Flight One-a New Kind of Performance One Design Dinghy

Flight One-a New Kind of Performance One Design Dinghy/ C-Foil

This is a concept that I hope to see spring to life in one or more designs-all with one thing in common: the very unique retractable single curved lifting foil/daggerboard( C-Foil ).* This was one of those ideas you get in the middle of the night that gets your heart pounding and your feet moving to find a notebook to write it down/sketch it out.
Flight One, Version 1:
--what it isn't: it is not a full flying hydrofoil like a Moth,
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--what it is:
1) a performance single hander that can be sailed by two,
2) a performance single hander that is fun,easy, and exceptionally comfortable to sail,
3) a performance single hander that uses a retractable, single curved lifting foil( C-Foil) to increase speed and improve handling. The foil will support 60% or so of the total weight of the boat as boat speed increases.
4) a performance singlehander that uses a sliding seat with a backrest for added righting moment and exceptional comfort,
5) a performance singlehander with retractable foils to allow off the beach sailing. The single curved main foil( C-Foil) when retracted allows two replaceable tips to stick below the bottom of the boat so that the hull doesn't touch sand.
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--history- the curved lifting foil( C-Foil) that is the centerpiece of this concept has a long history in the design of high performance sailboats. Starting many years ago in trimaran designs where they were developed to a high level in ORMA 60 footers and today in many multihull designs from the gigantic Banque Populaire to the Nacra 20, A Class and C class catamarans among many others. Relatively recently, dual curved lifting foils have been applied to the Open 60's with Virbac-Paprec 3 winning the Barcelona World Race by a large margin using them.
Well, that was one hell of an inspiration to me-the first time in history that lifting foils had been used on a keelboat to win a major ocean race. I thought a lot about it and it seemed like a natural to use these foils on dinghies-here is the original thread-including a bad idea I had that was to have the dual foils pointing outboard. Thanks to Greg Ketterman and others for straightening me out on that one:http://www.boatdesign.net/forums/sailboats/dinghy-design-open-60-influence-36401.html . But that all led to what seems like a good idea for a dual foil boat and then, after trying hard to come up with a simpler system, to my "eureka" moment with the single curved lifting foil( C-Foil ).
Reference material: http://www.boatdesign.net/forums/hy...lifting-foils-monohulls-multihulls-37508.html
-- the idea: See the sketches below(and in subsequent posts as this concept is further refined). Basically, there is a single, curved asymetric foil( C-Foil ) that slides athwartship in a trunk that is partially open and jointed:
1) the top center of the trunk can be moved fore and aft to change the angle of incidence of the lifting portion of the foil only-the incidence of the vertical portion is not affected. The board can be accessed by hand or by other means to move if the auto system is not used.
2) the sliding seat mentioned above can be tied into the sliding board to allow automatic side to side board movement.
3) the relative side to side position of the board can be set with a simple "relativity" control that allows the total amount of vertical lift developed by the board on either side to be adjusted from max lift to almost no lift while still working automatically, if desired.
4) Since the board( C-Foil ) is not conceived of to lift the boat clear of the water(on a regular basis-stuff happens), there is no requirement for an altitude control system(wand) as on a Moth.
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--the rationale: Exceptional Comfort, Exceptional Ease of Sailing, Foil Assisted Speed and Performance!
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A note on the Flight One Concept: there are areas of this technology that could be patented but I am absolutely not interested in that. I'm interested in trying to inspire others to help refine this design or to use this technology with no strings to do their own design-with or without my help. I believe that this concept has incredible potential for developing a unique dinghy that could be a major breakthru in dinghy design. Much more to come!!
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* UPDATE- 8/11/11--To eliminate having to say "retractable single curved lifting foil/daggerboard", I'll just call it C-Foil from now on.

Rough Sketches-click on image:

 

Flight One / RS Dinghies and some others

Here are the specs on some singlehanded dinghies produced by RS in the UK:

1) RS 100(hiking)
LOA-14'
Beam 6'
hull shell 121lb
sailing weight 176lb
SA
asy spin 134 sq.ft.

