Mast location advice sought

No problem. The mast postion guide is for sloops of the usual proportions of fore triangle and mainsail. The important thing, as you suggest, is the position of the center of effort relative to the center of lateral resistance.

Tim Dunn
Arlington WA

 

Jimthom says:
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I am planning to move the mast aft from station 4 to station 5(approximate), but keep the CE of the sail plan where it is by altering the sail plan to a cutter rig. The leading edge of the keel is fixed around station 4.
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See my answer to this question in the boatbuilding newsgroup.......

 

Seems there is a lot of merit in a rearward rig with a big genua and small, double-sided, rigid main, in conjunction with an mostly unstayed mast, where the main essentially is a flap to the genua - double rear stays might be needed to keep the front stay rigid!

 

Is it all valid for Mulitihulls?

Is the placing of the mast done "exactly" the same way when designing multihulls?
More specifically a cat rigged cat?

Cheers

Patrik Elfving

 

Catamarans have a different balance problem than monohulls. With both hulls submerged, the resistance of the windward hull makes the boat round up. With the hull flying, the CE of the sails moves outboard, which tends to make the boat round up, but the resistance of the wndward hull disappears.

 

visitor

[Does anyone know how can I get the deck or design plans for Herreshoff Marlin or Fish? I heard they post on the MIT (Massachussets Inst. of Tech) website. If you know any information on how to get this plans, please email to igomes@usc.edu Thanks!!!!!!!!!!!!!!!!!!

 

The extra roach area is often pretty much right above the center of area, so the effect is not as great as might be feared. The additional heeling effect may affect balance as much or more than a shift in the CoA.

 

The position of the mast is dictated by a number of considerations.

Sail plan: cat, sloop, 3/4, yawl etc
Where and how the mast will be stayed; makes sense to put mast near the widest beam.
Foresail/main proportions, roach aspects; fashion and function go back and forth here.
Maststep arrangements; makes sense to concentrate engineering around centre of boat.
Mast weight.

I certainly have not exausted the considerations, and all of these have to be balanced against each other.

Isn't yacht design wonderful?