From http://www.hydroptere.com/

the Hydroptère
Vue de Face
front cut
A few figures
Lenght...18 m
SPan...24,5 m
Mast height...27 m
Lenght of the lateral foils...6,5 m
Saffron height...3,6 m

Mass when taking off...6,5 tonnes (5-people crew)
Mass when navigating...7 tonnes ( 800 Kg of ballast wind)

Nitrogen pressure in the clipping ...160 bass

High Sail...165 m²
High Sail 1 ris...138,5 m²
High Sail 2 ris...11O m²
Génaker surface.....184 m²
Solent surface ...94 m²
Trinquette surface....49 m²


Minimum wind strenght necessary to take off...12 knots
Maximum speed...45 knots

http://www.hydroptere.com/

Apparently its done 39 knots across the english channel.

I'm counting the seconds down until wout comes in here and tells us how the angle of the alignment of the moons of jupiter will not allow this speed.

That was offset by Venus being in the third house and Pluto being downgraded to lump.

It was a gps spike!

39 knot average across the English Channel

Cool! Either way.

But can we adapt these V foil things and put them on a beach cat? I think that is what Dr. Sam Bradfield(?) was trying to do with a Hobie 18 several years back, but I haven't heard anything about that for 3 years.

I think Sam Bradfield went on and implemented his ideas in a larger trimaran foiler, SCAT. I remember reading about the boat in som older "Multihulls magazine", but have not heard much about the project lately.

A quick web search gave these links:
http://members.aol.com/HYDROSAIL/
http://www.multihulltechnologies.com/scat.htm
http://www.ronbarrett.com/Scat.htm



The Hydroptere is just stunning, when it dont break down..

I think the nitrogen charged shock absorbers (which probably allow adjustment of the angle of the foil too) are new and something they've done to overcome some system failures.

IIRC the time they tried going across the atlantic, the foil didn't shear off by itself. They claimed that they hit something in the water with it.

But it has failed by itself before, and there used to be video of it crashing and burning when the foil decided to go byebye.

That is in this video Historique half way in, "December 1995"

That's a great video! At times it looks like maybe they need more lift off the low side ama/foil. Sometimes it looks like a normal Formula 60 tri flying two hulls, with the low ama in the water. It seems they could put more foils, or larger foils on the ama's, and get the floats out of the water sooner and keep them out longer. Of course that would lead to more drag and ultimately a bit slower, but perhaps more in control.

The Hobie 18 project I saw pictures of once had two v type foils added at the forward crossbar, I never saw the rudders and I never saw it foiling, just a picture on land. It seems to me if you put some V type foils at the front of a light, fast cat (A cat?) and some T foils on the rudders, you could foil it easily, much easier and with better balance than that 18 foot skiff we saw.

I like the looks of the V type foils much better than that big wide T foil. The T looks like a crab pot or sea weed catcher.

Just one correction: Hydroptére features one adjustable Bruce foil (= canted asymetric daggerboard) in each ama and a "T" foil in the rudder. There is no "V" foil.

Dave Carlson did just that on his A and it flew quite well. Saw his boat even at Spring fever 2002.

And I hate to say it again guys but bruce foils are the way to go.

Did any notice that baby Hydropthere in the video. The one that was singlehanded. Looks much more like a sailboat then those waverider things. No wants or bungeer control. The whole thing is selfregulating.

And looks more stable then the flying moths even though in the beginning the skipper is struggling to keep it level.

Cool.

Wouter

Luiz, by V foil that is what I meant, there is no good way to describe it with keyboard symbols though...maybe I should have used the \o-O-o/ for the symbol? But I meant what is on that thing up above, I guess it's a Bruce foil.

BTW, the Hobie 18 I was refering to had two foils that looked like an upside down A or a V with a cross foil, like a V shaped ladder where the rungs were also foils. One was mounted on each hull just forward of the main beam and they could pivot up for launching and trailering.

"And looks more stable then the flying moths even though in the beginning the skipper is struggling to keep it level"

Sailing cats and having once tried to sail a moth that is an comparison without any relevance at all.

Sailing a moth at all is a demonstration of incredible balance compared to sailing a beachcat. The behaviour of the prototype seem in the light of that to be very very unstable compared to a normal cat. On the other hand the foiling moths seem more or less as stable as normal moths.

A bungee more or less would not scare me. The possibility to have force both downwards and upwards appeals as well as the possibility to regulate riding height more precisely with sensors than with a "stable" system.

What is your base for saying "bruce foils are the way to go?" Seems to me as a mere opinion, what is your line of reasoning?


//P

Far simpler to produce and engineer.