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2) RS 300(hiking)
LOA-14'
Beam 6' 7"
hull shell 128lb
sailing weight 165lb
SA-rig A 99sq.ft.
rig B 107 sq.ft

==============

3) RS 600(trap)
LOA-14'8"
Beam 6' 4"-7'
hull shell 115lb
sailing weight 167lb
SA-main 131sq.ft.
reefed 114 sq.ft.

==============

4) RS 700(trap)
LOA-15' 5"
Beam 6' 4"- 7' 8"
hull shell 123lb
sailing weight 174lb
SA-main 137sq.ft.
spin 166sq.ft.

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And some other modern singlehanders:

1) Contender(trap)
LOA-16'
Beam 4.92'
hull shell 180lb
sailing weight ???
SA-main 116sq.ft.

==============

2) Swift Solo(trap)
LOA-14.5
Beam 6.4'
hull 169lb
sailing weight-all up boat 196lb.
SA-main+jib 152sq.ft.
asy spin 265sq.ft.

===============

3) Musto Skiff(trap)
LOA-15'
Beam 7.7'
hull shell 121lb
sailing weight-all up boat-176lb
SA-127sq.ft.
asy spin 167sq.ft. sq.ft

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Flight One-a New Kind of Performance One Design Dinghy / C-Foil

Of all the singlehanded dinghies in the previous post not a single one uses "foil assist"-where a lifting foil of some type can reduce the displacement of the boat. In fact the only dinghies that do use foil assist are the I-14 and National 12, some Cherubs and the SK4 skiff as best I know now. Contrast that with a fairly large number of small beach cats and multihulls up to 20' that use lifting foils for "foil assist" as a matter of course.
Somethings not right here and it's going to change.
Foil assist on these monohulls lifts a small percentage of the overall sailing weight on these dinghies-for instance on the I-14, it is only 89lb nominally. On a Nacra 20 cat it can be a much higher percentage and lift is fully adjustable.
On Flight One the lift due to foil assist will be closer to a maximum of 60% and it will be 100% adjustable by the skipper. Note, that on these monohulls the vertical lift is from a rudder t-foil, which allows the crew to be further aft upwind or downwind adds to crew weight to hold the stern down. However, in very light wind these foils cause drag in excess of any improvement in speed. Thats where the curved ,retractable lifting foil( C-Foil ) comes in: in conditions where lift is not productive the lifting portion of the foil can be reduced without affecting the area required for lateral resistance!
If it is decided that a rudder T-foil will be beneficial, then Flight One will be able to use a system already devised for another boat of mine that allows a simple way to retract the rudder hydrofoil.
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--- UPDATE- 8/11/11--To eliminate having to say "retractable single curved lifting foil/daggerboard", I'll just call it C-Foil from now on.

===============
See pdf on rudder t-foils below:



pictures: L to R ,I-14 rudder t-foils, National 12 rudder t-foil.

 

Flight One / Foil Assist / DSS / T-foils(2)

DSS--One of the most recent developments in monohull "foil assist" is "DSS"-Dynamic Stability Systems invented by Hugh Welbourn. Here is a thread with his most recent-and coolest to-date-example of the system in action. Be sure to watch the exceptional video.
http://www.boatdesign.net/forums/sailboats/quant-28-foil-assist-keelboat-dss-38421.html

Haven't seen an example of DSS on a dinghy and I'm not sure whether it would work or not. It would be able to add RM and the crew would have to handle moving the foil every tack as with the single sliding curved foil on Flight One. But the boat would still require a foil for lateral resistance.
My gut feeling ,at this point, is that the curved lifting foil would be more efficient in developing vertical lift but the vertical lift from DSS would also add to the boats righting moment. I think it is too early to say that one system would definitely be faster than the other-both are "foil assist" and both have a lot of potential. DSS is actually being used on the remarkable Quant 28 and another sportboat "Brace,Brace, Brace". DSS is a tribute to Hugh Welbourn's ingenuity and persistence.
It does appear that the Flight one system( C-Foil ) would be significantly simpler and possibly have a greater range of adjustability and therefore be more suitable on a singlehanded dinghy.

