KissCut-new Swiss Foiler

[Doug Lord]

Here is a google translation of the page: http://translate.google.com/translate?prev...history_state0= (http://translate.google.com/translate?prev=hp&hl=en&js=y&u=http%3A%2F%2Fwww.skippers.ch%2Frecord-et-proto%2Farticle.php%3Farticle%3D181%26sousCategorie%3D&sl=fr&tl=en&history_state0=)
LOA 4.5 m=14.7'
Beam 4.5m=14.7'
SA=9sq.m=97 sq.ft
weight est.=40kg=88lb.
Price-an amazing(!) $42,000US no peoples foiler if this price is accurate


the untranslated article: http://www.skippers.ch/record-et-proto/art...;sousCategorie= (http://www.skippers.ch/record-et-proto/article.php?article=181&sousCategorie=)

renderings from Vincent Gillioz article:

[ancient kayaker]

Wow, and I thought I could build light! Is that the fully-rigged weight or just the hull weight? If that's ready-to-sail there is some serious technology in that boat.

However, it seems to be just a design on file. It was supposed to be announced in April if my French is up to the task; I can't find any recent mention of it though.

I like the amas, nice safety feture, but it's hardly a people's foiler at any price. I think the peoples foiler will have to be much easier to sail, probably with angled foils and passive stability even if there is a speed penalty.

Thanks Doug for researching all these foiler sites, keeps us informed.

[bistros]

Wow, and I thought I could build light! Is that the fully-rigged weight or just the hull weight? If that's ready-to-sail there is some serious technology in that boat.

However, it seems to be just a design on file. It was supposed to be announced in April if my French is up to the task; I can't find any recent mention of it though.

I like the amas, nice safety feture, but it's hardly a people's foiler at any price. I think the peoples foiler will have to be much easier to sail, probably with angled foils and passive stability even if there is a speed penalty.

Thanks Doug for researching all these foiler sites, keeps us informed.

If 42K USD is affordable for a single hander, I wish I worked in the Swiss economy.

They started by saying the Moth was too athletic to sail and Mirabaud required assembling a team to sail. They quickly proposed their design as easier to sail and able to touch & go as a result of the amas.

I looked briefly around for evidence it was ever built and didn't find a trace either.

This type of unobtainium cubic dollar approach to foiling is diametrically opposed to the formula I believe necessary - cheap as dirt is the road I think is needed.

The Moth is still too expensive for a limited use fun toy. Face it, foiling isn't a legitimate sailing activity for all conditions. It is an activity that has a window of conditions that are fun, and outside that window it is either painfully impossible (light to no winds) or dangerous (high winds and equipment failure). Failure of either equipment or loss of wind basically demands that motorized support should be available for foiling venues. These boats do not paddle well (if at all), and broken parts render them fundamentally flotsam.

Because of this reality, I think foiling needs to be affordable enough that people can have their foiler as a second boat for use in the right conditions - much like kiteboarding or Formula board sailing. Even board sailors make sure conditions are okay before bothering to leave shore.

What would be the minimum price necessary to create a low cost foiler? Understanding concessions must be made to hit the price target. I don't think the Moth's demand on athleticism are outrageous, so use that as a base line for crew competency.

Real volumes may be possible if a low cost entry could be sold for prices similar to a Laser. 6K US is a fair estimate. Does this work?

--
Bill

[Doug Lord]

"The Moth is still too expensive for a limited use fun toy. Face it, foiling isn't a legitimate sailing activity for all conditions. It is an activity that has a window of conditions that are fun, and outside that window it is either painfully impossible (light to no winds) or dangerous (high winds and equipment failure). Failure of either equipment or loss of wind basically demands that motorized support should be available for foiling venues. These boats do not paddle well (if at all), and broken parts render them fundamentally flotsam."
-------------
It is simply not accurate to paint all foilers with the Moth brush-there is no reason that a monofoiler can't be rugged enough for use as a primary boat or that it has to be limited to certain conditions. Ideas are already in use that allow the RS600FF to be sailed in a wide range of conditions with it's reefable rig. It is far easier to launch than a Moth with it's wider hull and retractable daggerboard and rudder.
If you combine some of those features with the wider beam of the Swiss boat and substantial buoyancy pods/amas you have a boat that will be far easier to sail than a Moth and sailable in a wide range of conditions. Amac(designer of the Bladerider and Mach II) has said that the Moth would foil in 5 knots of wind with 4sq.ft more SA-it already foils before a windsurfer planes. A new boat could be designed to foil in the lightest wind and with a reefable rig and more beam could be as manageable as any other dinghy in strong conditions.
Since the inception of wand controlled bi-foilers in 1999 the development effort has been to make a fast bi-foiler-now more and more people are looking at ways-outside of the restrictions of the Moth(or any other class)rules to make an easy to sail bi-foiler.Jon Howes and Linton Jenkins have pioneered a new kind of foil that does not require a wand and could offer many advantages. Before a Peoples Foiler can be done preconceived ideas such as those above will have to be understood as not representative of all bi-foilers-but just the Moth.
Bladerider has already addressed the cost issue by developing an all glass Moth that weighs just a bit more than a carbon version. That kind of thinking applied to a bi-foiler designed from the get-go to be easy to sail in a wide range of conditions will eventually lead to a "Peoples Foiler".
-----
I'm convinced that the price quoted for the Swiss foiler is some sort of misprint-I'm working on getting more info.

[bistros]

It is simply not accurate to paint all foilers with the Moth brush-there is no reason that a monofoiler can't be rugged enough for use as a primary boat or that it has to be limited to certain conditions. Ideas are already in use that allow the RS600FF to be sailed in a wide range of conditions with it's reefable rig. It is far easier to launch than a Moth with it's wider hull and retractable daggerboard and rudder.
If you combine some of those features with the wider beam of the Swiss boat and substantial buoyancy pods/amas you have a boat that will be far easier to sail than a Moth and sailable in a wide range of conditions. Amac(designer of the Bladerider and Mach II) has said that the Moth would foil in 5 knots of wind with 4sq.ft more SA-it already foils before a windsurfer planes. A new boat could be designed to foil in the lightest wind and with a reefable rig and more beam could be as manageable as any other dinghy in strong conditions.
Since the inception of wand controlled bi-foilers in 1999 the development effort has been to make a fast bi-foiler-now more and more people are looking at ways-outside of the restrictions of the Moth(or any other class)rules to make an easy to sail bi-foiler.Jon Howes and Linton Jenkins have pioneered a new kind of foil that does not require a wand and could offer many advantages. Before a Peoples Foiler can be done preconceived ideas such as those above will have to be understood as not representative of all bi-foilers-but just the Moth.
Bladerider has already addressed the cost issue by developing an all glass Moth that weighs just a bit more than a carbon version. That kind of thinking applied to a bi-foiler designed from the get-go to be easy to sail in a wide range of conditions will eventually lead to a "Peoples Foiler".
-----
I'm convinced that the price quoted for the Swiss foiler is some sort of misprint-I'm working on getting more info.

