Cirrus Icon Development

Capsize & Inversion

I have always paid particular attention to this as it is very easy to have to much buoyancy in modern boats - Blaze / Halo are amongst the very best in this regard imho and we intend ICON to be similar relative to others out there.   This will be  partly due to the hull form and partly due to a tall (and 'sealed') mast.  This does not stop inversion but it makes it much less likely or rapid.

Frank B always argued that inversion was a good thing as the boat could not blow away from you.  Well we understand the logic but if it is possible to slow the ingress of water into the mast then again we regard it as a worth pursuing.  We aim not to prevent inversion just to make it much less likely and slower when it does happen.   This gives the crew a much better chance of quick recovery.

Masts - we have a number of very good carbon 'sticks' and they will be tried - but the NS does not hang onto the wing set-up for appearance - remember nothing on the NS is there for 'style' or 'show' - no stylists are/were involved  - all the features are for functional reasons and their worth has been proven.  If you go the 'stick' route you need more area for the same performance in our experience.

Mike L.  

Originally posted by blaze720   If you go the 'stick' route you need more area for the same performance in our experience.Mike L.

Then go for it - it´s cheaper and you can make the mast much
more gust responsive. Otherwise you´ll spend too much time on mast
development.
Time which you honestly haven´t got. I personally was not impressed with
that Tornado - type elipsoid mast at the DS.
Get as much sail area up above
as possible, which would be good for restricted and obstructed waters. You
´d be surprised how little extra "conventional rigged" sail area you´d need
to drive that nice fine hull along. Good luck and stop pontificating - unless
of course, it´s some marketing ploy

Edited by Slippery Jim

Hi Mike,

Saw you at the show but didnt want to interupt....and I didnt have long while searching for the best cover maker for my 400.

Um.... really like the Icon....

Bearing in mind all your previous remarks about masts etc, I would just like to say the first thing that came to mind (honestly) was...."oh carbon mast where is it?"

How shallow of me i guess

Lovely boat....good luck

Timg

 

Just a couple of other points, and then I promise to shut up!  Personally I like the square head on the ICON, because a. it looks good and b. it works.  It is the sail rather than the mast that does the gust response, but it is just as effective.  I do not believe you could put such a square head on a fixed mast without much more complex rigging a la 14s, 49ers etc, but maybe you could.  I think it would be real shame to  lose this visually striking part of the design.

How a boat behaves in gusts is also a function of more than just the rig.  How light and easily driven the hull is, and the quality of the foils also play an important role.  If the hull accelerates quickly, gusts will just make the boat go faster.  If it is a draggy hull, it will stagger. 

In fact, more completely, the hull and rig have to match, to have similar/complimentary responses to gusts. The ICON hull is based upon a successful NS hull form, and the one that carries weight best out of all the modern designs.  It is also one of the best in the light/moderate winds we get more of here, whereas some other NS hulls are perhaps more optimised to the fresher breezes the Aussies enjoy. 

By way of comparison, the hull is about 6 stone lighter than a Merlin hull.  To put that in perspective, for every hull length the boat travels forward it has to push aside about 80 pints less water than a Merlin Rocket does.  So the different hull has a different rig.

As someone who spends his working day creating fluid dynamic models of underwater bodies, and has sailed the protoype ICON for the last two years, I am convinced in both a theoretical and real way that the ICON is a step change in two-sail boat design.  But as Mike says, 30 mins on the water is the best proof.

Well obviously it's always the sail and mast together, but I think it's
fairly well understood that the square head can twist open more
easily?
I can't think of (m)any successful applications of an ICON style square
head on a fixed mast without going beyond the simple staying
system? I'm sure I'll be proved wrong though!
Interesting stuff...