How wide?

In the multione rules it allows up to 48" beam, now that is seriously wide considering there are few (if any?) full size multis that are wider than they are long, i guess structural problems if not rules would limit the width, judging by the way the 60’ jobs fall apart. But is there any real advantage to a boat that wide anyway apart from the extra righting moment, some say that it makes the boat harder to tack, but i can’t see how that works apart from the fact you are presenting alot of windage that could stop a lightweight boat mid tack. For a non foiler what is the optimum width?

If its not blowing it sucks!

I’d go for max beam foiler or not but the rational behind this beam was that the foils are 8"-12" wide so subtract that to get a beam of 36" to 40" ama cl to ama cl. However now we know that the foils don’t have to be mounted in the ama so on my F48 and mutiONE the ama’s will be max out.
I don’t believe beam makes any difference or very very little to tacking ability on a properly designed boat. But that means on a tri you can’t have all three hulls in the water at the same time.Then the tri is essentialy a 24" wide cat. On foils there is nothing but improvement in having max beam…
On either an oversquare “normal” cat or tri the biggest potential negative to real wide beam would be moments generated about the lee hull in any waves–
Regardless of beam the most serious multiONE and F48 problem is pitch pole and you must incorporate a solution to that if you want to get around the course upright…

Doug Lord
High Technology Sailing/Racing

Thanks Dick but I just told you a couple of weeks or so ago that I don’t produce PBS systems (for the time being )to use on multihulls. And I think Ian Sammis may be working on a really good system.
As to beam: on a trimaran foiler or not the outside hulls can be made smaller up to a point-so some of the anticipated inertial problems wouldn’t be very great. On a foiler like the F3(72" wide and 56" long) it tacks on a dime when on foils; it also does not pivot on the main hull since the lateral resistance is being generated on vertical fins thru the ama’s.
On a non foil multihull I believe beam should be max because it can be and because it works well. But you MUST address the pitchpole issue or the boat will be upside down in winds over 8 in the blink of eye. And you already know what those solutions are…

Doug Lord
High Technology Sailing/Racing