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f14 limits!! #30494
02/25/04 09:11 PM
02/25/04 09:11 PM
Joined: Feb 2004
Posts: 1,012
South Australia
Darryl_Barrett Offline OP
old hand
Darryl_Barrett  Offline OP
old hand

Joined: Feb 2004
Posts: 1,012
South Australia
There are a lot of people who seem to express their "dreams" when it comes to "unrestricted" (apart from hull length, mast height etc) for a formula 14! When you really get down to the practical limitations for a design for a 14' cat, you soon work out that to put "a 150 odd sq ft jib, with a 150 odd, sq ft main, on a set of production hulls that like the Hobie 14, already carry more sail area as standard, than the hulls are able to accomadate efficiently ( the key word here is "efficiently"), that to carry more sail just makes the cat harder to sail, and in most cases, slower around a triangular course. To be able to "carry" sail, the first consideration is the bouancy, and positioning of that bouancy, of the hulls. They have to be as least resistant as possible to "drag" created by any sudden forces of forward motion that exert downward, as well as forward acceleration to the cat. If they aren't, then the bows "trip" (commonly known as pitch polling). They have to support one or two crew, not only inboard, but out on trapeze, and still resist "tripping" Remember you are sailing a catamaran, not a partially submerged submarine. The wider the hulls are placed apart on a cat (passed their ideal width for their length) and provided that the fore and aft position of the mast step remains the same, more and more insability and "tripping pressure is applied to the bows of the cat, so instead of creating a more stable platform, the reverse is generally the case. Wider placed hulls mean that you can resist the side way, lifting forces of the sails (and the lift of the hulls) more, but the fore and aft instability more than negates any advantage that you may get from that, and besides, we have comprehensive sail shape controls to control the "hull lifting" forces and convert them into forward motion ( that's what sailing is all about, converting wind generated "lift" into forward motion - regardless of which way the apparent wind is coming from). There is a global formula for assessing the efficiency, stability, and potentual performance of any sailing craft, and if any of the dimensions of that craft fall outside that formula, then it loses efficiency. As a very rough example, imagine a transperent sphere (ball for the less educated ha ha), place the cat that you want to check the potentual of, inside that glode. What you want to be looking for is that all the extremities of that cat will be just in contact with the inside of that globe, if the head of the mast is, but the hulls are not, then there will be instability greater than the potentual obtainable, etc, etc. What I am saying is that, when it comes to sailing fast, the old addage, "you can't beat cubic inches" commonly referring to cars, just doesn't apply to boats, just adding more sail often reduces the performance of a cat, its not what is added but how it is added, and it has to be added within the potentual performance perameters of that cat (if you want to "suck it and see", just step the rig of a Hobie 16 onto a Hobie 14 and you will soon see whether or not it works).
Yours
Darryl J Barrett

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Re: f14 limits!! [Re: Darryl_Barrett] #30495
02/25/04 09:55 PM
02/25/04 09:55 PM
Joined: Sep 2003
Posts: 84
ms/fl
fuzzy Offline
journeyman
fuzzy  Offline
journeyman

Joined: Sep 2003
Posts: 84
ms/fl
yo dude,
I do not quite understand your post.........Why dont we just see what shows up......could be very interesting....tr


A-class #19
Re: f14 limits!! [Re: Darryl_Barrett] #30496
02/25/04 09:56 PM
02/25/04 09:56 PM
Joined: Apr 2002
Posts: 695
Ft. Pierce, Fl. USA
Seeker Offline
addict
Seeker  Offline
addict

Joined: Apr 2002
Posts: 695
Ft. Pierce, Fl. USA
Darryl

“(if you want to "suck it and see", just step the rig of a Hobie 16 onto a Hobie 14 and you will soon see whether or not it works).”

While arguably the best selling catamaran ever, the Hobie 16 and/or 14 are known “pitch poles” looking for a place to happen. To limit design parameters because of inherent limitations of these two particular hull designs would be ludicrous.

If they are going to be your test platform, of course more sail area/taller mast/wider beam will be of little or no benefit. However a hull design conceived to utilize the increased sail area/taller mast/wider beam will benefit from the more open design rules.

Why this constant assault from the wings on creative expression in sail boat design. I am sure there were many nay Sayers when Hobie Alter first came out with the Hobie Cat.

Two thirds of the earth is covered by water…isn’t there enough room to let everyone have their own flavor…there always seems to be someone who is complaining that this guys boat too wide…that guys mast is too tall…the fellow over there has too much sail area…the one over there has a Hooter instead of a Spinnaker…and some guy is trying to buy a first place finish because he has “Carbon” in his boat and it’s too light…give it a rest…how about a little freedom of expression for a change.

Bob

Re: f14 limits!! [Re: Seeker] #30497
02/25/04 10:50 PM
02/25/04 10:50 PM
Joined: Jun 2001
Posts: 198
D
davidtilley Offline
member
davidtilley  Offline
member
D

Joined: Jun 2001
Posts: 198
Nicely put Bob.
While I am no fan of silly, baseless experimentation (wasting time and money), it seems in history the cynical naysayers, however educated, never made the breakthroughs. The guys with sense and the courage to try, and perhaps maybe the breadth of thought due to an "unchannelled" education and multi-discipline brought us the technological leaps.
An, well, hell, I loved my Hobie, maybe because it would suddenly violently pitchpole just up from a Beam reach!
Up and away off my Trebuchet!
Is it the same people who will moan about Portsmouth ratings untill everyone finishes in the middle of the pack? I suspect it is.

Re: f14 limits!! [Re: Seeker] #30498
02/25/04 11:26 PM
02/25/04 11:26 PM
Joined: Feb 2004
Posts: 1,012
South Australia
Darryl_Barrett Offline OP
old hand
Darryl_Barrett  Offline OP
old hand

Joined: Feb 2004
Posts: 1,012
South Australia
I have no desire to "limit" any ones experimentation with different configurations for, hulls, mast type and height, sail area, etc, etc, I say "bring them all on, and lets see just what holds up and is competative", What I wanted to point out was that to successfully "alter" an existing cat, or produce a new design, and have an improvement in performance, then you just can't alter one aspect of the cat without dramatical changing other areas of the cats performance/handling. It has to be seen as a "complete package" where the mast and sails match the hull and platform, as well as the rudders and/or centre boards, etc, etc. If you just put up larger sails, and if you have centre boards, then it is likeley that you are dramatically altering the centre of effort of the sails in relation to the centre of lateral resistance of the hulls, and you will completely change the steering characteristics of the cat ( some times to the point of uncontrolable weather helm or lee helm, often even more so on a centre board less cat). I would love to see ALL the extremes of designs actively compete in the 14' cat area, so that perhaps some one MAY just MAY hit apon a successful new revolutionary concept that has been sitting under our noses, so obvious that no one has even noticed it.
Darryl J Barrett


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