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Cirrus Icon Development

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Medway Maniac View Drop Down
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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Topic: Cirrus Icon Development
    Posted: 05 Nov 10 at 10:40am
Yes, I wasn't saying the Scorpion was quick by design, more by accident in that the hydrodynamics benefitted from the easy-build considerations. Ents & Wayfarers might have been more pleasing to the eye in those days, but I doubt their bows are quicker.
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 05 Nov 10 at 11:20am
The main chine (which stops around the mast) is relatively high, which works really well in the NS/Icon prototype.  The secondary (aft) chine is just there to improve manners whilst high speed planing I guess.  I don't really think that you want chines in the bow from a performance perspective, but can see they would help create developable panels to ease construction.
 
Anyhow, it won't be long now before the theory can be put to the test!
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Post Options Post Options   Quote RS400atC Quote  Post ReplyReply Direct Link To This Post Posted: 05 Nov 10 at 12:51pm
The chines are a bit of a surprise, but I suppose it has a lot of freeboard compared with 'boats that may or may not be skiffs'. Can't make up my mind what effect it will have in light weather. In very light stuff it probably won't be an issue.
I know the black gel is for mould tools, but it's a nice change from RS 'utility van grey'.
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Post Options Post Options   Quote blaze720 Quote  Post ReplyReply Direct Link To This Post Posted: 05 Nov 10 at 6:04pm

The ‘rear chine’ appears to be much more of a feature than it is in reality.  I guess the fairing work on the plug, colours and the photography have made it appear very prominent.  

This hull is really about compound curves and these are quite pronounced in some areas, even towards the back.  It will be better to judge it when in a standard gelcoat colour.  ICON is NS14 and Merlin influenced but longer and the bow in particular is ‘over-length’ compared to both.  We wanted the mast a bit further back in the boat so we could enlarge the jib  - it is being optimised for its 2-sail rig after all.  We wanted plenty of sail area to drive it fast off-wind and the large(r) jib keeps the C of E low.  Coupled with the very adjustable carbon rig this means upwind will not be a fight of endurance in breeze.

The mast finally selected is a 50mm carbon ‘stick’ being developed by Aarvark  and we plan to marry up hull and rig later this month.   Masts will be finished in white – it is more practical than a clear finish for something that is in the sun whenever it shines.  (If I wanted to varnish things regularly I’d get a sideboard !)   Anyway it fits the ICON philosophy.  You can still admire the boom though if you are a carbon freak !  

Mike L.   (aka Cirrus) 

PS if you are interested further join the 'yahoo group' - search on Icon-Sailing 



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Post Options Post Options   Quote andymck Quote  Post ReplyReply Direct Link To This Post Posted: 05 Nov 10 at 6:30pm
Mike

I like what I see so far, but why a boom launched jib stick. We tried these in the 80's in 12's and they are fine to a point. The advantage of the mast launched system are two fold, the first is the reduction in black eyes you gets from jib pole, especially if it is going to be rope controlled (unlike the Merlin) the second is the massive boost in performance you get when reaching from leech control. This also gives the crew a lot to do downwind, that is lacking and actually painful if you have to do it by hand. The boom launched systems never really allowed this to happen adequately. There is no mystery why all the classes that allow this have graduated to mast launch jib sticks, unless you really have redesigned the wheel.

Andy
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Post Options Post Options   Quote blaze720 Quote  Post ReplyReply Direct Link To This Post Posted: 07 Nov 10 at 8:29pm
Andy

No decision made on this one .... we want to sort the core rig first.  Only concern would be that  that the jib wil be relatvely large and the pole required would be pretty long.  There is a good argument for not disturbing the airflow around the slimline mast too much !  ... but we will be trying it anyway on the pre-production ICONs - one o f the very last things to finalise.

Maybe we keep the rule 'open' on this particular aspect and allow freedom to have any jib-stick system.  What do you think ?  The SMOD model does not have to be totally tight - maybe we just keep it to the main boat elements,  plus ban 'extra' controls or moving 'given' fittings and allow limited freedom.   Main sheeting systems could be 'open' as well, number of purchases on mainsheet 'open' and so on but spars/foils/sails/basic fittings (ie the expensive bits) are kept strictly controlled to prevent unlimited cheque book racing.   After all we are going to allow the choice of 'thwart' or 'no-thwart' already ....

Mike L. (aka Cirrus Raceboats)
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Post Options Post Options   Quote Medway Maniac Quote  Post ReplyReply Direct Link To This Post Posted: 07 Nov 10 at 8:59pm
I'm totally in favour of allowing freedom of choice on things that don't involve great expense, unless, for example,  they lead to a boat which is only marginally quicker (and are therefore nonetheless 'must-haves') with the mod but make the boat significantly less convenient/comfortable. For example the rule-change to allow slot gaskets on Wayfarers which improved the boat's sailing qualities not a jot but now involves tedious routine maintenance.
 
It was the anal fixation on identical one-design boats that finally deterred me from joining the Wilsonian class-racing in Laser 2000's last year. Had the simple choice of an aft-bridle mainsheet been allowed (making that boat much more convenient to sail), I'd probably have gone for it. (Incidentally, I sailed a Blaze with forward-mounted off-the-boom sheeting and aft-bridle recently and found it a really winning mod, at least in the light stuff)
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Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 07 Nov 10 at 9:21pm
I've never sailed with a mast launched jib pole.  Are they easy to set/gybe/stow/maintain? I know the standard in the N12 is pretty high, but is a mast system manageable for simpletons like me?  I can see in some ways it might be even simpler, because it is always attached, but on the other hand because it can be used across a wider range of wind angles presumably it needs more trimming and is in use for a good proportion of the race?
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Post Options Post Options   Quote drifter Quote  Post ReplyReply Direct Link To This Post Posted: 07 Nov 10 at 9:41pm
Two-sailed boats-flyaway pole is a no-brainer. Easy to use and cheap to build. Grads and Albacores have used them for years. Even Ents now allow them. Do it!
Stewart
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Post Options Post Options   Quote Merlinboy Quote  Post ReplyReply Direct Link To This Post Posted: 07 Nov 10 at 9:47pm
Originally posted by Peaky

I've never sailed with a mast launched jib pole.  Are they easy to set/gybe/stow/maintain? I know the standard in the N12 is pretty high, but is a mast system manageable for simpletons like me?  I can see in some ways it might be even simpler, because it is always attached, but on the other hand because it can be used across a wider range of wind angles presumably it needs more trimming and is in use for a good proportion of the race?

I used them when i sailed Albacores, its a stupidly simple system.  Much, much better then the old boom mounted system you used to get on N12's.  It also has the benefit of giving you some control on a reach.  All you do is pull the string and the pole pulls down to the mast eye, when your ready uncleat it and it shoots back up the mast...Simples
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