Well they are money machines in a sense. A new one all kitted up is $50K but the thing is they last for ever. Sponsers and race money help here though. I think 5ohs and i14s are crazy with the money side. Mind you that isn't going to stop me having a go!
T_E
I say thank you for the long reply, I find it interesting to hear this stuff about the skiffs. i've been well aware of them for a long time. I just didn't know that boats like the 49-er were not considered real skiffs. Additionally I find you commentary alot more interesting then the skiff class webpages. You are providing alot more detailed info and info that allows me (at least) to get a better feel for the balancing that is included in designing a better skiff. Afterall, this is part of any boat design.
I can understand the absolute need for the design to help in the area of control. As said, when I sailed the 49-er I noticed that any help here is a major point. It allows you to drive it much higher by not having to keep a significant safe margin. Again this is the interesting balancing act and the skiffs are on a totally different path in the way of rig development.
Clearly the skiff rig tension is heaps more then what I personally found on, again, boats like 49-er. So I think I admitted to that earlier in this thread. And yes this does provide an engineering challenge. Although I do still wonder why exactly this high tig tension is needed. What is its beneficial effect or what is causing this to be necessary ? Do you know ? On the 49-er it appeared that that the designs tried to bend the flexible mast into a stiff lower section by the yielding method of buckling. This does require alot more tension then bending a mast by
cantilevering
it. I feel cats are mostly using the last method and that the stiff for aft plane doesn't require rig tension to sufficiently fix the bottom part of the mast to a given curve. That and the fact that a skiff rig can never accept loose shrouds as that would negative impact on control by having a mast that can independently move relative to the platform. I'm very interested in your ideas here.
Ohhh, I do very much respect these classes and all as a matter of fact. I'm just also a digger and question everything. I want to know how it really is and you don't get there by asking softball questions. I also fear that at alot of times my way of writing can be intepreted as being respectless, but in basis it truly isn't. Although I do have a streak of using biting sarcasm in my writings alot. That comes from my upbringing, was considered a sport in the (very much loving) family I grew up in. And sadly this was also the case among students and friends at the University I went to after leaving the family. Even in the Netherlands themselfs these have a reputation for being like this.
I'll try ! But also know that I never mean that much by it, certainly not disrespect. Disagreement with the points stated yes that it signales but not hate or disrespect.
Wouter
So why not taper the wind mast ?
John P does it on his F16's and some of the old T's had tapered Alu masts.
Hi Wouter,
I don't think that the rig is the major contributing factor to a monos upwind performace, or lack of..... Just don't think they are as efficient as a cat in using the boat's weight as righting momentum. The only way I see they can minimise the disadvantage is by using wings (skiffs) or canting keel (yachts). Please read what I wrote previously and add your thoughts.
A cats righing momentum is the weight of the platform and its rig from the windward side of the leeward board...... plus the crews weight, 8 foot (or just under 10 foot for a T) out from the pivot point.
Looking at this, the cat has a lot more righing momentum and uses the weight of the boat far more efficiently.
As for skiff rig tension, I believe that the reason for the high rig tension is to give the rig enough prebend to support a mast head kite without inverting the rig, whilst using a lighter / smaller mast section.
It also allows a bit more gust response than a stiffer wing mast. A mono does not harness and transfer the energy from a gust as well as a cat, but tends to transfer it more to heel, thus the need for better gust response.
Sorry T_E, but if monos were to maximise their efficiecy, they will have to strap on another hull or 2......... or hydrofoils <img src=
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John P does it on his F16's and some of the old T's had tapered Alu masts.
They will still need to overcome upper mast stability. I believe it would be achievable by tapering the mast and using 3 to 4 overlaping sets of diamonds to achieve a prebend with enough support up top.
Development cost time and money....... Somebody will do it eventualy. May be some cat guys need to jump ship and show them <img src=
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Yes I understand your earlier comments.
My line of reasoning (and it is just that) is that when a craft is limited by righting moment (as surely the mono's are) then a more aerodynamic efficient rig will allow them to create more drive for the given righting moment AS LONG AS it doesn't also include making the mast (leverage) significantly greater.
Pretty much efficiency can be deduced down to a ratio of devellopped drive against devellopped sideways force that causes heel.
I also seem to recall from the Miss Nylex design article that 40 % of the total drag of this C-class cat was the direct result of aerodynamic drag of the sails. It was the single biggest drag factor. I'm not sure how this translates into planing skiff designs. Maybe here the hull drag is significantly higher percentage wise. T_E comments seem to point in that direction.
T_E comments about the (control) compromises is really the only factor then can foil up the above reasoning.
Stephen, you comment :
Combined with my 5%-15 % example seem to suggest that it may pay off to drop the mast head spi for one that comes lower on the mast (as with cats) if that allows a sufficiently better upwind rig.
I wonder whether losing 1 mtr on the luff or so will loose 15 % downwind performance. Also going down on spi hoist height really quickle stiffs up the mast top. There is a very powerful 3rd order (power) relationship there. Going to the mast top is not a straight forward must-have.
This could be a case analogue to
slow down to win
, the well know manouvre when rounding the bottom mark with alot of other boats.
All interesting stuff
Wouter
I wonder whether losing 1 mtr on the luff or so will loose 15 % downwind performance. Also going down on spi hoist height really quickle stiffs up the mast top. There is a very powerful 3rd order (power) relationship there. Going to the mast top is not a straight forward must-have.
This could be a case analogue to
slow down to win
, the well know manouvre when rounding the bottom mark with alot of other boats.
All interesting stuff
Wouter
Such as the 12 footer with the A Class rig I posted above...... Don't worry Wouter, they'll catch up one day <img src=
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i can name a sail boat under twelve feet that goes overt 25 knots, and it doesn't suffer to windward although it has no daggerboard.
windsurfers and kiteboards both have that capability and they don't cost $50,000.
You just can't apply common sense to a topic like this.
Such as the 12 footer with the A Class rig I posted above...... Don't worry Wouter, they'll catch up one day <img src=
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I'd think that nosediving would be made worse by the 'A' rig, yes?.
Hey Jollyrodgers,
I said TWO man craft. Read it again champ.
T_E