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Old 17-06-2015, 13:59   #1
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Design of the sail rig?

Before contracting to purchase any cat in the 50 foot range, would it be feasible to get some data on the rig and sails to compare with other rig and sail makers? To determine from the start the most efficient setup possible. Has any done this in the past?

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Old 17-06-2015, 16:12   #2
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Re: Design of the sail rig?

Copied from MC2-60 sails and rigging:
On many cruising catamarans, sails are cut to represent a compromise between upwind in light airs and downwind in medium breeze. While we understand that such sails are perfectly adequate for the cruising catamarans targeting absolute comfort and easy sailing, we took the view they donít belong onboard high performance cruising catamarans.

Also what have the cruising cats out there learned from having carbon fibre mast?

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Old 17-06-2015, 21:34   #3
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Re: Design of the sail rig?


It depends on what exactly you are asking for. Rig design is its own science, you can obviously contact one of the engineers at Hall or Southern and get much better answers than you would from here.

As for efficiency... Mathematically the most efficient rig is a single rigid wing sail. With an extremely high aspect ratio. The C class catamarans are probably the most extreme example of this. Their only limitation is on sail area, so they have designed to make the most of the sail area allotted.

Beyond this extreme, high aspect large roach mains with small non-overlapping jibs, and large asymmetric spinnakers are the current best trade off for a performance boat.

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Old 17-06-2015, 22:44   #4
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Re: Design of the sail rig?

Most importantly, you need to define what you mean by "efficient". As well as how well you want a specific boat to perform on varioous points of sail, over a given range of conditions.

Basically drawing up a "must have" set of performance polars. And then with this, sit down with a boat's designer, & see if such is even possible, given; the hull designs, rig design, structural strength built in, loads, weight & drag (water & wind).
Though unless you start a boat's design from a blank sheet of paper, it'll be pretty impossible to meet all of these goals. As everything which goes into a boat's design is interconnected, as well as being a series of compromises.

Your best bet is likely to get a set of polars from various boats in this size range, including what sails they were generated with. Ditto on how heavily they were theoretically loaded when the polars were calculated. And then compare them/use them as rough guides as to what'll likely work in terms of sail combinations on the boat(s) which you're considering.

If you have such information, & hire a good, performance sailmaker, then he can help you to draw up a recommended sail inventory, so that you get the best performance out of the boat on all points of sail. And, he should provide you with several variations on this, pointing out the pros & cons of each inventory.

Or as the lingo goes, you want to make sure that there aren't any "holes" in your inventory. Meaning that you don't have any points of sail, or wind ranges where you don't have sails to keep you moving well.

Multihull, or mono it doesn't matter, the concept is the same. And a very good example of a sail chart showing what sails their boat uses in order to perform & handle best on varying points of sail, & wind strengths, is shown by Beth Leonard & Evans Starzinger here Sail Combinations
Also, sometimes you'll see similar information presented in graph format, especially if you go to a sailmaker's website, like say, North. As well as when you study the Polars for a boat.

And even when presented with this information, there are always more options. Such as "simple" modifications to one's rig. Meaning those which don't change any of it's base components or loadings.
But things like the following can be added; Solent Stays, Cutter Stays, 2nd Headstays (often made of Dyneema, & being detachable), Code 0's, Sprits - for bigger; jibs, & downwind sails... etc., etc.

It's dated, but
is a decent reference for the basics.
Materials & design have changed, ditto on platforms, but the "what" of what you want sails to do hasn't. Meaning, covering what points o sails, & what wind ranges. It's the ref. that I grew up with - a signed gift, courtesy of my bro.
- Ask your sailmaker if he has a recommended reference. Also, do some reading on all of the topics I hit on above, but from a racer's perspective/websites. As they have much more detailed information on the subjects, & it'll help to "school" you better on your queries. is a decent spot to start, as are many of the stories & links from the forums home site,

PS: If you want more "high speed" (detailed, & technical) references, LMK. And keep in mind, that despite all of the hype, the bottom line is, the basics really don't/haven't changed much. Except perhaps in scale & cost.

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