It is difficult to see how speed assessments are a bit too exaggerated when you look at some of the records for long distance races. Like the Miami-Key Largo Race, a 45-mile race, finished in under two hours. And the Sandusky Steeplechase, a 23-mile race finished in a record time of 57 minutes with the last mile or two being upwind. And the Key Largo Steeplechase, with a total of 110 miles being finished in a record time of 5 hours 40 minutes (and that included having to tack, or paddle, or at least lose speed through mangrove channels here and there, and altering course to avoid sandbars.)

A friend of ours has a video of him and skipper on a Tornado going 32-34 knots, with rooster tails shooting out a considerable distance behind the boat, for a short distance before they pitchpoled. And the same friend and another skipper have been clocked on a Nacra 6.0 doing 27-28 knots over a considerable distance. He is sure those were knots per hour, but even if these last two examples turned out to be mph instead of kph, they are still impressive speeds.

Sorry, Mike Fahle, please don't correct me again. I know it is just plain knots, not knots per hour (kph).

The Tornado may have been doing 32 - 34 kph (kilometres per hour)

No, Dermot. I just typed kph in error, because my brain was thinking "knots per hour," when I really meant just plain "knots."

Hello MARY,

The Tornado's owner may surely 've hidden powerful WATERJETS in the transom !!!!!

I surely believe 25-26 kt bursts of speed, but 32 kt...sounds so unbelievable !

Why don't you post the references of this video with reliable external bearings in such a way that the 30kt + assessment could be check ?

You know, the only way to break the 22 kt barrier is to plane on the rear half of a Tornado hull at +5° bow-up trim ( proven by spanish Olympic Team )...is there the case ?

Friendly,
Frenchie

Well, if their bows had been up and they had been planing, they probably would not have pitchpoled. Right? He said the boat was definitely going THROUGH the water. And, no, they did not use any artificial means of creating rooster tails. This is Henry (Enrique) Rodriguez, a close friend of ours who lives right down the street. He is right here at our home frequently. I was telling him about the thread that you started on the forum, and so he told me of his own experiences on the Tornado and Nacra 6.0. He campaigned for quite a while for the Olympics on the Tornado crewing for Robbie Daniel, and it was the two of them that were on the Tornado during the video. And the time records for distance races kind of speak for themselves. Henry was skippering and Hans Meijer crewing during the 110-mile Key Largo Steeplechase when they set the record of 5 hours 40 minutes on a Nacra 6.0, and it was during that race that they were clocked, via their GPS, at some sustained speeds of 27-28 knots. As I said, if he is wrong about the knots and it was actually miles per hour, that is still impressive. Definitely above your 22-knot "barrier" and no planing involved. In that particular race, even though most of it was a reach, there were also several slower areas, upwind sections, mangrove canals to go through with lessened wind, so they HAD to be going very fast at some points to achieve that overall time.
Maybe you are right on paper, but I don't think your theory holds up on the water.

Dear Mary,

I had done MANY VPP works for great multihulls and intensive tank tests, so I'm right on paper, but also over tank tests datas... the ONLY WAY to go faster than 22 kt on small catamarans is to plane at a certain speed...the frictional resistance increases at the square of speed, so at ( 27 ) x ( 27 ) = 729, you have 1,8 eight times the resistance at 20 kt = 400 !!!! and your power stops to raise as soon as you reach the maximum heeling moment, already gets at 20 kt...

I am quite skeptic...

Friendly,
Frenchie

Just reading the latest Yachts & Yachting.
In a review of the year, Mitch Booth claims that he was doing "about 30 knots" on a Hobie Fox flying a kite when he had his big pitchpole in the Round Texel Race, landing him in hospital for three days last June.

Frenchie,

Nobody is doubting your simulation and model testing experience and I don't doubt that to maintain 27 knots your calculations show that it would take 1.8 times the force required to maintain 20 knots. However, this doesn't say anything about it not being possible.

I think that Wouter's statement, that started this whole thing, was that a cat is capable of 30 knots. While perhaps it's unlikely that a beach cat could sustain 30knots, I think it's entirely possible in bursts of speed surfing waves.