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T-Foils (2)-Another configuration of "foil assist" for dinghies could be a version of the bi-foiler system pioneered by the Moth but with smaller foils and designed so as to not require an altitude control system(wand).
The main advantage of a system like this would be the absence of a sliding foil that has to be moved-by the sliding seat or directly by the crew.
The main disadvantages would be:
1) the lack of ability to reduce the area of the lifting foil to configure the system for different wind conditions. The Flight One system( C-Foil) is infinitely configurable to the lowest drag system for any condition.
2) According to Greg Ketterman the curved lifting foil will be significantly more efficient that the main t-foil in this kind of configuration.
3) One of the greatest advantages of a bi-foil configuration in a fully flying foiler is its ability to use veal heel. That would not be possible with the "foil assist" version of this configuration.
4) The main t-foil hydrofoil would not be fully retractable for beach sailing-it would always hit first unless some method was designed that allowed the foil to fit flush with the bottom.
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All in all, when compared to other forms of foil assist I'm convinced that the Flight One system( C-Foil) is simpler in every case and may be faster in most cases with a higher degree of vertical lift. It will definitely be more adjustable to varying conditions than any other system as best I can tell now.

 

Flight One-a new kind of Performance One Design Dinghy / C-Foil

Sliding Seat /Comfort--
This is as important to the Flight One concept( C-Foil ) as is the curved foil because the idea is to break the mold in performance dinghy design. That means getting away from super athletic torture chambers by using variations on movable ballast systems. The idea, to me, is to be able to sail a fast monohull in the most comfortable way possible to allow participation by people that might not want to hike or use a trapeze yet be able to, at least, match the performance of some trapeze dinghies. This is a tough bill to fill and will require quite a bit of development.
Sliding seats of one type are used by the International Canoe, the Skate and a maybe a couple of other boats. They are ,essentially, a plank that you sit on as far out as you can get. The variation I want to develop will be a bench seat with a backrest designed with major comfort in mind. The seat(one on each side) will be able to move quickly and create righting moment equivalent to a trapeze dinghy. I think a seat like this will encourage more people to give this kind of performance dinghy a shot because of the ease of use and comfort of the seat. In addition, the racks supporting the seat will be designed to have buoyancy pods far outboard that will prevent a capsize should the seat be in max position and the wind quit.
The seat will also be able to be used to move the foil side to side.....
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UPDATE- 8/11/11--To eliminate having to say "retractable single curved lifting foil/daggerboard", I'll just call it C-Foil from now on
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pic-Skate with twin sliding seats...click on image:

 

All:

Trapezes are not torture - they are the most comfortable/economical/cost effective way of increasing righting moment - and this has been confirmed over many decades of voting (by real dollars spent) by a lot of sailors. Long before the Skates and other two man boats, the UK Hornet class used sliding seats.

Considering complexity, added weight, reliance on mechanical 2-D carriage & tracks (fore/aft as well as in/out), multiple bearing surfaces and use in a hostile corrosive environment, sliding seats do provide excellent righting moment augmentation - but with inherent compromises as well. This concept appears to be heading down the road to having two distinct seats - one for each side - adding more complexity yet again.

Traps add only two wires, tiny mast fittings and one harness to the equation - and they allow movement in three dimensions. A sliding seat adds a carriage and plank/seat - and it chews up a huge portion of precious real estate in an already small boat.

I know it is hard to resist the appeal of selling people on the idea of a dinghy slider-supported reclining Lazy Boy/Barcalounger.

In actual real world use, current sliding seats demand the same kind of athleticism, speed and reaction time as trapezes. Dancing around a sliding seat (in normal maneuvers) works in the single hand International Canoes, because you've got the very crowded and tiny dance floor to one's self. Putting all this (with individual port & starboard planks/seats) in the people space of a dinghy, along with dual trunk articulating adjustable curved lifting foil looks to be mildly challenging.