Doug:

You have a bad habit of picking and assembling together arguments that are mutually exclusive to prove a point. There are some basic principles that just don't work well together anywhere but in your imagination.

Here are some of the issues and problems:

1) Generally, ultra low weight requires high cost exotic materials. Carbon, kevlar, epoxy and the like are expensive material choices that lower weight and maintain or increase strength.

2) Low drag means reduced wetted surface area and/or reduced form drag. Needle-like skinny designs have lower form drag and reduced wetted surface area at the penalty of stability and usability as a general boating platform. Wings necessary for righting moment in these designs have high aerodynamic drag.

3) Wider dinghy designs like the RS600 have higher form drag and higher wetted surface area when not foiling. They also have high windage and aerodynamic drag when foiling. These designs logically will foil later than low drag designs in marginal conditions.

4) Adding amas or as you call them "buoyancy pods" to an already wide bodied dinghy design like the RS600 will increase drag and lower potential performance more.

5) There is no magic wand allowing the addition of power without penalty. More power requires more righting moment. More righting moment means either the existing moving ballast (the operator) needs to move further from the centerline (increased moment arm) OR more weight is necessary if the moment arm length does not change. More weight equals less performance potential and more lift required to foil. More lift requirement means more drag.

My "low cost foiling" proposal was submitted to provoke thought on how one could achieve a basic foiler at the lowest possible cost, recognizing that every design is the sum of it's compromises to reach the designer's targets of price, performance, durability and value.

Returning to my original point, here are the conundrums:

1) Ultra low weight and strength generally requires exotic and expensive materials. Higher cost reduces the available buyer pool.

2) Safe and simple operation generally requires lowering the performance bar to add stability and simplicity.

3) Adding the design criteria of a "general purpose all condition sailboat" to the high performance foiling ability makes the design brief very broad. The broader the design brief, the more expensive and complex the solution.

I just can't see how you could come up with the magic formula for a People's Foiler - low/reasonable cost, simple and safe operation, high performance and usable as a general purpose sailing dinghy as well. Eliminate cost as a criteria and yes, it gets easier - hence the proposed Swiss foiler in this thread. They've made their choices and 42K USD is the price tag. Lowering the price tag means compromises which have major effects on the design brief. I highly doubt there is a huge profit margin in their price, given the low volumes and small buying pool at that price level. I disagree with you on the pricing - I do not think it is a mistake.

My idea was to fix the price target and then try to achieve the best possible result in the set price - reducing the design brief to fit the price. I'd like to see what is possible and how bad the compromises would be to fit the price.

To me, focusing on the critical components is required. Foils are the most critical component in a foiler. Everything else is less important. The #2 critical issue is the rig and it's efficiency and drag. The least important component is the hull.

I'm willing to bet quite a few of the homebuilt foilers out there were done at significantly lower cost than a Bladerider (even the glass/epoxy version). Once you move outside even a development class rule set, what could be possible?

--
Bill

[ancient kayaker]

Winds sufficient to fly a competition foiler are common enough, and "minimum foiling wind" don't tell us non-foilers an awful lot about what we would have to do to join the foiling ranks. I don't think the problem is one of power, no more power is needed to stay up on foils than to keep on planing, once the condition is achieved.

It is getting into these conditions that needs the power. Once speed starts to climb, and on certain points of sailing, the question of aerodynamic efficiency becomes an issue. But that's not needed just to have fun.

What would certainly "sell" would be a kit that could be added to an existing boat that would, conditions permitting, allow foiling. The foils could be retractable with a minimum of fuss, perhaps stored in the boat. It would be a sometime thing for most sailors, not worth a huge investment.

So what would be the minimum needed? let's assume we would like to add foils to a small boat like the Laser that's already capable of planing. Is the existing sail area and form suitable and what kind of foil area would be appropriate?

[Doug Lord]

So what would be the minimum needed? let's assume we would like to add foils to a small boat like the Laser that's already capable of planing. Is the existing sail area and form suitable and what kind of foil area would be appropriate?

=====================================
If you want to take off in the same wind as a Moth
you need a W/SA of 2.558 or less. A hull with a l/b ratio of much less than 10/1 will require a ratio substantially less.

Here is an interesting comparision of the Moth, RS600FF and Mirabaud:

It is extremely important to note that the comparison of foilers of different weights WITHOUT considering POWER is inaccurate. Weight is CRITICAL when comparing the performance of two identical foilers but WEIGHT AND POWER must be considered together when comparing different boats.
All three boats have proven on the race course to be extremely close in speed.
======================
Moth-
SA: 86sq.ft
Sailing Weight(includes crew): 220lb.
main foil area: 1.19 sq. ft.
Foil Loading(Lbs per sq. ft. at 80% max boat weight with crew):147.89
W/SA: 2.558lb. per sq.ft.(sail loading)
SA per sq.ft. of main foil area(a SA/ws ratio shortened to cover planform area of main foil only): 74.62
=======================
For ease of comparison foil areas for the next two boats were arrived at by using the same FOIL LOADING as a Moth.
Only upwind SA is considered. Moth crew=154lb.RS crew=160lb.; Mirabaud crew =3X160lb.
=======================
RS600FF
SA: 131 sq. ft.
Sailing Weight(includes crew): 327lb.
main foil area: 1.76 sq.ft.
Foil Loading: 147.89 lb. per sq.ft.
W/SA: 2.49 lb. per sq.ft.
SA per sq. ft. main foil area: 74.43
======================
Mirabaud
SA: 354 sq.ft.
Sailing Weight(includes crew): 854lb
mainfoil area: 4.61 sq.ft.
Foil Loading: 147.89lb. per sq. ft.
W/SA: 2.41
SA per sq.ft. main foil area: 76.78+++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++
Note the different weights of the boats . Then note the Sa/per sq.ft. main foil area-this is a comparison of Sail area to wetted surface when the boat is flying using just the planform area of the main foil for comparison-THEY ARE NEARLY THE SAME FOR ALL THREE BOATS. Note the W/SA is almost identical for all three boats. This means that all three boats will foil at about the same time adjusted for differences in rig efficiency(Moth probably the best) and for hull L/B ratio as a measure of early takeoff potential(Moth by far the best). As I just said there are other factors and details that will marginally affect performance but this clearly shows how close all three boats are in their ability to fly despite the fact that the RS is 2.5 times heavier than a Moth and Mirabaud is 5.6 times as heavy as a Moth.
What counts is power to weight ratio as a first look. A more detailed look showing a comparison of SA/ws ratios for all three boats reinforces the accuracy of the power to weight ratio.

