Sunday, December 28, 2008

turning on HUNDREDS of people

I don't understand. I offered Bora the chance of a life time chance to make a real difference in building interest in the Moth -and foiling-while still getting your chance to try to ridicule me in front of HUNDREDS of people!!

I find it incredible that he would turn it down.

In early March(I think) Tinho Dornellas will have his annual Windsurfing Midwinters at his location here at Kelly Park on the Banana River. I suggested he come here then and put on a demonstration for the hundreds of people( many kids) and I'll sail the Moth when he's done.

When here he can go visit, Mickey Mouse(only 50 miles), and the space center as well as having the great pleasure of turning on HUNDREDS of people at one location. And make a great contribution to foiling in the US as well.


Well Bora, are you in? You come down here and demonstrate the boat for the people and I'll still show you how to foil it!

Friday, December 26, 2008

Bethwaite foiling 49er

The fact that Bethwaite is developing a BI-FOILER 49er is revealed in the Jan 2009 Seahorse with a picture, where you can clearly see the sliding bench seat.

Bethwaite is confident that his team is almost there, which is, of course a revolution.


Shown underway as well is the notorius outboard powered 49er hull using three foils with a trailing edge wand on the forward foil.

Soon, when they learn the ways of foiling and grow in their knowledge of my patents, they too will want strike me down with all their hatred, and their journey towards the dark side will be complete.

Thursday, December 18, 2008

the Master of Multifoiler Design is back!

18' Multifoiler from Dr. Sam Bradfield, the Master of Multifoiler Design is back!

This time his boat has many new features including a new automatic altitude control system developed by the Hydrosail Team. Here are the specs:


- 18’ racing trimaran
- highly-maneuverable, except when it is not
- light and lean for speed with large flight window
- T-foils with automatic flight control systems, that are manually controlled
- Park benches
- High windage Mirabaud style pods hulls
- Jump-o-matic version will be available

The two main foils roughly split the load-which is way more than the weight of the boat.

This is a new project with technology only hinted at in a few other foiler prototypes. Bradfield has held the world speed record in the B class with a foiler of his own design and comes second only to me when it comes to foiler development experience.

He is fully capable of producing an astonishingly high performance foiler.

I've always believed a bi-foil monofoiler was better than a Rave in light to moderate air-but this new boat(as I understand it) will be very light with no wands. Based on my numbers, it will take off in the same wind a Moth will.

And will have the same advantage the Rave did in winds over 20.

Bradfield is pioneering a differential altitude control system for the Osprey that will be extraordinary....

I am sure that this will be a great commercial success, just like the rave, and the Hobi trifoiler and the Kona kat.

Thursday, December 11, 2008

Foiling crediblity

I see an attitude lot from some Mothies: as far as foiling goes some of you think you're the only game in town.

That is no longer true since there are NON MOTH bi-foil monofoilers and multifoilers in development or being sailed all over the world. The attitude that you know all there is to know or will ever be known about foiling is bullshit-get over it!

My experience sailing 2 different monofoilers, 1 multifoiler is far more credible than a couple of years racing a moth.


Tuesday, December 9, 2008

forget planing, the foiling sportsboat

The next breakthru is not planing upwind-it is flying a sportboat upwind.....
30' LOA sportboat on foils:

My personal opinion is that chasing an upwind planing keelboat is a lot of effort to go a little faster-seems that a bi-foiler sportboat would be a better choice-a lot of effort to go a lot faster upwind and offwind.

BUT you should put some numbers on paper and see what it would take.
Bethwaites SCP/Total weight ratio predicts that a boat with a ratio over 30% will plane upwind. It goes like this:

RM(righting moment) divided by the distance between the CE(center of effort) and the CLP(CLR)(center of lateral pressure(resistance) equals SCP.

SCP divided by total weight is a percentage. It will work with metric or US measure-just use consistent units.

You can play with this to see what combination of SA,weight,RM will actually have a chance of working.

This also works(with other indicators) to predict "foilability" but was designed to predict upwind planing.

Another problem with planing monohull keelboats is the relatively wide hull that is generally thought to be requied. With a potential keelboat foiler you go with a 10/1 L/B ratio to start with(MAX width) so weight is already reduced a lot.

You can see below that its a bit tough to get good numbers.......


Numbers for a foiler-for a planing hull weight would have to increase but there is enough margin for that, I think:

---LOA 24'
---LWL 24'
---Beam 18.6' (overall, incl. racks)2.4' at waterline
---Draft 6.5' keel,rudder retractable
---Sail Area 586sq.ft. upwind and downwind (planing boat would need big spin)
---Boat weight,incl. rig and ballast-1100lb.
---Ballast 490lb. (110° canting keel)110° canting keel wouldn't work on a planing hull so keel might have to be deeper @ 55-60° cant.
---Displacement (incl crew)-1420lb.
SCP/Total weight=42%


And before you say that it doesn't fit the rules. So what? Rules are meant to be changed when they hold back developement with artificial restrictions.

It's only a model

The tips presented here will be those that I know work and that have been extensively tested on the water and in testing of two F3 hydrofoils side by side and Dr. Bradfields modified Flyer hydrofoil.

These foilers use fully submerged foils as opposed to surface piercing foils and the major advantage (in rc models) seems to be the fact that they generate their own stability. The more wind pressure ;the more stable the boat is.The F3 has been sailed in winds well over 20mph and the Flyer? in over 30.Fairly accurately ESTIMATED boat speed of the F3 in 16-22mph of wind=20mph.In 5-7mph of wind boat speed was ESTIMATED at 10-12 mph.

No other multihull available anywhere has this kind of automatic hands off stability system. On "normal" multihulls (F48,mini 40 and multiONE) immense concentration is needed just to keep the boat upright in medium to heavy air. The Bradfield type foiler ,like the F3, virtualy eliminates all those hassles and allows the skipper to just enjoy the speed without the capsize worry. A boat like this can still be capsized if it is set up incorrectly(set up should be a one time thing) or if too much sail is used for the conditions but I can supply a sail area guide that will eliminate that problem. And if you use the same rig as the F3, Flyer or X3 you won't need multiple rigs since those rigs reef thru out the windrange .

