Foiler Design

Firstest

Yeah, Ian Ward was the first person in history to fly on just two foils in a singlehanded dinghy --no doubt about it. See http://www.monofoiler.com for pix of a lot of different monofoilers..
The bi-foiler concept that Ian pioneered has been taken to the next level by John and Garth Ilett who produced a race winning system in the Moth Class. That system was used by Rohan Veal to win the Australian Nationals and ,recently, the Moth Europeans.
No doubt the Aussies have done remarkable work in hydrofoils! In fact, one of the worlds great hydrofoil pioneers and his assistant told me three years ago that sailing on just two foils would be impossible. They forgot to tell Ian and the Ilett brothers-and Rohan Veal. Veal has done some pioneering work of his own in learning how to race a foiler. It appears that he developed the tactic of sailing the Moth foiler heeled to windward going upwind.
Ians work with the "unifoiler" concept will be interesting to follow-all very exciting stuff!
For two excellent articles by Ian Ward on monofoilers read the October and November issues of Seahorse magazine.

 

foil development history

Doug

I would be interested to chat to the foil pioneers that said "it could not be done" three years ago. It is now nearly five years since David lugg and myself solved the problem of using two deep running foils and nearly four years since the Seahorse article was written. I believe our work predated the moths using the same configuration by a season. I also understand that it was direct contact between David Lugg and Rohan Veal the lead to John Illet's involvement and John's development of the trailing arm automatic height control system. The trailing arm control on Rave may have predated John's work, can you clarify this.


Alan Smith
http://home.kooee.com.au/zach/hydrofoil.htm

 

History

Alan, time flys -it may have been four years ago-just when I was introducing my F3 that the comments were made to me by "them who shall remain nameless". The Rave wand system predates the Moth for sure; I remember having a long conversation(via e-mail) with John Ilett about the wand back in that time frame. I became intimately familiar with the Rave wand working with Dr. Bradfield as he converted one of my trimaran models to foils and then in the development of my rc foiler, the F3.
I'm using the wand system on my 16 footer and on a smaller boat both of which should be sailing by March.
But the wand system predates the Rave by some years since it was used on Philip Hansfords "Mayfly" long ago....
I've tried to keep monofoiler history straight on monofoiler.com and I have David Luggs boat down as the first monofoiler sailed by two people on just two foils. Now, whether that predates Ian Wards bi-foiler work you and he will have to tell me.If any changes have to be made to monofoiler.com to reflect history accurately I'll surely make them so help me out here.
The work done by all these guys has stunned many people and is no less than a revolution in sailing-one that I am glad to be part of in some small way and sure glad to see!!

 

Nope. Gotta go back to 1957. Dig those cotton sails!



Baker "Monitor"

Length of Hull 26 ft, 7.92 m.
Overall width 21 ft, 6,4 m
Sail Area 230 sqft, 21,37 m2
Weight hull approx. 800 lbs, 360kg
Flying height approx 2ft 6 inch, 0,76 m
Take-off speed approx 9.5 kn, 5 m/s
Take-off wind speed 13 kn, B5
Top speed 30.4 / 38 kn, 15 / 19 m/s
Number of crew 2
Automatic trim regulation
Rolling moment partly compensated by differential; adjustment of foil angles.
All foil incidence angles adjustable in flight.
Estimated price of production model USD 20.000 - (1957!)

Data taken from Research Reviews August 1957

 

Looks like a practical little thing that

 

Well, I made one back in the '80s. Its still sitting in my back yard, hope to get sailing it again some day, job changes and lack of workshop facility have some how got in the way. It can 'fly' but is hard to manouver for normal sailing. It is a slightly simpler concept than most of the moth boats, just a surface following foil at the front, which is intended to be lightly loaded, and a fully immersed foil at the back. Was intended to be used with trapeze wire but I found that too difficult.

I do agree the moth class has made remarkable progress in developing the two foil concept in recent years.

John

 

Monitor

Well, the Monitor is represented on monofoiler.com and is surely the first monofoiler(I think). But ,as a minor point, the Monitor is a boat designed from scratch as foiler not a dinghy like the Moth or 470 with added foils.
The Monitor was a pioneeing effort and had variable angle of incidence surface piercing foils using shroud tension to change the angle-allowng the boat to generate it's own righting moment-if I remember correctly. The type foil system used on the Monitor -though vastly simplified- was used on one of the first foiler Moths but the three point configuration has been deemed illegal in that class. The three point configuration is seen on multifoilers like the Rave and Hobie trifoiler that use fully submerged foils instead of surface piercing foils along with a surface sensing altitude control system that also serves to generate righting moment.The current generation of dinghy foilers leave righting moment up to the crew and use the foils just to generate lift.(with the exception that Rohan Veals pioneering racing tactics on a foiler Moth include deliberately heeling a high flying Moth to weather upwind-which adds substantially to the righting moment. Many people had assumed that you would want to fly as low as possible so as not to increase the heeling moment too much-Rohan's technique shows that more altitude can be used very effectively)
Mr. Perry, I'd love to hear more about your work!