[Chris Ostlind]

Doug,

You know that it's been right around four years since you started mentioning this whole thing about People's Foilers? In that time, not one boat has emerged as a candidate with the right stuff to be able to meet anything even close to the established criteria. Even your own, homebuilt effort seems to have morphed several times into different animals and none of them have seen the water yet.

Now, the whole world is well into a very deep recession economically and the available disposable income, which was supposed to drive a push into a People's Foiler as a viable product, has virtually dried-up and blown away.

Yet, here we are, still fooling around with the concept as if it has some sort of real potential in the marketplace.

Some things, Doug, are just not in the cards as workable entities. Perhaps it's time to recognize the market realities of a People's Foiler and move on to other, more fruitful expressions? The sailing world craves simple, easily purchased and sailed craft with modern, aesthetic design appeal that will move more potential buyers/sailors onto the water. The sport is dwindling in size, even in the recent good years of economic well-being. In bad times, such as these, the sales figures are seriously depressing.

Perhaps a good deep think as to the real definition of what is suggested by the term, People's, is in order before prescribing a craft that is more expensive, more complex and more maintenance oriented than other, entry-level recreational boats, already on the market...?

[Doug Lord]

Doug:

You have a bad habit of picking and assembling together arguments that are mutually exclusive to prove a point. There are some basic principles that just don't work well together anywhere but in your imagination.

Here are some of the issues and problems:

1) Generally, ultra low weight requires high cost exotic materials. Carbon, kevlar, epoxy and the like are expensive material choices that lower weight and maintain or increase strength.see 1 below

2) Low drag means reduced wetted surface area and/or reduced form drag. Needle-like skinny designs have lower form drag and reduced wetted surface area at the penalty of stability and usability as a general boating platform. Wings necessary for righting moment in these designs have high aerodynamic drag. Not true on a foiler where the characteristics of the boat on foils are determined by the foil design, altitude control system design and the distance between the center of lift of the main foil and rudder foil(footprint). The "skinnyness" of the main hull has to do with how early the boat will take off in light air and marginal conditions. The aerodynamic drag of wings for added stability have been proven to be dwarfed by the added RM-not just on foilers but on multihulls and skiffs as well.
3) Wider dinghy designs like the RS600 have higher form drag and higher wetted surface area when not foiling. They also have high windage and aerodynamic drag when foiling. These designs logically will foil later than low drag designs in marginal conditions.True, for the most part-a skillful designer can make up for deficiencies in one area by improving performance in others.
4) Adding amas or as you call them "buoyancy pods" to an already wide bodied dinghy design like the RS600 will increase drag and lower potential performance more. An RS600FF does not need buoyancy pods-and it is generally recognized among foiler designers that a high L/B ratio hull on a foiler is best for low wind speed takeoff. See also 3 above.
5) There is no magic wand allowing the addition of power without penalty. More power requires more righting moment. More righting moment means either the existing moving ballast (the operator) needs to move further from the centerline (increased moment arm) OR more weight is necessary if the moment arm length does not change. More weight equals less performance potential and more lift required to foil. More lift requirement means more drag.
Way too simplistic: look at the foiler comparisons below. Like all design, foiler design is the art of compromise to achieve a certain set of parameters that define the characteristics of the final design.

My "low cost foiling" proposal was submitted to provoke thought on how one could achieve a basic foiler at the lowest possible cost, recognizing that every design is the sum of it's compromises to reach the designer's targets of price, performance, durability and value.Good idea to think about it-but you have to start with a practical set of numbers that define the characteristics you want in your low cost foiler-and then see how much doing it that way will actually cost-I've done this numerous times and thats why I'm convinced something is wrong with the price estimate for the Swiss KissCut foiler.

Returning to my original point, here are the conundrums:

1) Ultra low weight and strength generally requires exotic and expensive materials. Higher cost reduces the available buyer pool.Ultra low weight is NOT necessary as proved by the all fiberglass Moth F/x, the M4, R Class, among others

2) Safe and simple operation generally requires lowering the performance bar to add stability and simplicity. Not true-as beach cats have proved since they were first introduced

3) Adding the design criteria of a "general purpose all condition sailboat" to the high performance foiling ability makes the design brief very broad. The broader the design brief, the more expensive and complex the solution. Not necessarily-careful and innovative design coupled with cost effective materials choices can produce a Peoples Foiler, beach sailable with retractable foils, reefable rig, buoyancy pods etc. It would have"low/reasonable cost, simple and safe operation, moderate to high performance and usable in the same conditions as any other dinghy.

--
Bill
================
I think that you can start with a price but you have to be realistic-is $6,000 the retail price as sold by a dealer? But whether you start with a price as you want to or with a set of characteristics as I do at some point, very early on, you have to seriously look at the numbers to see what is actually required to meet the characteristics-or the price.

[ancient kayaker]

Speaking for myself, I would not want a pure foiler, something that would be uncomfortable, expensive and quickly go out of date. I am not pursuing records and I am not interested in competition.