Another thing:the F3 type foiler can carry its "A"(unreefed) rig in higher winds than any other multihull because of the automatic stabitiy system but at some point sail will have to be reduced.I have a guide to knowing exactly when...

Foiling occurs on the F3 in 5-6mph of wind.Most of this is based on the F3; some ideas relating to the X3 retractable foiler are presented though that boat has not been tested yet.

Design Facts:

1) the quarter chord of the two main foils should be located so that they carry 80% of the weight and the rudder t-foil carries 20% of the weight. This generally results in a rig further forward than is "normal" on an rc multihull because the quarter chord of the vertical fin is, by necessity, in the same place. That is also the location of the CLR of the boat for balance(weather vs. lee helm)considerations.

2)A single cross arm is all that is necessary but it must be exceptionally stiff torsionally.

3) the center line of the outboard foils is ideally located about 1.07 times hull length apart centered on the main hull athwhartship. In the F48 class this is not possible and results in the hydrofoil for the f48 having to do slightly more work than that for the F3. In the multiONE Class while loa is one meter BOA is 48". The wider the boat the less the loading of the foils.In many tests the location of the vertical fins so far outboard has not affected tacking ability in the least; a foiler on foils will tack at least as fast as a fast monohull...

4) The automatic altitude control system depends on two"wands"which are straight or curved thin carbon tubes or rods that drag in the water. Before foiling the water pressure pushes them aft forcing the flap on the hydrofoil down to the high lift position. A spring or shock cord is attached to the wand so that as the boat rises the bottom of the wand moves forward neutralizing the flap on the foil or even creating negative lift.This is how the boat develops its own righting moment: the diferential lift required to create and maintain the exact right amount of lift AND righting moment is created by the movement of the wands connected to flaps on the two main forward hydrofoils: it is 100% automatic requiring no radio control!

5) The F3 will foil in very light air but because of the automatic altitude control system there is a lot of drag when not on foils.The "wands" can be removed in light air drmatically reducing drag since the flap is not then being automatically pushed into a high lift position. Or this type of foiler can be designed to use retractable foils which has not been tested in the water but since the foil system is identical and the rotation system so simple it should work but as yet this remains untested. F3 type foilers have been tested with no wands for light air.F3 One Design races would not be held in less than foiling conditions but F48,mini 40 & multiONE races will be held in very light conditions so it could pay if you consider an F48 size foiler to go ahead with a retractable system.

6) the main foils are installed as previously mentioned with a +2.5 degree angle of incidence relative to the flight waterline. The rear t-foil is set at 0 degrees.

Mainfoil area should be determined as follows:For a weight of 8 pounds the two main foils will lift 80% or 6.4lbs.; 3.2 pounds each. They require an area of 17 sq.inches to do that or .188lbs per square inch. Note that this is just to make calculation simple and does not reflect the ACTUAL loading of each foil since ,in developing righting moment, they are much more highly loaded. A Foiler should be designed with approximate 200 sq. in. of sail area per pound of weight. Of that sail area the MAIN foils should carry 49 of sail area per of foil area.(Divide Sail Area by 49 to get mainfoil area=both foils; then divide in half for the area of one foil.Try to achieve the loading and sailarea for the foils and displacement of the boat.

In summary:

A).188lb.s per sq. inch loading of the main foils only -just using 80% of the boats weight.

B) 49 sq. in. of sail area per sq. in of main foil area. This can be varied a little and is applicable from a multiONE to a two meter.C) this will produce a boat that will take off in light air.(5-6mph)
The rudder t-foil should be 50% of the total of both mainfoils or slightly less.(Equivalent to one main foil works well)

7) The amas on a foiler the size of the F3(LOA 56") are 36" LOA with an 18/1 beam to length ratio and total buoyancy of 7 pounds. They are not capable of flying the main hull and do not need to be.Amas for an F48,mini 40 should be about the same size due to the proportionately narrower beam. For the multiONE they can be directly scaled down.

8)On the F3 the foils fit in trunks in each ama and that requires that not only the tube comprising the cross arm be exceptionally stiff torsionally but the joint between the ama and the cross arm needs to be exceptionally stiff. On the retractable design (untested as yet) the foils are mounted within carbon tubes that fit within bearings into another carbon tube allowing the whole foil/altitude control mechanism to rotate.Viewed from forward the foils rotate like airplane propellers toward the main hull untill they are vertical. The lower portion of each foil then acts as lateral resistance for the boat in light air.

The mounting of the rotational part of the the foil system allows the foil to have a zero degree angle of incidence when the foil is vertical. While I haven't tested this on the water yet I'm confident that it will work since it is so simple.The one downside may be the area of foil still in the water. The idea is to eliminate any need for a daggerboard when the foils are retracted by using the foils themselves as lateral resistance when they aren't being used for lift.


You don't need a retractable system to enjoy sailing a foiler as described above; it takes off in such light air that you'll be foiling most of the time anyway. The only benefit to a retractable system is in light air or transitional foiling conditions(under 6mph wind) and the only benefit is in a class like the F48,mini 40 or multiONE in light air racing.

For anyone interested I can answer any questions and provide sketches of the wand system but the basics are here-you can design a foiler with the information provided above....

Oh, and it's only a model

Sunday, November 16, 2008

High Performance Beach Cat Killer Tri Under 20', -capable of flying the main hull

Why don't we see a tri like this anywhere? Seems like if the technology that has been applied to Orma Tri's, Banque Populaire,the DOG tri and Stealth beach cats was applied to,say, an 18 foot tri- cats would no longer rule 20' and under. Why isn't someone doing it-or are they?

What’s the point?
More speed. You would have nearly twice the righting moment and 1.7 times the SA for any given length if you went all out. Should be faster in almost any condition than a cat of the same length.