Please don't think of this as negative criticism - it is just to help outline some of the possible challenges in front of promotion of this concept. I very much look forward to full-sized demonstrations of this boat on the water - and hope it becomes a huge success. I'm sure innovative thinking will solve all these issues.

I also envy the ability to fund, promote, build and maintain all these projects concurrently.

Best Wishes!

--
CutOnce

 

Flight One-a New Kind of Performance One Design Dinghy/ C-Foil

Great comments, Once-thanks. I've always loved using a trapeze from when I was very young on a Flying Dutchman to more recently on a Hobie 16. I see no reason why a trapeze version using the single curved lifting foil ( C-Foil )technology
couldn't work very well.
My version of the concept will try to develop the sliding bench seat which I think may be less daunting to newer sailors than a trapeze and probably more comfortable to some people. The sliding seat on my version of the concept boat would also allow the seat to be tied into moving the foil side to side making that function pretty nearly automatic.
There is lots of room for different designs incorporating the C-foil and I hope others will take an interest in helping to develop designs suitable to utilize this technology to the fullest.

 

Flight One-a New Kind of Performance One Design Dinghy/ C-Foil

Some notes from the original thread where the C-Foil(single curved lifting foil) was first mentioned-edited for this thread:

A summary of thoughts on a single curved foil used on a dinghy for lateral resistance and vertical lift-so far-version 2:

1) First application I've found where a single curved foil could replace the two foils required in every other current application of curved daggerboards,
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2) Lots of potential, during the design process,to play with the radius of the curved board to maximize or minimize vertical lift,
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3) Seems that it may be superior to a "normal" daggerboard in every case including storage(retraction w/o hitting the boom, foil can be asymetric etc.),
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4) Problems include how to grip the board to slide it from one side to the other.
Might be possible to use some sort of hand crank, line that rotates a drum between the two sides of the continuous trunk or? (See below)
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5) Despite my first impressions earlier the C-Foil does not appear to be able to increase righting moment significantly, though this may change as the idea is refined. At the same time, the single curved foil does NOT decrease righting moment as does a curved lifting foil on a multihull.
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6) When considering this single curved board system/ C-Foil it becomes abundantly clear that the use of curved lifting foils are not only possible on dinghies but can offer significant performance potential.
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7) a boat using the single foil would be simple to right regardless of whether the boat capsizes to leeward or to windward using a righting line or maybe just crew weight hanging on the foil.(see rough illustration below)
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8) a major design advantage of the single curved foil/C-Foil-(with its continuous, partially open, athwartship curved trunk) compared to a t-foil used for "foil assist" is that in conditions where vertical lift produces too much drag the foil can be partially retracted eliminating the unwanted drag due to vertical lift. In addition, the foil can be retracted a small amount at a time to "tune" the vertical lift to the conditions. To further aid in this it appears that a system can be used that would adjust the angle of incidence of the vertical lifting portion of the foil(without affecting the lateral resistance portion) by designing the athwartship, partially open, continuous trunk for this facility.
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9) A retractable gantry supporting a small t-foil rudder may or may not be an asset in pitch control for a dinghy using the single curved foil. A unique, rotating, rudder system where the rudder trunk actually rotates 180 degrees may be possible to allow the t-foil to be retracted 100% reducing unnecessary drag in light conditions. The rudder would still slide up and down within the trunk. It looks like a system like this could be done fairly simply and robustly-not much more complication than a kick up rudder design. More on this to come.
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Movement of C-Foil

I've looked at a lot of possible solutions for this including using some sort of roller that touched the board and allowed it to move with a hand crank or another means of causing rotation.
The breakthru comes in post #16 of this thread: http://www.boatdesign.net/forums/sailboats/quant-28-foil-assist-keelboat-dss-38421-2.html

Hugh Welbourn makes a comment-the first I've ever read- about how the DSS foil on the Quant 28 is moved. It has a roller in a wetbox where the shaft of the roller is sealed like a stuffing box-only simpler. Cranking or rotating the roller slides the foil athwartship! It is a brilliant idea for that boat and foil system and a version of it would work w/o the wetbox for the single curved dinghy foil. The break thru is the certain knowledge now that a roller system will work!
The foil is a single molded asymmetric foil that slides in a trunk across the boat.
When centered it is retracted and it can be deployed on the port or stb side and adjusted at will. Using the roller system it could be tied into a sliding seat so that it is automatically deployed tack to tack.

rough sketch L to R, 1) possible method of incorporating system similar in function to method of sliding DSS foil, 2) Method of righting C-foil equipped boat.