Maybe I've just damned myself on the eyes of some in the forum. I like boats, I like experimenting and I want to sail. Foiling looks ans ounds like a blast and I would also like to give it a try. From this, you can see that I'm not really interested in a boat such as the moth which will leap onto its foils everytime someone on the bank sneezes. I can't see myself owning a boat that will foil in a 5k wind but I certainly can see myself safely and happily sailing in 10k wind. And wondering all the time "will she foil if ..."

I can put myself in a kayak or canoe for a total weight of 200 lb or so or I can consider my nearly finished small, stout sailboat at about 260 lb.

"If you want to take off in the same wind as a Moth you need a W/SA of 2.558 or less"

-OK that's a place to start. 85 sq ft on a kayak is a bit high, 100 on the sailboat is doable although a bit of a handful and probably not enough as she is a fattie. If I double the wind that quadruples the thrust: can I reduce the sail area proportionately? I understand there are other factors such as foil performance and hull drag to consider but I am just looking for a place to start at this point. Baby steps.

I am curious about the long narrow hull shapes that seem to be prevalent on foilers. I would have though a planing shape - wide/flat- would be a better choice. Is the consideration primarly one of weight or are there other causes and effects?

[Chris Ostlind]

Very reasoned thinking, Terry. Small steps

Best you consult with experienced foiling guys like Gary Baigent who actually builds and sails the boats he loves.

Gary can get you on a planned discovery process and it won't involve many thousands of dollars to get there. Since you like to get stuff built in your shop, you'll be miles ahead of those who only spew.

If you come round to multihulls with trad, non-flying, foils... I'll be happy to help you with any questions you may have.

Whatever it is, make sure you have fun doing it.

[Doug Lord]

Terry,If you want to takeoff in around 10 knots of wind you can use a rough W/SA of 3.14. If you want a foil that just reduces wetted surface ie, "foil assist" use the formula for lift to calculate a foil area and speed that will reduce the wetted surface of the boat by approximately four times the planform area of the foils. You might want to have to have Abbots and Doenhoffs or use X-foil(ask Tom) but I've given you CI's that I've found work in practice.
A&D gets you the CI(coeficient of Lift) and you could use the 63412 foil as a representative foil. The formula seems to be accurate for aspect ratio's of around 7/1. This is for horizontal t-foils; with angled foils you can probably calculate the total area of lift from the projected area of the foil but keep in mind that because of leeway the windward foil is operating at a lower CI than the leeward foil. You can estimate this for your purposes.
The formula:
S=L/[F X V squared X CI] where

S= Area of Foil in sq.ft.
L= Total weight in pounds
F= 2.09
V squared= Speed in mph squared
Cl= ideal for 63412 foil .3 to .6 which equates to zero degrees angle of attack to approx. + 2 degrees. A good initial set up would be +1.5 degrees + full flap(if used) or start at +2 degrees-no flap. For foil assist you don't need altitude control; same for angled foils. You'll need a wand or similar for fully submerged foils.
---------------
You need to pay attention to L/B ratio or make sure that the planing hull you design is similar to the "humpless" Bethwaite skiffs. The RS600FF is an example of a planing hull dinghy that is also a high performance foiler-see the comparisons above.

[Cheesy]

================
I think that you can start with a price but you have to be realistic-is $6,000 the retail price as sold by a dealer? But whether you start with a price as you want to or with a set of characteristics as I do at some point, very early on, you have to seriously look at the numbers to see what is actually required to meet the characteristics-or the price.

Aside from the engineering difficulties, at that sort of price why would I go out and buy a (peoples)foiler when I could get set up with kite surfing kit and or wind surfing kit? For accessibility to an exciting wind powered water sport its hard to beat kite surfing at the moment, and its going to grow with course racing as well

[Doug Lord]

Aside from the engineering difficulties, at that sort of price why would I go out and buy a (peoples)foiler when I could get set up with kite surfing kit and or wind surfing kit? For accessibility to an exciting wind powered water sport its hard to beat kite surfing at the moment, and its going to grow with course racing as well

==================
My personal opinion is that a Peoples Foiler has got to be able to perform well in light air(5 knots wind) with one or two people on board-with a reefable rig, retractable foils, etc. How much is that worth?

[Cheesy]

==================
My personal opinion is that a Peoples Foiler has got to be able to perform well in light air(5 knots wind) with one or two people on board-with a reefable rig, retractable foils, etc. How much is that worth?

Where I live that would be worth very little, most sumer afternoons we get a 15kt plus sea breeze, which Im guessing would make something that foils in 5kts tricky to sail here. If I was going to make a peoples foiler it would look a bit like a Weta with Bruce foils and a T foil rudder......

[Doug Lord]

Where I live that would be worth very little, most sumer afternoons we get a 15kt plus sea breeze, which Im guessing would make something that foils in 5kts tricky to sail here. If I was going to make a peoples foiler it would look a bit like a Weta with Bruce foils and a T foil rudder......

======================
Did you miss the part about the reefable rig? I don't think you mean "bruce foils"(which are usually defined as low aspect ratio foils) but sort of a mini hydroptere? Why do you think that configuration would be better than a bi-foiler?
Here is Brett Burvills foil design for a surface piercing(SP) foiler Moth-the first Moth to win a race on foils-and banned as a "catamaran configuration" according to the class rules. Is this similar to what you had in mind?
(also good shot of hydrop foils in 2005)

[Cheesy]

Yip a mini hydroptere is pretty much what I would come up with. I did see the bit about reefable sails but from experience they dont work very well, I havent seen a rig that has good gust response with a reefed sail, the bend characteristics/luff curve of the mast usually turn to custard, have a look to see how many of the OZ/NZ sport boats have reefable rigs.... or even almost any other dinghy

[bistros]

Winds sufficient to fly a competition foiler are common enough, and "minimum foiling wind" don't tell us non-foilers an awful lot about what we would have to do to join the foiling ranks. I don't think the problem is one of power, no more power is needed to stay up on foils than to keep on planing, once the condition is achieved.

It is getting into these conditions that needs the power. Once speed starts to climb, and on certain points of sailing, the question of aerodynamic efficiency becomes an issue. But that's not needed just to have fun.

What would certainly "sell" would be a kit that could be added to an existing boat that would, conditions permitting, allow foiling. The foils could be retractable with a minimum of fuss, perhaps stored in the boat. It would be a sometime thing for most sailors, not worth a huge investment.