Came up with this a couple of years ago and thought I'd mention the concept since I can't afford to patent it-and because I think it has a great deal of potential.

I was impressed by Yves Parlier's l'hydraplaneur which for those that don't know is an Open 60 multi with a difference: it is a cat with two stepped planing hulls looking somewhat like seaplane hulls.In the original article in Seahorse the boat was supposed to have some form of "variable geometry" to mitigate the negative effects of the steps at low speed. The article said the area of highest drag for the boat was between about eight knots and twenty knots with drag above twenty dropping to a fraction of the drag of a "normal" displacement multihull at that speed. In sailing against the ORMA tri's the boat showed flashes of speed but was basically crushed in the two races I'm familiar with.
Since I've designed and sailed numerous multihulls both full size and radio control the idea kind of interested me but I wanted a way to eliminate problems with the step at low and moderate speeds.What I came up with is this:

I envisioned a trimaran test boat 18' LOA with an 18' beam. The main hull would have a hydrofoil on the daggerboard and one on the rudder. But the amas are the key to this concept: they ROTATE! At slow-moderate speeds the ama is an 18-20/1 displacement hull but as the boat approaches a still to be determined "rotational" speed the windward ama is rotated 180°; the boat then tacks and the other ama is rotated .The bottom of the rotated ama is a stepped hull designed to reduce drag(up to 80% compared to a displacement high L/B hull) above a certain speed. The two foils are designed both to lift the mainhull early AND to possibly add to RM as max speed is approached.They also function to assure pitch stability given the massive sail carrying power of the boat.There is a lot of room for experimentation with the foils since it is possible that their area could be kept quite small. The test boat would be designed to utilize two crew trapezing off the windward ama.

I've built a small balsa model just to work out the geometry and it works out quite nicely.It is a weird looking hull with the displacement hull deck the bottom of the stepped planing hull! Next thing would be a fully functional rc model but that is quite a ways off. I think it is a beachcat killer with real high potential speed.Great applications on larger versions as well. But right now it's just an idea.... So what do you think?

Rotation would be accomplished from the cockpit using a belt drive crank(wheel) with a separate actuator for a carbon pin. The boat would be engineered by a naval architect and a smaller test version would be built first. The foiler I am building now will have removable amas(to replace the pods) so that rotation can be experimented with fairly soon-6mos to a year from now, I hope). Not just rotation but also the variable angle of attack of the planing surface using two foils for pitch control.
I don't think a small trimaran has been done yet that incorporates the power this thing has-except maybe Exploder or Reynolds early tri. The boat is designed to fly the main hull(like an ORMA 60) from a boat speed of 5 knots and up with the foils used PRIMARILY for pitch control.
A few more notes:

1)The rotation is only done at the as yet to be determined crossover point-not necessarily when the main hull flys(which will be at about 5-6knots boat speed max.) but when the planing hulls will work optimally.

2) Rotation will be manual and very simple and quick-it would not be frequently done at most venues.

3) Shrouds ,if any, will go outboard almost max(or where the NA says). I would like to look very carefuly at an unstayed highspeed rig like a Moth type(w/o the stays) as well as a wing rig for a speed version depending on weight. My realistic guestimate is that a partially stayed rig will be required.

4) Estimated upwind SA for this boat is 380sq.ft. compared to 227 for the Hobie Tiger. The Max RM for the 18 tri would be 10512 vs 5197 for the tiger-over TWICE the Hobie RM for the 18.
This is based on two crew of 160lb. each on trapezes with the 18 just flying the main hull and the cat just flying the windward hull.

5) The 18 would have 2lb/sq.ft. sail loading vs 3.15 for the Tiger.

6) The Hobie weighs 397 lb. and is fiberglass/foam sandwich and this boat would be 100% carbon foam/honeycomb and a very rough estimate of weight would be all up at 447lb.

7)The boat could probably be "toned down" substantially and still beat most beach cats. The idea here is to illustrate what is possible with the trimaran configuration. One of the central themes of the 18 are the small hydrofoils on the daggerboard and rudder-FOR PITCH CONTROL ONLY. This,and the fact that the center of buoyancy moves forward when the ama's are planing will give the boat extraordinary resistance to pitchpoling.

8) The concept allows substantially smaller ama's and lighter all up weight than would be required without the foils and planing hulls.

Thursday, November 13, 2008

Dancing me

Ok I have just one a new sponsorship deal with eco, and we have produced a new promo video and you can see it here.

Friday, October 31, 2008

R Class foiler-the boat has foiled!

R Class foiler-the boat has foiled! Here are some numbers:

Hull weight 63lb(29kg) plus a min. of 20lb(9.1kg) for rig and foils(probably not possible at this weight)=83lb ready to sail(nice if you can do it!)

Sail Area upwind: 140 sq.ft.(13sq.m)

Hull beam at wl(ESTIMATE) 3'(.9m)results in a L/B ratio of 4.33/1

crew ESTIMATE=320lb.(145.5kg)

sailing weight=403lb(183.2kg)



This ratio would allow the boat to foil upwind but in marginal conditions /light air it probably would foil after the Moth,RS600FF,M4 and Foiling 18. To bring it to the 2.558 number of the Moth either SA would have to be increased to 158sq.ft(14.7 sq.m) or the weight would have to be reduced to 358lb.(162.7kg)-leaving a 275lb.(125kg) crew.

A probable negative factor that would suggest lowering the W/SA number further is the sloop rig
Another negative factor suggesting a lowering of the number even further is the relatively wide hull at the waterline(compared to the ideal).

This boat could foil well downwind even in light air-in heavy air downwind it would need a smaller much flatter spin.

It could foil upwind in all conditions a Moth with a 180lb crew could as is. But light air /marginal conditions performance would be improved if the negative factors above are addressed by less weight and/or more upwind SA.

If only it had pods, a sliding seat, manual control and dual midship wands.


