The process of rig design?

So I was wondering lately about rig design, the old question, which came first the sail or the mast? When you are designing a rig do you design the sail and then worry about getting the mast to fit it, or do you start with the mast and spreaders and try to get the Sail to fit them? (mast bend offsets and all of that) (don't worry, I'm not doing either of these things my self) its just something I am wondering about, I'm interested in the process right now, not the science.

 

Sails on ancient designs were basically designed by accident, they put something up and it sorta worked. By trial and error they found various shapes and rigs that could improve their performance. Traditional rigs for wood boats, gaffers, etc. are still designed the same way, by tradition of historically what has worked well (i.e. not a lot of science).

The modern design process is to first determine what you want in terms of performance, function, etc. Design the sail plan to match, and then design the mast and rigging around the sail design. The mast and rigging is only there to hold and control the sails, so the mast should always follow the sail plan. Sometimes there is a lot of science involved, like on advanced modern open class sailing rigs or rigid wing designs, and sometimes following traditional patterns and formulas for "conventional" designs.

 

I can't say I completely agree with this. Developing a boat is a complex process, and reducing variables is critical to getting a functional solution - and this is more and more critical the higher you go up the performance scale.

Sailmakers for one design and development classes know various masts quite well. Ask a 505 sailor about the differences between a Superspar and a Proctor. Then ask him which sailmaker's products work best for a given type of tube. You will get very clear opinions regarding North Sails on Proctors or Glasers on Superspars.

This area is all science and experience and there has been a body of work built up learning how to tune and control various spar types from both a standing rigging perspective, and as a dynamic component in rig control, just like a vang, outhaul or cunningham.

FWIW, I would pick your spar, and then find a sailmaker who really knows the tube and it's characteristics. At that point your sailmaker is able to design his sails in the context of the spar, not in spite of it. In your case, talk to Bill Hansen about what he would do in the exact situation if he were in your shoes - he'll quickly let you know where to start, and his sails are going to be developed after the mast flex and design issues are known. It is far easier to tune/recut and adapt a sail than it is to tune, adapt and re-work a spar.

 

Mind Reader ........

Thanks Bistros