This system is fully selfsteering. In effect the setup can be as simple as putting your daggerboard cases under an inward angle and using the same daggerboards as before. This is especially welcome on beach cats. Only additional modification is a T-foil rudder system when you want to go full foiling. If you are only intended to do partial foiling then you can continue to use non-T-foil kick-up rudders.

When longer daggerboards are used then the height of foiling can actually be set by pushing the boards further down or pulling them slightly up. Again, no moving parts apart from the boards itself sliding up and down. In effect this is an inmensely simply system to produce and maintain.

When speed increases then the boat is lifted higher above the water surface, thus reducing the wetted area of the foiling board. The excess area is moved out of the water into the much less dense air. This means that the angle of attack of the board is also a selfregulating system it will pretty much always operate at an optimal angle of attack. In T- shaped foil systems the angle of attack must be changed actively (want system) to stabilize the boat in height. This means that when the speed is increased the T-foil will operate at less efficient angle of attacks. Bruce foils do have added drag of the spray they throw up but it is not certain that is less efficient then an T-foil operating at a sub optimal angle of attack.

The bruce foil system itself will react to waves and such without any additional gear.

Bruce foiling is more efficient in conditions that don't allow full flight. This because the foil itself also acts as the daggerboard, resisting sideways slip. It may well be engineered as a pure partically foiling system, where always less then 100 % of the weight is carried by the foils. This helps increase the top speed when there is sufficient wind and maintains sufficient light weather performance.

It is my personal opinion that full foiling is still too much like a single gear race car to be a winner over a full range of conditions like we see in windward-leeward bouy racing.

But I'm happy to be proven wrong by anybody. So guys who is up to building a full foiling catamaran under a fixed rule system and race it around the cans in a few different wind strengths.

The bruce foiling guys has already done that See picture.





Wouter

Hi Wouter.
Who are these guys? The lifting foil appears to be nearly horizontal, right? At speed the lee foil isn't doing a lot of lifting , according to your accompanying pic. Why not?

The Little America's Cup C-class Cogito has been actually lifted clear of the surface by their Bruce foils.... then they become badly frightened and sheet out, I believe.
Fortunately our smaller foil boats are less fragile (and less expensive) so we don't care, and continue on!
So what is next from Europe? Where sailing innovation occurs.

John de Vries and his crew (looks like Sacha de Boer in this pic)

Boat was build by Reg White of White formula boats.

The boat is called a John-de-Vries special or White formula special.





Ohh no, it wouldn't be more then angle at 45 degrees. I think it is angled less even. It is not intended for full foiling. Just to partially lift the hulls and reduce wetted surface area. Another benefit that was quoted (by another guy experimenting with a similar setup) was that it stabilizes the platform in fore and aft direction. The boat pitches less.





How do you figure that. Can't see the leeward foils nor do we know how they are angled (rotated) in the horizontal plane.





They used curved daggerboards don't they ? Then they could have solved the issue by raising these a little.




And these tinkers will always have my outmost respect.


Have you seen the video were an ORMA 60 tri is lifted out of the water by its angled foils ?

It happened during a speed trail between boats and boards of all makes. The ORMA boys won that contest with 33 knots of speed. But the skipper said during the interview that they were working hard to keep the boat going through the water and not fly above it. The last looks spectacular but was found to be actually slower then sailing partly through the water.

I'll see if I can find the clip again.





Well, we still have the planing cat (ORMA 60) by Yves Pallier. But we shouldn't forget about Australia. 50 knot record attempt and the foiling moths. There is something brewing in the A-cat scene I think. They are looking for a new development since the flyer of the late 90's. There is some more beach cat consideration going on with respect to T-foil rudders. Also we have the development of a cross between spinnaker and kite down under in Aus. Carbon boat fashion in Europe has stopped somewhat, kevlar is coming in season.

Wouter

Hold on to your seat guys because here you get 15 minutes worth of French speed sailor. Everything goes, kite boards, windsurfers, Orange 2, ORMA 60, open 60, open 70 and what else kind of contraption uncle Pierre build in his garage.

Rules, cover a 5 or 8 mile stretch water in the fastest time possible. Ergo we are talking sustained average speeds of 30 knots here and they have to keep it up for at least 10 minutes.

This is the high res file. 70 megs big, so download to disk before playing.

http://www.grandprixpetitnavire.com/defi/video/DPN2005SSZIK768.wmv

Also note the windward canted rig of those ORMA 60's.



There are also low res versions available, as well as other vids of same event, at this page :

http://www.grandprixpetitnavire.com/defi/video.php


The event is called Le grand Prix Petit Navire

http://www.grandprixpetitnavire.com/

The event was won by gitana 10 (If I understand that French right) with 32,70 knots.

Enjoy !

Wouter