Cheers,

Frenchie, I am a skeptic, too. Who are you? You are an anonymous poster on this forum. You have not given your name or your e-mail or your location or anything about you. Have you ever sailed a catamaran -- or any kind of sailboat? I have read all your posts and seen no indication that you sail at all. Oh, yes, I finally found one post where you said something about experiencing speed and getting wet on a Formula 40 and some other boats, but you did not elaborate on that at all. If you expect people to take you seriously, you have to at least exist and at least sound like you are a sailor instead of just a mathematician, or whatever it is that you are.
I don't know why people are being so polite to you and not arguing, because EVERYBODY knows you are wrong. Maybe I can get away with it because I am a woman. When numbers are put in the picture, men tend to get intimidated and say, "Wow, this guy must know what he is talking about. I don't dare contradict him." I don't know why Jake said he did not doubt you ( just being polite, I guess), because so far you have not given us any reason to believe you.
But I have been sailing cats a long time, and I know that what you are espousing is pure bunk.

You're right Mary - I was a bit soft. I should clarify:

I meant that I don't doubt his calculations that it takes 1.8 times more power to pull a cat from 20 knots to 27 knots. However, that says nothing about whether or not a catamaran can acquire, control, or manipulate that additional power requirement...The previous statment by Frenchie only says that it takes more force to go 27 knots than 20 - that's pretty basic. When you consider some of the variables like the angle of the sail plan and relative angle of forces relative to the direction of travel, the design of the sail plan, sailor weight & skill, surfing waves and such, it doesn't surprise me in the least to see cats achieve 30k.

Mathmatical models are great for evaluating differences in hull shapes, foils, etc against other similar models. However, they are not always real world. A mathmatical model is for comparing hulls and foils because if it is 20% off from real world, the next analysis of the next system, although also 20% off, still shows an increase or decrease between the two that allows you to evaluate the benefits of one system over the other.

I'm not calling Frenchie a liar either - his models are likely well designed, sound, and thouroughly tested - It sounds like he has the technical background to analyze the results - but I gotta go with real world experience on this one.

Okay, so you are saying you don't doubt the validity of his calculations, but they are wrong? You ought to be a politician.

I think he's trying to say that the calculations only explain part of the truth.

Frenchie send me an E-mail and I'll be glad to talk a bit more seriously about this whole speed thing.
Sincerely,
Marc

Man those are serious words Marc!!!

The entire system (boat, wind, sails, waves..etc) are a VERY dynamic system to say the least. Nothing stays the same for very long. Heck, just replication of a previous event is nearly impossible.

Simulation/modeling of other less dynamic situations is possible, but in those cases, there are much fewer variables and variations within those variables. That doesn't make them easy by any means, but... The quantity of randomly generated variables in sailing is well beyond the power of any computer or programmer.

To rephrase what someone else said, simulation/calculation can only get you in the ballpark. Successful designers work with that knowledge in mind. You design for what you want, but build in some "extra" just to make sure... rig for the lulls.

so that was way outside the initial post... I guess what I want to say is, show me the correlation or combination of, that will predict max hull speed on a boat that has two hulls with areas of displacement, areas of planing and areas of transitional movement. With all changing at the same time in random fashion.

Not saying it can't be done, just doubtful that it can be done accurately in the conditions we are speaking of.

Will R

Interesting thread, although it seems like it`s gone off the rails a bit. The fastest my beach cat has ever gone is 78 knots, or 90,06mph, or 145km/h, whatever you prefer.
It was on it`s trailer at the time, behind my truck.
I find it difficult to believe Frenchie that the fastest a Tornado has ever been timed over a 500m course was at around 22 knots, I know a Tornado is quicker than my 16ft
beach cat by a long way, so based on this info I can assume that the fastest my cat can go is about 18 knots.
Looking at the WSSC speed-sailing records I find that in 1977 Derk Thijs sailed a standard Windglider sailboard over the same timed course at an average speed of 19,1 knots.
Anyone who has ever seen a standard Windglider sailboard from that era will know without a doubt that a modern beach cat is capable of going faster than that - If you don`t
agree, bring your Windglider to the next cat regatta & prove your point in flat water on a broad reach. It won`t be pretty. If the Windglider wins, let me know & I`ll go back to sailing
standard one-design Windsurfers with soft sails & no footstraps.
You can take all the mathematical formulas you like & test in a laboratory all you like, the answers lie only down a 500m course in flat water with a stopwatch at either end.