Monday, October 20, 2008

crime against humanity

There is a rumor on the blogosphere that a 16' foiler, described as a "Monster Moth" by Phil S. exists and I don't have any details.

It is a crime against humanity to keep the fantastic development work he is doing to himself. Please-for the sake of all thats good and holy-please can someone ante up with the story and ideas! The only other alternative will be to send the foil police to deal with the situation.

Ok, perhaps I'm being too "demanding"-yeah, thats it. So how about posting the pictures and info one week from tomorrow? Is that ok? Thanks.

Wednesday, October 8, 2008

Kiting is kiting-sailing is not kiting-kiting is not sailing.

The magical 50 knots barrier fell as the outright sailing speed record fell twice in 24 hours at the L├╝deritz Speed Challenge over the weekend, with French kitesurfer Alexandre CAIZERGUES recording the fastest speed of all at 50.57 knots, subject to ratification by the World Sailing Speed Record Council (WSSRC). -

If a kiteboard is a boat then so is a waterski-absolutely ridiculous! A "boat" has to support it's load with buoyant lift at rest. But nothing can take away the kite guys accomplishment-so far(if ratified) it appears they hit 50 first-congratulations. But it is NOT a sailboat record-it is a kiteboard record.
And a kite is not a SAIL-it is a kite! In the same way an airplane is not a helicopter!

A kite can be moved independently of the"craft" it is powering to increase apparent wind enhancing power. A kite produces much more vertical lift than a sail. There is no "put-down" of kites or kiteboards in what I'm saying: it is a recognition that these two forms of harnessing wind power ARE different and should not be confused with each other in my humble opinion.

A kiteboard-carries one person only when moving -requires wind close to or higher than its top speed.
hydroptere-carries 11,000 lb of carbon + 8 people at 52knots in wind significantly less than its top speed.And it carries the same load at zero knots!

So I sent of an email and got this interesting reply from John Reed:
Dear Doug,

The categories which can make attempts on sailing speed records are decided
by ISAF.The WSSR has no responsibility to decide whether kites can claim
the outright record.


John Reed
Secretary to the WSSR Council
Guess I have to raise hell with ISAF. Right.... time for another email.

"I'm curious why ISAF considers kiteboarding to be "sailing" ? I think what the kiteboarders have done is phenominal but how can it be placed in the same category as a sailboat speed record?
No way is a kite a "sail"; no way is a kiteboard a boat.
So what is the rationale?
Sail Fast,Doug Lord"

If you have a board that is not a boat and a kite that is not a sail and yet you want to be able to claim a "sailing" speed record?! Listen, what kites have done is tremendous-but they are not "sailboats" and do not deserve a "sailing" record!!

Kiting is kiting-sailing is not kiting-kiting is not sailing. End of message.

Sunday, October 5, 2008

They REALLY don't know what they're talking about!!

The Bradfield planing wand has been around 8 years longer than the bow wand( which was copied from the Bradfield system) and can be adjustable-with the ratio of wand movement to flap movement completely adjustable with variations of the system including a wand clutch, adjustable bungee tension AND adjustable bungee responce.

Also, "cam" like adjustment set ups that allow variable RATES of flap movement for a given wand movement-and more-all developed by the Bradfield team years ago. And things like simultaneous fore and aft flap movement with 100% mixing adjustability, manual/wand instant switchback, manual only fore and aft systems,athwhartship angled midship wand pivot axis are being developed now(among other very interesting technical tidbits you will hear about in a while).

1) from seahugger mode to flap neutral the wand tip moves 62.5% of its max travel
2) from flap neutral to max flap up the wand moves 37.5% of its max travel

That gives much finer flap control from 10 degress flap down to 2.5 degrees flap up with much quicker reaction above 2.5 degrees up-something that is required on the Rave since the foil pulls down as well as up and is symetrical set with a 2.5 degree positive angle of incidence to the static(design) waterline.

So, you see, it pays to think(or at least check out the facts rather than guess) before you speak........

And,oh yes: a high priority on jumping with 100% successful re-entry.

Thursday, September 11, 2008

the ultimate kickass 2 person boat

Many have tried and are trying to convert existing two person dinghies to foilers but have you ever wondered what a two person foiler designed from scratch as a replacement for,say, the 49er might look like?

Here ya go:
LOA= 18'(5.49m)-no gantry
Hull Beam@ wl=1.6'(.49m)
Beam OA= 6'(1.8m-includes very small buoyancy pods)
Allup boat weight=154lb(70kg)
Nominal Crew Weight=320lb(145.5kg)(twin trapezes)
Sailing weight=474lb(215.5kg)
Sail Area=185 sq.ft(17.2sq.m)(main only-reefable rig)
W/SA=2.56(equal to or better than Moth,same vicinity as M4,I14(Lugg),Foiling 18)
SCP/total weight= 45%
SA/ws hullborne and foil borne greater than or equal to Moth
Retractable foils

Approx 50% of the hull/deck area of a 49er-less material-less cost
Approx 122lb(55.5 kg) less weight than 49er-less material-less cost
Approx. 44sq.ft less SA than 49er upwind. No Spin(light air code zero?)

---- With Manual controls and a retractable, sel-frighting K-Bulb, This boat could be MUCH faster than a 49er if carefully designed and engineered. And cost less.

Wednesday, September 10, 2008

The case for the midship wand

A midships wand is definitely better than a bow wand in flat water because it can be significantly lighter if the Bradfield system is followed.

In chop with a forward wand there is a delay between wand activation and the foil being where the wand was when activated of around a quarter second at upwind speeds in addition to wand response(bungy) lag. This intereferes with the ability of the forward wand to average it's inputs.

The midship wand has only bungy lag and therefore has a quicker and more reliable response to begining to average wand input resulting in a steady altitude and less of a likelyhood of dramatic flyouts from waves. This can be seen on the Rave video in the rapid movement of the wand which is noticeably more than on a Moth in similar conditions as best I can tell.