So what would be the minimum needed? let's assume we would like to add foils to a small boat like the Laser that's already capable of planing. Is the existing sail area and form suitable and what kind of foil area would be appropriate?

One of the best performance dinghy designers of our time just did this to the 49er. Frank Bethwaite made a bolt-on kit consisting of:
- a lateral horizontal foil between two "leeboard" like vertical foils attached to the sides of the boat - and -
- a front mounted "canard" style steerable lifting foil to enable "tractor" style front steering.

This "kit" is (theoretically) removable and the boat involved can be brought back to class legal. Frank's son Julian indicated that the project was an exercise in investigating foiling for his 70+ year old father. You aren't alone in your "highly experienced" interest.

A Laser is a tough target platform. Heavy, and underpowered.

I think it would be easiest to start with a clean slate and design a low cost foiler from scratch. I've not put a huge amount of thought into it, but my first thoughts are that a very lightweight catamaran may be a good place to start. Stable, light and fast is a good place to start. You get the very narrow fast hulls that make reaching take off speed possible.

I haven't got any built-in dislike of multihulls, and don't think a monohull is the only way to play. Occam's razor is an old friend. I bet it is possible to build a really lightweight cat without resorting to exotic materials.

A lightweight cat may be a better place to start than trying to build a skinny aka with two tiny amas and call it a monohull, labelling the amas as "buoyancy pods".

I really like Frank Bethwaite's simple "main" lifting foil on his 49er experiment, and a similar design would possibly work on a cat. Simple and it would not prevent the cat from being sailable without the lifting foils.

Not a bad place to start though ....

--
Bill

[Doug Lord]

Terry, all small cats that have been tried with foils so far have proved problematic and ,generally, not faster than their non-foiled counterparts. In a small size a trimaran configuration with fairly small amas/buoyancy pods would be the simplest especially if you went with just two foils rather than three, but a three foil system-like the Rave- would allow the foils to develop all the RM so you could just sit in the middle-it is the least athletic configuration you could come up with. It would probably require a main hull with a L/B of at least 10/1 and a square or over square overall beam-and would be close to the least weight sensitive configuration. The Rave is rotomolded and is 368+ pounds and foils singlehanded in about 10 knots of wind. A boat like this has advantages in the skipper being able to sit in the middle, simple retractable foils but requires serious engineering because the loads when the foils develop the RM are huge.
A small surface piercer would require some crew movement but not as much as a monohull foiler and a wide beam. It has advantages in not requiring an altitude control system and you could make the foils retract like Hydropteres do-folding up under the cross arm.

[Doug Lord]

Yip a mini hydroptere is pretty much what I would come up with. I did see the bit about reefable sails but from experience they dont work very well, I havent seen a rig that has good gust response with a reefed sail, the bend characteristics/luff curve of the mast usually turn to custard, have a look to see how many of the OZ/NZ sport boats have reefable rigs.... or even almost any other dinghy
---------------------------
According to Linton Jenkins of Full Force boats(that build the RS600FF) their reefing system works quite well. And don't forget Hydroptere: she has set records with her main reefed.
Check out Bradfields 18' NF cubed surface piercer here: http://sites.google.com/site/hydrosail/HydroSail-Home

[bistros]

Terry, all small cats that have been tried with foils so far have proved problematic and ,generally, not faster than their non-foiled counterparts. In a small size a trimaran configuration with fairly small amas/buoyancy pods would be the simplest especially if you went with just two foils rather than three, but a three foil system-like the Rave- would allow the foils to develop all the RM so you could just sit in the middle-it is the least athletic configuration you could come up with. It would probably require a main hull with a L/B of at least 10/1 and a square or over square overall beam-and would be close to the least weight sensitive configuration. The Rave is rotomolded and is 368+ pounds and foils singlehanded in about 10 knots of wind. A boat like this has advantages in the skipper being able to sit in the middle, simple retractable foils but requires serious engineering because the loads when the foils develop the RM are huge.
A small surface piercer would require some crew movement but not as much as a monohull foiler and a wide beam. It has advantages in not requiring an altitude control system and you could make the foils retract like Hydropteres do-folding up under the cross arm.

Doug:

Terry's interest and that of many is not to be the fastest, most complex boat on the water, and my premature thoughts are for low cost. Although the real world does not frequently intrude in your thinking process, comparing Hydroptere and the Rave to a minimal complexity, performance not-optimal low budget effort is pointless.

Both Terry and I are engineering professionals, and we both thrive on solving problems and working within a well-defined design brief. Terry lives about thirty minutes from Steve Killing, and I think solving problems with a basic foiling cat design may be possible. He's got some relevant experience available in the neighborhood. The resources are there for the asking if you show up with a coffee and good attitude. My personal goals for a project like this would not be to achieve Moth performance - I'd be happy to be able to post photos of an inexpensive garage project foiling. I'd be far happier to be sailing one.

The whole Internet-literate world is far too aware of your positions on the issues - perhaps you could let others carry on a discussion without reiterating your conclusions and grabbing at the microphone constantly. There are many ways to do things, and others may want to try.

I do applaud and congratulate your acceptance that your "designs" are effectively trimarans. It is a milestone worth praise.

Cheers,

--
Bill

[Doug Lord]

Doug:

Terry lives about thirty minutes from Steve Killing, and I think solving problems with a basic foiling cat design may be possible. He's got some relevant experience available in the neighborhood.
--
Bill
=====================
Steve Killing designed Rocker-notable for its lack of success against other C Class Cats. This is nothing against Steve Killing but only serves to point out that from the 1970's thru to now foiling cats have been poor performers-and ,generally, more complex than tri based foilers. You'd be better off just sailing a cat without foils!
There is a wide range of people that have built foilers simply that work-Doug Halsey who is a member here has built a small simple surface piercer and it is worth doing some research on www.foils.org
This is a thread about Doug Halseys surface piercing foiler and an experiment he did sailing it without the amas-it would be worthwhile for Terry to contact this guy:
http://www.boatdesign.net/forums/multihulls/taking-off-training-wheels-sailing-hydrofoil-trimaran-without-amas-23293.html

[Doug Lord]

Doug:

I do applaud and congratulate your acceptance that your "designs" are effectively trimarans. It is a milestone worth praise.