Cheers
Steve

Dear Mary,

I like very much women who take time to time a walk on the "wild side"...and perfectly understand your instinctive reaction. You must be an hybrid of Geena Davis and Sharon Stone !

Well, my european temper just try to keep cool a simple sailor's debate...I'm owning a Formula 20 and practice since 1982. I'm an aero-hydrodynamicist and very found of speed.

I have seen many european SPEEDWEEKS during the last 20 years, you can check the records and clocking charts on speedsailing websites. There was NEVER such speeds recorded, even on bursts...and the WEYMOUTH place is a super spot for that purpose...That's where my relative suspicion over claimed 30 Kt+ on standard series cats built up in the history...

You know, the only cat to hit 28,14 kt over 500 m was called "Arcachon's District" and was a 440 lbs 25 footer with 300 sq.ft and pure floatplane-like amas...and she was just kissing water at speed on a less than 1 m wetted length...standard cats couldn't...that's WHY I'm SKEPTIC !!!

Politness seems the cornerstone of every debate between world citizens, even if action seems often necessary to overcome at times some "United Nations-like" mess.

I politely propose that a "Dragster Blast-Cat Challenge" will be put up at Texas City or anywhere else in the USA and that speeds will be rigourosly recorded here...that will end POLITELY the debate...why not gently launch iniatiatives like that...inviting Mitch Booth, Randy Smith, Yves Loday and Hagara ?

Friendly Yours,
a polite Frenchie

Finally, the

Frenchie, I compliment you on keeping your cool. I have enjoyed this thread, until now when the editor, feeling that the participants have been too polite, questions your authority to question others and disputes your well reasoned claims on the basis of what? her experiences? No, her other authoritative friends. I thought we were close to a new age in sailing, when objective analysis and understanding of physical laws would perevade. And I thought we were at a new era for catsailor.com when we could civilly disagree. I am deeply disappointed and discouraged, and feel compelled to speak in your behalf.

I am confused about Wouter's statement. Some years ago a similar thread was on the old forum. I maintained as most have on this one, that speeds well inexcess of 20kt were normally possible. Wouter replied that the top speed of a 20'beach cat would be around 20kts, so did Bill Roberts. Bill Roberts sailed 'round Texel at an avg. slightly in excess of 20kts, so I argued that he must have exceeded 20kts substantially at times. Then it was pointed out to me that it was under wave assisted conditions. So it would appear that a following sea might add 2kts. The top speed of a cat ought to be (ideally) on flat water, or across at least 3 waves (to get an meaningful average). I think most of us would like to know what the burst capabilities are, but the speed of dropping down one wave face, while great fun, is no real indicator of how fast the boat itself can go. Frenchie, I would like to have your email. Steve Blevins

I wasn't going to say any more on this thread, but now I have to tell you guys that I am NOT the editor or moderator or anything else on this forum or website. Please do not blame Rick for the transgressions of his wife, because he doesn't even want me posting on the forum -- probably because of the reaction you had, wrongly thinking I am involved with it somehow.

I am just a contributor like all the rest of you. And I am the one who has basically been accused of lying (either myself or Henry Rodriguez), so I just reacted perhaps too strongly. Sorry.

I give up. You're right. It is not possible for a catamaran to go over 22 knots. I checked the story in Catamaran Sailor Magazine (I AM the editor of that) for the year of that record Steeplechase, and Henry did indeed say that in portions of the race their GPS showed consistent speeds of 29 mph on a beam reach with FLAT water and consistent 20 mph wind. Obviously 29 mph must convert to 22 knots or less. Unfortunately, I don't know the conversion. Please excuse my stupidity.

Frenchie,

Wouters comments were in reply to my thread "speed!", I was actually more interested in the cat speed compared to wind speed, but asked about top speed out of curiosity.

The reason I asked the question is because I am considering putting a biplane rig on my cat. And it struck me that a biplane rig would only work well if the cat was able to sail faster than the wind as this would mean the apparent wind would be unlikely to result in one sail masking the other.

Indeed I think the fastest boat at Weymouth was a biplane rigged trifoiler.

Now that this thread has got so much attention from so many knowledgable people what do people think of biplane rigs on beach cats?