This is very important: Because the forward wand's center of lift(drag) is significantly displaced from the boats center of lift when flying there is another element added to the forward wand response and that is pitch coupling. This can add or subtract from the wands response-when it adds the boat flys out of a wave. That happens much less frequently with fewer consequences on a boat equipped with a midship wand where there is NO PITCH COUPLING whatsoever.

So the combination of the midship wand developing an averaging response quicker than does a forward wand and the pitch coupling common only with a forward wand explains very well the observed responses of both boats and seems to suggest that a well designed planing wand mounted midships might be an improvement on a monofoiler in every conditon.

At 22 knots there is no 'anticipatory' or 'reactionary' wand-just an averaging system with fairly rapid wand movement on a Bradfield system.

The bow wand would be subject to unanticipated moves due to pitch coupling as mentioned earlier. I'd bet that the midship wand would be -by far-best in these conditions.

The question about foil spray is one of the best yet. On the Bradfield system the wand is next to- not in line with -the foil and is not affected by the foil "spray" in any way. But in applying the Bradfield system to a bi-foiler the wand will need to be close to the center line and the foil wake and/or spray may or may not have some effect.

The Japanese Mothies are experimenting with an in line trailing wand system similar to the ones used for many years in human powered foilers(very successfuly). That type of wand does not have the power of a Bradfield type and yet has worked very well despite being located behind the vertical fin.I'd imagine that the Bradfield type would work well-I'll know before too long on my boat. It would be interesting to see three equal Moths rigged with the standard ,Bradfield type and Japanese type.

The problem with the bow wand seems to be that it can produce movements of the flap unrelated to the averaging of the wand.Depending on whether it adds to or subtracts from flap movement the average wand movement can result in unpredictable and sudden big movements of the flap.(Probably exacerbated with flexible wands)

This kind of pitch coupling can't occur in the Bradfield system because the wand makes contact with the water at the center of lift of the boat so there is no pitch coupling at all.

Unless the wavelength is so great that the boat contours the averaging occurs when the boat platforms and results in rapid wand movement(several times per second) while the boats altitude remains the same. In wave conditions where the boat is platforming the wand reacts multiple times per second and the forward wand anticipates nothing-in fact there is some reason to believe that in those conditions the separation between the center of lift of the wand and center of lift of the boat is not a positive thing at all-contributing to erratic behaviour. Flexible wands would tend to agravate the problem-both in averaging and with pitch coupling. Depending on whether the wand is a planing wand or not, conditions can make the ride feel like a bumpy road in short steep chop.

One thing all this recent wand study has done is reinforce 100 times over the fact that a manual system that mixes main foil control with rudder foil control will be superior in racing. Wand movement at multiple times per second reduced to virtually no movement! When the wand is averaging it is essentilly creating major changes in the lift coeficient of the foil rapidly and for no net change in altitude. This is a drag producing machine!

Manual control will be fairly hard to learn to race well but the potential savings are much greater that I thought just a few weeks ago.

Monday, September 8, 2008

You can't handle the truth

So every day I have some idiot telling me "pics or it didn't happen" or "you have never foiled". Well enough is enough. Just because I have never been seen foiling doesn't mean I haven't done it and here is the proof.

Why haven't I shown this before? Well the photo is out of focus, and blurry, and who wants to see an out of focus blurry picture?


So now that people can't call me up on the 100% proven part, what will they say now?

Foilers for big guys

Here is a pix of David Luggs I14 being sailed on two foils but using manual altitude control instead of a wand:

If you go to and look under John Ilett in the gallery you'll find more pix of 14's on foils using Johns wand system for altitude control. There is absolutely no reason why larger monofoilers can't foil and foil very quickly esp. if the foil loading, SA and RM are paid attention to. Numerous people all over the world are experimenting with and actually sailing larger two foil monofoilers.But the one unassailable fact is that the Moth has led the way in developing effective monofoiers and ,in particular, the two foil hydrofoil systems. Before that, for decades, foilers always had three foils.I'm 100% confident that bi-foil technology can be applied to much larger boats including such boats as the "Maxi Skiff's" conceived of by Julian Bethwaite and Sean Langman.

To say that larger boats can't foil upwind is just plain wrong. From an article by David Lugg in the May 2002 issue of Australian Sailng:"The first compromise was to reduce the foil size so that the hull did not leave the water at upwind speeds. Early experiments with larger foils HAD THE BOAT FOILBORNE UPWIND WITH EXCELLENT SPEED but greatly reduced pointing ability." That was 2001!!! And using a manual altitude control system! All this before anybody knew the techniques that would be developed by Rohan to fly fast upwind. Imagine if the class had not banned full flying hydrofoils!

There are some guys that have relatively recently used modern Ilett foils on 14's in Switzerland and I don't know their results yet.

But it is nuts to say that larger, heavier boats can't foil upwind! If you want to talk "boats" instead of just monofoilers I've sailed a Rave multifoiler upwind in 12-15 touching down for a split second while tacking. And I'm heavy! As to monofoilers: since we know it can be done it is only a matter of time before a boat suitable to singlehand heavy(190-220lb./86-100kg.) people or two people becomes a reality. If the numbers are done well keeping SA, RM and foil loading in the right range with an efficient rig these boats will foil early and well-upwind or down-no doubt about it!

But no matter what happens in the future monofoiling as a practical race winning technology started with the Moth Class and is probably one of the most historically significant developments in sailing in the last 100 years.

According to the Johnson 18 statistical reference page the 49er has 2.68 times the sailing weight of a Moth
and 2.65 times the Sail Area of a Moth (upwind). Definitely in the ball park. Crew weights based on 160lb.s(72.7kg's). In designing the Peoples 2 person foiler you wouldn't need the huge asy spin of the 49er or the wide heavy(263lb./ 119.5kg.) hull of the 49er and ought to be able to knock 68 pounds(30.9kg.) off the design for a two person foiler. It's right there staring us all in the face-thats why in an article in Seahorse magazine Ian Ward, another great Moth pioneer, proposed a SERIES of monofoiler classes! This is a revolution in SAILING not just in the Moth class....
Moth with 160lb. crew;all up 220lb.s or 2.58 lbs. per sq.ft.SA.
49er with two 160lb.;all up: 583; crew=2.55lb.s per sq.ft.SA
Peoples foiler(modified 49er) 2 160lb. crew;515 all up; 2.25 lbs/per sq.ft. of Sail Area or dramatically better than a MOTH almost(depending on rig)guaranteeing upwind foiling in light air!
Don't tell me it's not possible.....