Cheers,

--
Bill

-----------------------------
Which designs? The F3 and Flyer are trimarans. The new boat I'm building is based on the boat shown in the pictures below and is not a trimaran because the amas are NOT used in normal sailing. That was(is) Bethwaites rationale on the large monohull shown in the picture below. To be a trimaran it would seem the amas need to be used as they would be on a normal tri...

[bistros]

=====================
Steve Killing designed Rocker-notable for its lack of success against other C Class Cats. This is nothing against Steve Killing but only serves to point out that from the 1970's thru to now foiling cats have been poor performers-and ,generally, more complex than tri based foilers. You'd be better off just sailing a cat without foils!
There is a wide range of people that have built foilers simply that work-Doug Halsey who is a member here has built a small simple surface piercer and it is worth doing some research on www.foils.org
This is a thread about Doug Halseys surface piercing foiler and an experiment he did sailing it without the amas-it would be worthwhile for Terry to contact this guy:
http://www.boatdesign.net/forums/multihulls/taking-off-training-wheels-sailing-hydrofoil-trimaran-without-amas-23293.html

You don't get it. Doing a project to investigate and learn more about foiling on a low/limited budget has nothing to do with how Rocker performed in comparison to Alpha. Since there is no intent to compare performance against anything, why do you persist? Fredo, Blunted and all involved learned a serious amount about foiling by actually doing it. And they succeeded in the learning exercise.

Unlike your projects, the primary goal in a project like this would be to actually achieve (verifiable) foiling while having fun. Yes, the design would most likely be faster around the cans without the lifting foils, but who cares? You learn nothing by failing to try. I think a low cost foiler would be cool, even if there were faster boats around. Personally, I cherish the time in the shop building stuff. It is relaxing.

Steve Killing also designed the world championship winning C-Class catamaran Alpha which unseated Steve Clark's venerable Cogito after many years of domination. Your characterization of his work is unfair. His work is notable and professional with many world-class winning designs.

Cheers,

--
Bill

[Doug Lord]

Yes, the design would most likely be faster around the cans without the lifting foils, but who cares?
-----------
I'm afraid YOU don't get it: there is no reason for this to be the case if a little research is done and the design is done well.

[bistros]

-----------
I'm afraid YOU don't get it: there is no reason for this to be the case if a little research is done and the design is done well.

And that is why I've built two boats while you've been surfing the net and irritating people. Research is pointless without development, and real knowledge comes from application of theory. Try, fail, fix, retry, fail is far more effective than anecdotally collecting information and drawing conclusions without ever actually trying.

Analysis paralysis is a real problem, especially when people are afraid of failure. People have to make failure their friend, and realize that failure is a better teacher than collecting other people's Internet posts. I could care less if your new project works, but I think it really matters that it get built and on the water.

You seem to have reached a lot of conclusions on what you believe is the "right" way and "only" way to do things. These conclusions are valueless without proof of concept.

Cheers,

--
Bill

[Chris Ostlind]

I'm afraid YOU don't get it: there is no reason for this to be the case if a little research is done and the design is done well.



So, Doug... just to make sure that we all have this straight. Are you now suggesting that Fredo and Killing did not do their homework and that their C-Cat foil project was poorly researched and came to sail with a lousy design?

We wait, breathlessly, for your learned response.

Further... since when do you have the temerity to challenge two, rather accomplished persons in the world of sailboat design and performance?

Your only foil equipped example to make it to the water...? It never worked, has been scrapped-out to a windsurf school and you can't seem to get the much blabbed-about latest iteration out of the garage and on the water, some three years later?

Fredo's boat got on the water faster, went through a serious comparison trial against the best C-Cats in the world and then the gentlemen flying the boat went out and captured the C-Class Catamaran World Title on another craft of their own making. All this was done, mind you, in the full view of the sailing public with photos (hundreds of them) posted everywhere in the sailing press.

Yet, here you are suggesting that they don't have a clue while you have no photos, have no working boat and no idea as to when this magnificent world beater of yours will ever actually see the water for a test.

Please, Doug, have the good sense to shut down the noise level when it comes to foiling craft until such time as you get your own boat on the water and prove that you have a degree of accomplishment that gets you into the game.... and no, the little toy boats do not count.


.

[Doug Lord]

And that is why I've built two boats while you've been surfing the net and irritating people.
Cheers,

--
Bill
======================
You don't know what you're talking about! I've given Terry of lot of info he can use in any way he wants to as well as resources to talk to people who have actually done what he wants to do. It is completely idiotic to decide for him, as you have, to build a cat which is one of the worst foiling platforms around-particularly in a small boat. You would benefit from doing research on this matter since your ideas are attempting to "reinvent the wheel" rather than using the knowledge that is freely available to come up with a first class workable, proven design rather than starting with an idea that has been PROVEN to be much less suitable for this application.
You have no idea of the implication on foiling of the beam of a cat or any of the other parameters related to building a multifoiler that a little research would reveal. You blurt out an idea laced with personal zingers directed at me without any understanding whatsoever of the ridiculousness of your comments.

[ancient kayaker]

-Chris, thanks for the encouragement, I’ll bear that in mind. I haven’t ruled out a multihull but there’s only so many hours in the day and I’m still new to this ...

-Doug: thanks for the suggestions and data. As I noted before, this fits in well with another project, it looks like it will have to wait for next year, but it's all gone into my file. I haven't ruled out a cat (am working on a small design actually) for foiling, but my studies so far indicate increased lateral stability trades with reduced longitudinal stability so I am not yet a cat person.

-Bill: the Frank Bethwaite foiler kit sounds very close to what I am working toward for my experiment, right down to the tractor steering! It's reassuring that it was intended for a 70+ year old, as I am heading into that territory soon.

I didn't want to highjack this thread and I also regret the turn that has been taken in recent posts. When I start to get serious I will resurrect one of my earlier threads on a related issue. In the meantime, thanks to all for your inputs!

