs

[champ0815]

Well, deck clutter is not a big problem on a multihull since there is much deck space... .
The problem with a free standing mast on a catamaran is the (changing) bending load into the beam on which the mast is supported. The (constant) compression load of a stayed rigg seems to be far less problematic but still not desirable for the physics of the beam.
Therefore the idea of a supported "free" standing rigg came to my mind to circumvent both problems especially because of the cheap availability of used surf masts which are lightweight, designed for the purpose and have a sufficient length for a small cat of 4 to 6 meters.

[ThomD]

fair enough. The only thing being that on boats this size, the beam loads are not difficult to provide for, if the boat supports people... and the winning rigs are all over the place either cheap or second hand.

[idkfa]

http://www.gohoot.com/gallery.html

[rob denney]

Originally Posted by champ0815

Ok, I see the topic has moved a little bit in an unexpected direction... .
Nevertheless, the sliding gunter is an interesting concept for a hybrid rigg between stayed and unstayed.
Am I right with the assumption, that the "sliding" refers to the gaff which is movable in vertical direction without changing its angle to the mast?
If so, I see the advantages for reefing, instant depowering in gust response and the availability of fore and lightwind sails.

Has anybody ventured in the direction of telescoping masts (where the "gaff" slides in the mast for reefing)? This seems to me the next step in this direction, solving the problem (if there is any) of gaff tension... .

I am putting a telescopic wing mast on my current boat. Mast starts as soon as the infusion table is finished. A gunter is an option, but the track and attachment to the mast have to be very strong (can't just use a halyard as it falls away from the mast when reefed), and there is added turbulence behind the mast when it is lowered.

Originally Posted by champ0815

And to come back to my initial questions:
Since nobody challenged the feasibility of using boom height supported surf poles on small multis, what about the upscaling of this idea to larger boats? No advantages seen, neither in rigg maintenance nor in weight of an adequately designed mast (in contrast to a real free standing pole) or in support and compression loads on the beam of a cat?

Small boats, it will work, but deck space will be inhibited, large boats you have large horizontal compression loads, lots of things to trip over, maintenance and replacement issues with the wires, and you still need a pretty substantial mast. Plus, you can't hoist, lower and reef on all points of sail.

Dryfeet,
What other information on the one ruddered cat did you want?

rob

[Dryfeet]

Rob,
My primary concern is different helm loads on either tack. Perhaps neutral on one tack if the lead is right but either weather helm or lee helm on the other tack. Proas can be made to compensate for the ww hull drag as it is constantly to weather. A single rudder on a tacking proa or cat will alternately fight hull drag or not depending the tack, it would seem.

Couple those with the rig acting like an off center prop and I just have questions. Perhaps the effect is either negligible or a non-issue?

[rob denney]

Originally Posted by Dryfeet

Rob,
My primary concern is different helm loads on either tack. Perhaps neutral on one tack if the lead is right but either weather helm or lee helm on the other tack. Proas can be made to compensate for the ww hull drag as it is constantly to weather. A single rudder on a tacking proa or cat will alternately fight hull drag or not depending the tack, it would seem.

Couple those with the rig acting like an off center prop and I just have questions. Perhaps the effect is either negligible or a non-issue?

Once a long skinny hull gets moving, the helm is pretty neutral. Definitely turns faster in one direction than the other, which would not be a problem with a single, central rudder. Much better steering would result from two central rudders, and no daggerboards.

rob