Sunday, September 7, 2008

aeroSKIFF 14

Features of the aeroSKIFF 14:
TARGET SPECIFICATIONS / aeroSKIFF 14 / based on 250lb. max crew-drawings in post 15 based on 220lb. max crew.
1) LOA 14'8" Beam 12'(drawings in post 15 show 10' beam-beam may be increased to reduce buoyancy pod size and to help make crew weight range wider)
2) Target ready to fly boat weight: 120 lb.s
3) Max Crew 250lb.s ; target minimum crew 120lb.
4) Flying weight: 370lb.s
5) SA 143 sq.ft. square topped, camber induced , main only, unstayed mast ,extended luff, modified wishbone, midboom sheeting.

6) Standard main foil area 1.68 sq.ft.
7) Mainfoil loading @ 80% 176lb. sq. ft.
8) Rudder foil area 50% mainfoil area.
9) SA/mainfoil area: 85sq. ft. per sq.ft. foil area.
10) "Wing Loading"( all up weight divided by SA) =2.58lb.s per sq.ft. SA.
11) Draft ,off foils; foils extended= 3.75'-variable.
1) Forward third of sail comes completely down to the deck; the boom is a modified version of a wishbone boom with a cross member just forward of mid length that takes the mainsheet. The sheet is led to a traveller on the forward beam allowing the sheet to come from forward. A twin vang set up will be used should a vang be required.
2) Foils retract to facilitate beach launching.
3) Sliding single bench seat; slides easily and contains ballast compartment for one design class weight equalization system.Motion control system that prevents runaway seat in adverse situations.

4) Standard foils optimized for low speed takeoff; optional tip extentions; optional high speed foils.
5) Buoyancy pods approx 1.56 cu' per side; larger optional pods available for training.(see approx 3 cu. ft. pods illustrated in the sketches in post #15)
6)Rudder: unique design slides up and down in daggerboard style slot; stepped rudder flap designed to allow variable rudder area between non foiling and foiling; Target is to have rudder throw and sensitivity the same on or off
7) Double ended hull facilitates earlist 0 to takeoff; facillitates pitch change to allow early takeoff though foil system may not require this.
8) Trampoline each side with heel cutouts allowing quick, secure seat movement.
9) Foils designed to take loads imposed by jumping which can be initiated by twisting hiking stick(s).System bypasses wand but still utilizes forward /rear foil interconnect.
10) Variable main foil "gear shift" angle of incidence adjustment. From "set it and forget it" to fine tuning main foil drag.
11) Exceptionally wide crew weight range ; one design cass races wil be sailed at the 250 lb.s crew weight. Speed runs will be able to be made with lower crew weight as long as RM is addressed.
12) Wand controlled altitude with height adjustment. Set it and forget it or tweak it. Unique averaging wand system to improve choppy water response including fore and aft foil interconnect and wand bypass for smoother flying and better jumps.
Jumping is an important part of this foiler design because we think it will add to the value of the boat and to the fun of flying this foiler.

Friday, September 5, 2008

foiler weight

So many experienced foilers have been deluded into thinking that to have an effective singlehanded foiler it had to be all carbon and cost a fortune because they believed that WEIGHT was the single most important factor in foiling. IT IS NOT!! The most important single factor to determine "foilability" is not weight but the "Sail Loading"(weight divided by sail area).

RS600FF all up ready to sail weighs AT LEAST 167 lbs. That is 2.53 times MORE than a MOTH! Repeat, the RS600FF weighs ,ready to sail(minus crew), 2.5 times what a Moth weighs, ready to sail(minus crew).

There are other factors that will contribute to a foilers speed around a course,of course. But no single factor is as important as this power to weight ratio:
1) weight/SA on the RS 600 with a 160 lb. crew= 2.49 lb. per sq.ft.SA
2) weight/SA on the Moth with a 154lb. crew(Rohan)=2.558 lb. per sq. ft.SA

This means that even though the RS600FF is 2.5 times,repeat 2.5 times, as heavy as a Moth in racing trim with a crew it has a BETTER power to weight ratio.

Again, this is very significant for the eventual introduction of a reasonably priced peoples foiler. And it flys in the face of the constant drumbeat from some Australian (and other) foilers and foiler wanabes that weight is the single most critical factor-it is not.

This is big ,guys -in many ways starting with the fact that you DON"T NEED AN ALL CARBON HULL. Think how that could reduce costs. If a boat was built with a hull having a length to beam ratio like a Moth with a bigger rig like an RS but better aerodynamically like a Moth rig it could be lighter than an RS and be built from less expensive materials. Not speculation or theory: PROVEN FACT!

A Peoples Foiler could easily be configured for very light wind takeoff, or very high top end speed -probably with the same foil set with removable tips. As to pushing the limits I believe I am one of the first people that have ever suggested that jumping a foiler intentionally with a boat designed for it might be A LOT OF FUN.

There is a lot of room for a carefully designed easy to sail, beachsailable foiler. The design constraints are much less stringent than people like Phil, SimonN and others have been saying. And the RS proves it beyond a shadow of a doubt: weight is NOT the major determinant of a foilers success-the power to weight ratio is(among other factors).

Now isn't that sexier than a girl in good shape in a quality bit of lingerie under her little black dress?

Thursday, September 4, 2008

BMW ORACLE Racing monofoiler

you can't deny the proof the new BMW ORACLE RACING boat is the worlds biggest monofoiler.