[bistros]

======================
You don't know what you're talking about! I've given Terry of lot of info he can use in any way he wants to as well as resources to talk to people who have actually done what he wants to do. It is completely idiotic to decide for him, as you have, to build a cat which is one of the worst foiling platforms around-particularly in a small boat. You would benefit from doing research on this matter since your ideas are attempting to "reinvent the wheel" rather than using the knowledge that is freely available to come up with a first class workable, proven design rather than starting with an idea that has been PROVEN to be much less suitable for this application.
You have no idea of the implication on foiling of the beam of a cat or any of the other parameters related to building a multifoiler that a little research would reveal. You blurt out an idea laced with personal zingers directed at me without any understanding whatsoever of the ridiculousness of your comments.

Doug:

I'm getting tired of this conversation. What matters in a foiler is the foils which remain in the water when the boat is at speed. The hull configuration is pointless except from an aerodynamic drag point of view. Your chum Thomas Jundt proved this point conclusively sailing Mirabaud with and then without a hull. There is no such thing as a "catamaran" in play if Bethwaite-style foils are used - what matters is what is left in the water.

The (hull or) hulls are not relevant once foiling is achieved. A wide trampoline, a lightweight platform are important. Consider this concept with larger amas and no aka - its not that different, except in lowered build complexity and higher initial stability. Using a Bethwaite style lifting foil reduces and eliminates a lot of centerline structure and divides the vertical lifting foil loading to two attachment points instead of one - far easier to build. Now think about a Tomahawk style foil where there is no need for wands.

It may be you that has to rethink your preconceptions.

Cheers,

--
Bill

[Doug Lord]

Terry, this cat is the most innovative foiling cat I've ever seen. Take some time and look at it closely. All full flying cats before this have used three to four hydrofoils-this thing breaks the mold by using only two mounted in a center module that slides from side to side. It can be configured from "foil assist" to full flying . Note how the foils retract. Here is a bunch of information for you:
http://www.youtube.com/watch?v=ZggxS6ZrVOw

http://cid-7e32cd25ce4f4c84.skydrive.live.com/browse.aspx/happy%20feet

designer is natthavarat titapan --- nat-dezine@live.com

http://sailingthailand.ning.com/profiles/blog/list?user=2h129b4137pja
---------------
This boat is just one more thing to consider. I think that a trimaran configuration with either fully submerged foils ,surface piercing foils or a bi-foil config may be much simpler for a small boat.....

[bistros]

Terry, this cat is the most innovative foiling cat I've ever seen. Take some time and look at it closely. All full flying cats before this have used three to four hydrofoils-this thing breaks the mold by using only two mounted in a center module that slides from side to side. It can be configured from "foil assist" to full flying . Note how the foils retract. Here is a bunch of information for you:
http://www.youtube.com/watch?v=ZggxS6ZrVOw

http://cid-7e32cd25ce4f4c84.skydrive.live.com/browse.aspx/happy%20feet

designer is natthavarat titapan --- nat-dezine@live.com

http://sailingthailand.ning.com/profiles/blog/list?user=2h129b4137pja

Interesting design. It looks far more complicated and on a far larger scale than what I proposed, but it does have a similar two foil configuration my proposed design does. It provides a little confirmation that my concept may not be as poor as one reviewer thinks!

This one is a little too expensive to be a garage project!

Cheers,

--
Bill

[ancient kayaker]

Interesting craft! I was particularly taken by the biplane rig; theoretically it is advantageous on many points and even straight downwind it can be goosewinged readily. yet another thing I want to fool around with someday. Looks like they are having problems with the longitudinal stability that my own studies have indicated.

[Chris Ostlind]

... It provides...confirmation that my concept may not be as poor as one reviewer thinks!

This one is a little too expensive to be a garage project!




Yes, that one is out of reach for the typical garage, but your take, Bill, has real merit.

I'd be grateful to have an involvement in a project, such as the one you propose. We will get it on the water and sailing, well before any Futz-Foil design by other, long threatening party's and won't that be a total wipe-out scoop on the playing field?

[Doug Lord]

Well, that would be terrific-two of the most anti-foiler individuals on boatdesign.net and sailing anarchy finally swing the other way and build their own foiler! Wow-I think that's great-great for foiling and a great benchmark.
Best of luck-go for it!

[Chris Ostlind]

Get this, Dougie and get it good.

Whatever we do, it has nothing to do with you. It will prove that a proper boat can be designed, built and successfully trialed in a very short period of time... should the people involved put themselves on the task, rather than some kind of weird, monkey dance, such as we have seen from you over the past four years.

For me, it's not even about foiling for foiling's sake. It's about exploring design potentials within the vast sphere of small craft. It's intriguing to me because it gives the readers of my site an opportunity to wander about the landscape a bit, sampling ideas as they go. Something along the lines of a huge, small boat buffet, where all the bits are tasty and more than a bit provocative.

As to your purposes, Doug, well...

[Doug Lord]

Sure, Mr. Ostlind-I understand perfectly. Best of luck on your new venture!

[ancient kayaker]

...For me, it's not even about foiling for foiling's sake. It's about exploring design potentials within the vast sphere of small craft...

For me, definitely the highlight of that post.

[bistros]

Well, that would be terrific-two of the most anti-foiler individuals on boatdesign.net and sailing anarchy finally swing the other way and build their own foiler! Wow-I think that's great-great for foiling and a great benchmark.
Best of luck-go for it!

Thanks for the vote of confidence. I'm actually not "anti-foiling" at all - I'm potentially interested in making it happen within a very limited budget. I think creating an affordable homebuild foiler would be interesting.

I do have a long standing professional distaste for moving target product specifications, poor product planning, failed execution, over promotion and I absolutely hate unnecessary complexity. My difficulty with these issues is in direct conflict with some of the projects talked about here.

I've got to get Thomas' boat completed, and then I'll see how bad the boat building bug bites me. Hypothetically, it won't be hard to start the process this winter of defining a serious design brief, finding and building a team and perhaps building a little community support to help the project become real. I think you (Doug) have provided an excess of publicity for an affordable foiler - maybe someone should actually make one!

Cheers,

--
Bill

[Doug Lord]

I think you (Doug) have provided an excess of publicity for an affordable foiler - maybe someone should actually make one!

Cheers,

--
Bill
=======================
Good Luck!