 

An interesting idea.

The drawings do not indicate which way the boat is going, but I'll assume the convex side of the curve is to leeward and the crew is on the windward wing.

The only problems I see is there is a whole lot of foil area for the amount of lift being provided and it ends up not being well supported in the boat, when fully extended. Hoop like wings on airplanes were tried in the '30's and once in the '50's, but they never took off. And probably for the first reason I cited above.

Another problem is that the bending moments on this presumably high aspect ratio foil are going to be enormous. It's going to want to bend into a tighter circle. And when it does, it will produce more vertical lift which will make it bend even more. Being supported only at where it comes out of the hull, the load is going to be concentrated there. Where ever you have extreme localized bending stresses, there is bound to be trouble. Much of engineering is the art of avoiding situations like that. As the foil bends into a tighter circle, it is not going to want to retract back into its case. In order to keep it from binding, you are going to have to luff almost to a complete stop before you can retract it and shift it to the other side. This, in a very light boat with an enormous spread of sail, is going to be quite embarrassing. Especially when the boat fails to swing its bow over to start the next tack.

I can think of one possible design that would remove the need for the curved board but accomplish the same goal, lengthen the righting arm so more sail area can be carried.

What I have in mind would look like a cross bow from the top view.
A lengthy cross beam would have an angled foil at each end. Each angled foil would be supported at each end with a vertical board, which would serve as lee boards as the foil would not lift the hull out of the water, but merely move the center of buoyancy/lift to leeward. The crew, of course would move to the opposite end of the cross beam as human ballast. In this situation, there is no need for retraction of any kind. When the boat is level neither foil need go deeper than the hull. The foils would be angled inward, so when the boat heels, windward foil comes out of the water and the leeward foil produces more lift.

What you would have is essentially a trimaran with the floats removed and replaced with foils, with hopefully, a huge savings in whetted surface area.

The main hull would have a dead flat run on its bottom similar to a Brown Searunner trimaran. The main hull would plane, but only after it reached a relatively high speed. The main hull would be quite narrow. Maybe one eighth or even one tenth as wide as it is long.

 

C-Foil

Sharpii, thanks for the comments! I'm not really concerned about binding etc because these type foils are used regularly on beach cats and other multihulls under much, much higher loads. It's a question of engineering and building the foil properly which I think can be done fairly straight forwardly. The foil, as you surmised, operates on the lee side of the boat and, because of its unique design, can be an asymetric section. On the Nacra 20, the curved foils can be adjusted under load,and while they don't have as much curve as these do they are under much higher loads laterally. The foil develops both lateral resistance and vertical lift and if it and the trunk are properly designed adjustment should be straightforward-at least while tacking.
Boats I've sailed with either a CB or daggerboard were either impossible to adjust under load or very difficult. More will be learned with experimentation-the new test model I'm building and the fullsize boat it represents use curved foils like this one( same radius) that are under even heavier load so I'll learn a lot there.
>Just one other point: the C-Foil as used in the Flight One boat does not add anything to the righting arm/ righting moment and does not permit extra sail-carrying ability. In fact, if it is not sailed flat and allowed to heel to leeward it could actually reduce the righting arm!
--
Take a look at Doug Halseys 18' tri in the picture below-it seems to be similar to your idea and was designed and sailed without amas-just foils and seems to work well. Check out the rough sketches for the Tantra II; it uses dual curved foils(one at a time, generally) that do increase the RM of the boat. You can read more about it in the thread linked in the first post. See the picture of the original (35 years old)Tantra hull showing the molded-in leeboard concept that would house the curved foils on the updated version. And the C-foil for comparison.
Also, shown below the NACRA 20 foils, and the tight curved foils for the Farrier F31:
click on image:

 

C-Foil

I think a boat using the C-foil could represent very advanced technology in dinghy design since it allows much more vertical lift than currently used as foil assist. It offers the potential to be superior to any current dinghy that isn't a full flying foiler and the technology offers the design latitude to develop high performance dinghies that can be much easier to sail than current performance dinghies. It offers options such as the use of a rudder t-foil or not, extended tip foils that prevent the hull from touching ground. And more including greater range and adjustability than most any other foil system.
Design latitude is the key because this technology can be used in small single handers as well as two-three person performance designs. For the same RM the C-Foil allows much greater efficiency allowing the SA/ws ratio to be higher with significantly improved performance compared to older designs with the same RM.
It's exciting- take some time and check it out!

 

Hi, Doug.

You got me thinking. And that is a very dangerous thing to do. I have strived years to develop a dangerous mind.

I started thinking about a boat similar in concept to the Quant but without a foil retracting mechanism. Then I thought of what to do when the foil nears the surface at speed. What if the bottom of it could become a planing surface, so it skips across the surface like a skipping stone.

That is how I came up with the contraption pictured below. The surfaces that are shaded are supposed to be below the waterline and the non-shaded ones are supposed to be above.

It is supposed to be sailed by a crew of two. Each wears a trapeze. One puts his feet on the edge of the wing deck and leans outward using the trapeze for support, while the other steers the boat.

As the boat heels, the foils on the leeward side produce more lift than those on the windward side and hopefully start lifting the boat. As the boat is lifted, its surface friction is reduced, allowing it to sail faster. As it sails faster, the leeward foils lift it even more, further reducing drag, and so on.

If it gets going fast enough, the main foil will break out of the surface of the water and start planing.

At least that's the thought.

I know the hull depth might not be enough, but this is to show the general concept.

As far as I know, the dagger board placement is correct.

Just thought I'd show you this for your entertainment.

 

====================
Thanks, Sharpii! According to the owner of the Quant 28 DSS works both when it is lifting in the "traditional" way and when it is just using the bottom surface,ie planing. I've always been concerned that the proximity of the lee foil to the surface might be a cause of too much drag but that is debunked by both Wellbourn and the owner to some extent. I'm sure more could be learned in two boat testing to see what happens with the foil planing and the other boat retracting their foil.
I think your idea is neat in its simplicity and might work well-you could fool around with foil areas and aspect ratio and do the boat fairly inexpensively.
I'll buy the beer if you get so interested you try it! Good thinking!

 

Thanks. Doug, for the kind words.

I was thinking of a name for this thing.

First I thought of 'mako', which is the fastest shark in the sea. Then I thought of 'tiger shark', then 'blue shark'.

The thing is, if it is ever built, I fear it could be beaten by a competently sailed windmill (which was where I got the beam and length from. The sail area is similar to a Hobie(r) 16, as far as I can remember it). So, to avoid severe future embarrassment, I chose to name it after what it most resembles: a surface to air missile.

Such naming of my designs is a tradition with me. Hence I have designs with names such as: 'box car', 'coal car', 'guppy', 'angel-fish' and even 'hog trough'.

Occasionally I will name a design in someone's honor, but only if I'm quite sure such a design will work as well as I hope.

If I ever get rich, I may well spend much of my fortune on mad boat experiments such as this. But, as a nine dollar an hour minus security guard, the only experiments I can afford to do are thought experiments.

Paper is cheap; it takes real money to innovate.

 

Flight One / C-Foil System

UPDATE: From the Quant 28 website-post 23, here: http://www.boatdesign.net/forums/sailboats/quant-28-foil-assist-keelboat-dss-38421-2.html
An illustration of the foil movement system that can be adapted to the C-foil
without the requirement for a sealed wet box. This can also be tied in to the sliding seat system(using a clutch) to allow fully automatic movement of the C-foil.