This photo shows how well the buoyancy pods work, and you can see the guys in the steering pod who are operating the manual foil controls.


My 16' foiling keelboat

So here is a sneak peak at the keel of my 16' foiling keelboat. Allup 160 +120lb keelbulb+ the sail area to foil off wind with a better POWER TO WEIGHT RATIO than a Moth. It's this ratio that counts-not just weight. Of course, the thing has to be designed very carefully for it to work as mentioned earlier.

Saturday, August 30, 2008

ultimate family daysailor

I'm very interested in comments about the concept as a boat and as a product. It is a dinghy with a small keel; it is not a sportboat. Closest to it is the Laser Stratus except that this is half the weight and the hull is much narrower. It only foils DOWNWIND, has manual controls and is built for JUMPING.
This be the ultimate two person boat/family day sailor.
LOA 16-17'
Beam 12' (easily foldable for trailering)
Hull+ rig ready to sail weight 160lb.(minus ballast)
Ballast in bulb keel-120lb(self-righting from capsize or pitchpole) only etc.
Crew weight nominal 320lb.(sliding bench seat)
Upwind SA 150 sq.
Downwind SA 300 sq.ft.
Mainfoil on keel strut(at bulb)
Rudder foil

----Idea is to provide a safe, very fast two person boat that would be designed to foil down wind: round the mark,pop the spin,deploy the wand and whoosh....
----Uses modern ideas from several different types of boat to provide a new kind of sailing experience. Could be configured in a number of ways-for instance single handed main + spin only. Four people (2 adults, 2 kids main+ jib daysailing only).
Design configuration for racing: Two people ,max 320lb (more or less).
----Sliding bench seat P&S-NO HIKING NO TRAPEZE.
---- Manually controlled 100% self righting
----Power to weight ratio off the wind better than a Moth.(W/SA=2.0)
----Small buoyancy pods on outboard of rack

Regular readers will note this is different than my other designs because the numbers are different and this one includes 100% automatic self righting with manual self riighting controls; and the buoyancy pods are smaller.

Friday, August 29, 2008

hope it is adjustable

Is the f-box adajustible when sailing or not?

A fistfight broke out today in sailing anarchy over adjusting the fbox. It was this is very interesting-what in hell was going on? One guy says yes the other guy says no??!!

Damn, its a good idea-hope it is adjustable.
* if it was designed right it would surely work well....

Saturday, August 23, 2008

eliminate the gantry

The gantry (in my opinion) is a rule induced abberation which is NOT necessary for a successfull foiler design. In fact, there are really good reasons why it should be eliminated:

1) by allowing the hull to be a bit longer the available hull buoyancy is increased so the L/beam ratio can be increased reducing resistance and allowing the boat to achieve takeoff a bit sooner.

2) In my humble opinion, it is somewhat ugly and help creates a "contraption" appearance to some onlookers.

3) When taking off without an F-box(angle of incidence control) a gantry (and transom)drags when the boat is pitched bow up.

4) The ONLY reason for a gantry is to allow the foil footprint to be better on a boat NOT DESIGNED FOR FOILS IN THE FIRST PLACE.

Sunday, July 13, 2008

A Peoples Foiler at last?

From Adam May:
"Oh and Linton's latest foiler - a more of a foiler for the masses was also out yesterday evening. I didn't get any pics of it foiling, and few details are known about it yet so I'll save that for another post if I can find the time."

Also a mystery foiler was seen with a jib in Weymouth 7/13/08

I wonder if they are using manual control? Any true peoples foiler will need it, especially when jumping.

Saturday, July 12, 2008

Repeating past glory

Well the X21 is moving along-Time to work on it is a strruggle between my internet forum posting commitments. I was quite suprised the other day when someone brought up my past success the Kona Kat.

Building the Kona Kat was a great experience despite the idiots that said it was completely pointless and that it would be slower and heavier than a windsurfer.

Well we showed them-we sold 180 units and I got my first patent for the cone-shaped member.

Sport Boat Foilers

With the phenominal new Super Foiler Mirabaud making history NOW it seems like a good time to revisit these ideas I've thought about and worked on for several years:

There are some really exciting sportboats available now and at the end of this post are some interesting websites particularly the one with comparison statistics of a few current boats. For purposes of this post I'll define sportboats as high powered keelboats between about 20' and 40'. Some boats are much higher powered than others as you'll see in the comparison table. They should be able to plane (or foil). Ocean racing versions should be self-righting.
After doing an exploration of the feasibility of a foiling 60' monohull keelboat, it occurred to me that the next big advance in monohull foiling would probably be with a boat that fits the definition of sportboat so I 'm presenting very preliminary numbers for a two person and three person "Sportboat Foiler":
Two Person
---LOA 24'
---LWL 24'
---Beam 18.6' (overall, incl. racks)
2.4' at waterline
---Draft 6.5' keel,foils retractable
---Sail Area 586sq.ft. upwind and downwind
---Boat weight,incl. rig and ballast-1100lb.
---Ballast 490lb. (110° canting keel) 44% ballast/displacement ratio w/o crew
---Displacement (incl crew)-1420lb.
Three Person:---LOA 24'

---LWL 24'
---Beam 10.73' (overall incl. racks)
2.4' at waterline
---Draft 6.5' keel and foils retractable
---Sail Area-600 sq.ft. upwind and downwind
--- Boat weight- including rig and ballast-1100lb
--- Ballast 490lb.( 110° canting keel) 44% ballast/Displacement ratio w/o crew
---Displacement, incl. crew 1580

---LWL 24'
---Beam 18' (overall incl. racks)(2 on trapeze optional)
2.4' at waterline
---Draft 6.5' keel and foils retractable
---Sail Area-650 sq.ft. upwind and downwind(except in light air then 1200 downwind)
--- Boat weight- including rig and ballast-1100lb --- Ballast 490lb. 44% ballast/Displacement
ratio w/o crew
---Displacement, incl. crew 1580
Take Off Boat Speed is 6.5 knots which would be achieved in a 6-7 knot wind with 650sq.ft SA
Configured for early take off using a 63412 section at a mainfoil angle of attack of 6 degrees and a 20 degree mainfoil down flap angle.


