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.