 

Just joined the forum after seeing a link from the uk Moth mailing list. I've got one of the two foiling 14s that have been mentioned. We're using John Ilett's scaled up moth foils and sensor. We've only been out twice. The first time was in about 12-18kts, way too gusty to be sensible but we did some flying before pulling off a tiller extension. Our first reaction was like all the moth sailors; it's a really wierd experience, it goes very quiet and stangely smooth and you just keep accelerating.

The second time out, last Saturday was in no more than 9kts of wind. It was very frustrating, we'd get the kite up and keep getting lift but as soon as we were clear of the water I'd have to come in off the wire and we'd land again. We suspect that it is due to the fact that the centreboard gets smaller and just stalls so we just start going sideways as we get airborne.

Conclusions so far are that the foils work straight out of the box, thanks for John's (fastacraft) excellent engineering, also it is much easier than we expected. I'd heard from Luggy that the foiling 14 in perth was a bit tricky to control but we haven't found that yet. It may be that the automatic lift control on the centreboad helps. It also seems to be easier than the moth, from discussions with moth sailors, this could be because the foils are much further apart and a bit longer, so we've got better pitch stability and more time to react before the foils come out of the water.

We are planning on getting loads of photos and videos as soon as possible, everything is ready on that front, we just need the weather to be sensible!

some more photos of Alan Smith and Dave Lugg's foiling:
foiling 14

 

The Rave system was done well before my own wand system which is of course different as it is mounted on the bow. This senses not only altitude but attitude too.

Also I first met/spoke with Rohan some quite months after my brother Garths boat was first foiled. The was the first incarnation of this system with Rohans boat being the second as a straight out of the box foiler. So it is not possible that Rohan initiated any development.

There are now 12 moths sailing with this system with three more under contruction at the moment that will be sailing by Christmas.

 

14 Foils

Andy/John, can you share the I14 foil dimensions?
John, how does your wand system work to sense "attitude" as well as altitude?
You've sure done spectacular work in revolutionizing sailing!

 

Has anyone looked into canards for trimaran hulls. I would think they would work great for power boats.

Thanks

 

Hi Thomas,

The configuration with a stabilizer in the front is called “canard” (it means duck in French because ducks fly in this configuration)
You make a little mistake saying “conard” witch has an other meaning (something like an insult)

--
Gérard

 

Several companies already manufacture bow-mounted T-foils. These are commonly found on high speed catamarans. They're used both for motion control and for enhancing performance.

http://www.*****************/images/Copy_of_Frdfoil.jpg
(From Bugatti Yachts, http://www.*****************/BugattiYachts/Advanced_Hulls.htm)

 

foil design

Thanks for the picture.

Do to my consern about running aground I am loooking for something that is more at hull height rather than so far under the hull. I understand this would mot provide as much lift, but it would provide some, and I would think there would also be some increase in stablity.

Thanks

Thomas

 

Low ventilation struts

There has been lots of useful discussion of ways to avoid ventilation for surface piercing foils, which appears to be one of the most critical problems for sailing hydrofoils.

The miller sailboard configuration avoids this problem by minimising lifting forces on a single surface piercing strut angled upwind during sailing, and instead gaining sideways 'lift' from a fully submerged vertical foil (to oppose the sail).

An alternative approach would be to support the boat/board using non-lifting struts from fully submerged foils- the submerged foil would provide both vertical lift (to support the boat/board) and horizontal lift (to oppose the sail).

The strut(s) would have to have:
Minimal potential to ventilate the submerged foils.
Minimal drag.
Minimal lift. The submerged foil is intended to provide horizontal lift.
Finally, in order to be strong and stiff enough, it would have to be reasonably thick.

Is there a magical section that has these features? I would imagine that minimising lift from a section would help prevent ventilation, but have no hydrodynamic knowledge to support this idea.

I imagine that human powered hydrofoil craft, without the sideways forces required for sailing, utilise similar sections as struts to their load bearing foils.