Other comparisons:
-- -Sail Loading(weight divided by SA)- Two Person=2.42 lb. sq. ft. ; Three Person= 2.69 lb. sq.ft.; Three FIXED 2.43(#2 & #3 this ratio better than a MOTH)
---Mainfoil Area- Two Person=7.1 sq.ft. ; Three
Person= 7.48 sq.ft., Three Fixed 7.64 sq.ft
---Mainfoil Loading- Two Person=158lb. per sq.ft.
Three Person=169 lb. per sq.ft.
---Sail area per sq.ft. mainfoil area- Two Person =82.5 ; Three Person=80.2 ; Three Fixed=86.8
Note: Two person takeoff profile is approximately equal to a Moth with Rohan Veal aboard;
Three Person approx. equal to a Moth with a 160lb. person aboard.
---D/L Two=45.6 Three= 51
---SA/D Two= 74.3 Three=70.9 Three Fixed=78.4
---SCP/total weight Two=42% Three=34% Three FIXED 38%
Three person fixed keel would be 100% selfrighting w/o crew interaction:BALLAST/DISPL. RATIO SIGNIFICANTLY BETTER THAN T780. Ballast in this keel is not used for sailing RM-just for RIGHTING. Boat sails with 20 degrees veal heel adding 21 % to RM.
Both canting keel boats would be designed to be rightable by moving the keel; and a 100% self-righting foiler(no crew action required) is possible------------------
Weights for the hull and rig were derived from EXISTING boats that have hulls ,for the most part, twice as wide with over double the area anticipated with these boats. The hull would be very narrow -not much over three feet wide(at the deck) with possible flare out forward for a minimal cuddy cabin. The hull would be double-ended. In comparisons with the other boats in the table below the Sail area to wetted surface ratio of both versions above is probably greater than any other boat even INCLUDING the wetted area of the hydrofoils.(8.27/1 vs. 4.7/1 for the Martin 243).

I did this to show how incredibly close we are to having one of these boats actually built; the technology required to do this is available now and I hope it won't be long before "Flying Keelboat" really means flying...

Friday, July 11, 2008

Foiler 18vs "Normal" 18

Thomas Jundt sailed the 18 europeans with his 10 year old 18 with foils -not Mirabaud. I thought their chances were pretty poor sailing a 10 year old wide 18 converted to a foiler. In no way is this ideal or representative of the utmost in bi-foil technology. A skinny hull would be faster especially in marginal conditions. If "rules" weight would make the "new" foiler 18 artificially heavy -then fuck the rules-the point is to demonstate the technology-not antique rules.

Let me summarize it-as I understand it: when there was wind the foiler kicked ass. A foiler as light as the newer 18's would have probably kicked ass on and OFF the foils-particularly with a big lite air spin.

Thomas sent me an email and here is what he said about how he went.

In none flying conditions we are slower (the second race) :

- a bit slower upwind, the additionnal drag of the foils seams not to be too penalizing

- but much slower downwind, our head sail was a 20 sqm code 0, way not enough against the 65 sqm assymetrics

My conclusion :

- dispite the fact that our boat weighs 220 kg compared to the newest ones at 155 kg (class rule minimun since 2005) we are competitif when foiling (wind at least 10 knots)

- the additionnal drag of the foils seem to be acceptable when non flying

- in non foiling conditions downwind without the big assymetric you're dead

- a new boat 155 kg, with foils in the hands of a trained crew would beat everybody by a big margin in most conditions

- unfortunately, foilers seem not to be welcome in the class



I'm not sure that with all the rancor there is-like outright hostility to Thomas at the Euro's-the 18 foiler class will develop. The Moth class has shown that seahuggers and foilers can co-exist in the same class. It would be a shame if the 18 class doesn't embrace foilers-a new class may result that will be much faster than the current boats. If thats the way it has to be -so be it.......

The potential speed of the FOILER 18 is huge! According to Rhoan Veal A Moth in the right hands can beat current 18' cats(that have repeatedly beaten 18 skiffs).

"Each race of our division started 5 minutes behind the F18's, but by the end of my three laps, I had nearly caught and passed most of them. The highlight was passing them one at a time (to windward and leeward) on a reach with their kites up! Only a few of the top guys on a Tornado and Hobie Tigers stayed ahead, but they wern't anymore than 2-3 minutes in front. Needless to say I am feeling extremely confident with my Mk4 Prowler now that I have all the configuration and teething issues sorted out. It took 8 months, but I think Moth development is a case of one step backward, and two steps forward. "

Anecdotal evidence for sure, but when combined with what Thomas Jundt says shows that a FOILER 18 designed from scratch as a foiler would beat the crap out of ANY boat its own length.

A few people I've talked to think a the next big area of foiler development will be a two handed foiler. I agree if it is designed from scratch as a foiler-and not a coverted I14( or converted anything). Converted 14's on foils (and Mirabaud):

My first BLOG post

Since everyone else is BLOGGING about their foiler achievements, I thought I should too. First some history. Most people that know me keep asking what I have been sailing. Here is the list in no paricular order 


windmill(many firsts incl District Championship), thistle,fish class(many lasts and a few firsts),hobie 14,hobie 16,e scow, US 1(several 1sts etc),14'high performance experimental tri, 16' experimental cat,20' high performance experimental tri,TS 18(80+),Kona Kat (about 180) aeroSKIFF One, aeroSKIFF 2-X21-T(as we speak),worlds first production rc sailing multifoiler,worlds first rc monofoiler(as far as I know),worlds first production rc spinnaker boats,worlds first video piloted rc helicopter, 4 US patents including K Foil,"3D SAILING" trademark(sold),numerous other trademarks. Several new patents in various stages on foiler control systems.
Oh, yeah: learned much from Dr. Sam Bradfield and a book or two......