[bgulari]

The moth in the center of the happy feet does not move to windward or leeward.

start using 180 lbs in you moth figures doug

[Doug Lord]

The moth in the center of the happy feet does not move to windward or leeward.

start using 180 lbs in you moth figures doug
---------------------------
The module with the two hydrofoils does move side to side-it is one of the important design features of the boat.

http://sailingthailand.ning.com/profiles/blogs/happy-foot-breaks-leg


" plans for sunday, may 3, were "foiled" by saturdays accident. sailing in gusty westerly's, we had the pod to leeward for the first time and it was feeling quite good, thinking we could get the whole boat up. a gust came through but as the windward hull was lifting the cb broke clean away with a very loud bang. it made a nasty gash along the port hull bottom as it went past. repairs are underway but won't be finished for the club race on the 17th.

this boat is an ambitious development project with little precedent to draw from. i am satisfied with our success so far but setbacks can still be expected. obviously i will make everything stronger but also refine some of the mechanisms. the new lift foil will be asymmetric and have a greater range of flap angle. the sails have been re-cut and the rig is being re-evaluated to better control sail shape. "

[ancient kayaker]

I’ve been following this thread for a while with considerable interest. I hope it will not peter out, although all good things must end. I gathered Kisskut was intended as a kind of peoples’ foiler although the Swiss may have a rosy concept of what average people are prepared to pay.

My own thoughts on the peoples’ foiler continue to mature. It was frustrating for me to lose a year as I hoped to get 2 pre-foiling sailing platforms into the water this year and ended with nothing actually wet, best laid plans etc. However a couple of finished hulls are clogging the workshop awaiting rigs; health permitting my Summer of discontent will be made Glorious Winter by rig-building unparalleled ... er, I better take my medication ...

I suspect if the peoples’ foiler is to happen it might be as a plan or kit, perhaps a retrofit kit for suitable existing sailboats. That is the route I am taking presently, hence the “pre-foiling” in the previous para.

I don’t much fancy manual attitude control or auto control come to that, much prefer built-in stability for simplicity. IMHO it’s not the speed it’s the impression of it that will sell, like those noisy exhaust kits for Harleys. Foilers are still as common as hens teeth in my neck of the woods, but if I can fly one past the local marina on a race day who knows where it will lead ...

I think a previously-mentioned mini-hydroptere config has merit; I imagine a simple outrigger arrangement with very small amas flown clear of the water when foiling, like training wheels, with steerable surface piercing foils acting like Bruce foils to balance heeling moment, to be removable from a basic mono hull for those folk who believe in life after foiling. Not sure what should hold the stern up at this point though, probably a Tee foil. I may let the stern just drag initially, to see if that leads to the forward foils ventilating or stalling. Sail thrust may reduce weight on the stern somewhat. We’ll see.

My experience carving a daggerboard for my recently completed little sailboat with an accurate profile has given me some insight into what will be involved in making the foils. I probably didn’t need such an accurate profile, according to the designer, but he didn’t know I had an ulterior motive ... now I know I can produce the profile of my choice.

Before evolving to a foiler I must adapt from a longtime paddler to a sailor; at least I now have the means! I can try various rigs on the sailboat and also sails on some of my long-suffering kayaks and canoes. There are biplane rigs, lateens and wing sails to explore as well as more research into Bruce foils and derivatives.

By the way Bill, I haven’t forgotten you suggested contacting Steve Killing. Pioneers always face the biggest challenge and I personally have found I learn from my mistakes and merely confirm my theories with my successes, but I have no objection to learning from others!

[Doug Lord]

Terry, you might gain something by reading Tom Speers "Foiler Design" here-and don't forget Vellingas book-it is a must have for anyone experimenting with foils.
Have fun and good luck.....

[ancient kayaker]

I took another look at the foiler in post #31, after reading the following comments on it, which revealed what I had missed. The central module bears the foils and is moved laterally for balancing, as shown clearly in the picture in post 42.

Innovative yes, but it seems almost shockingly weird. The mechanical and control challenges must be formidable, especially in full-foiling mode. It is hard to believe that someone would go as far as to build such a coffee shop concept.

Does it have any advantage over movable ballast? The masts are vertical so there is no vectored thrust advantage in moving those with respect to the foils as well as the ballast. Why would anyone bother? It seems to me it would have been simpler to move the bridge and amas with respect to everything else, which could also be implemented in a retrofit foiling kit for an existing mono, but of course the biplane rig would have to go.

Keep up the good work, Doug! I am not even going to even think about incorporating this concept into any design of mine, but as an exercise in thinking outside of the box, it is mind-blowing.

[Doug Lord]

Thanks Terry, it is a very innovative solution to the idea of using hydrofoils on a cat.
To the best of my knowledge it is the first cat to use fewer than three foils and is significant for that reason alone. But it has tremendous potential especially in "foil assist" where the foils don't necessarily lift the whole boat clear of the water-but significantly reduces drag. I don't know the details of how Arnie and the designer have made the center module work but if it actually works smoothly and is not too heavy I think the
system is quite an advance. The ability to fully retract the foils is really a good by-product of the system. With the module over to one side the RM of the boat is substantial and Arnie says it has flown 100% in that configuration.

[ancient kayaker]

I'm not so sure: if the cemter module is light moving it will have little effect on RM; easier to move the meat.

[Doug Lord]

I'm not so sure: if the cemter module is light moving it will have little effect on RM; easier to move the meat.
--------------
Terry, the reason the center module can have a large effect on RM is that by moving it to leeward the center of lift of the foils becomes quite separated from the boats CG creating a righting arm and -if the boat flies a fairly large RM. The crew in the weather hull adds to it as you point out.
If the boat was to 100% fly with the module centered there would be zero righting moment created by the weight of the boat-the only RM in that case would be that created by the distance to weather the crew is from the center of lift of the foils.
One of the foil assist options is to leave the module centered and set the adjustable wand for an altitude that reflects the windward hull just clearing the water. According to Arnie this set up gets the thing to fly the windward hull before it would normally AND the wand will cause the foils to pull down as well as up- adding to RM if the wind increases and maintaining the boat at a set angle of heel. The foils pull down or up depending on wind strength.
--
There is more to this thing than meets the eye at first glance.....

[bistros]

--------------
Terry, the reason the center module can have a large effect on RM is that by moving it to leeward the center of lift of the foils becomes quite separated from the boats CG creating a righting arm and -if the boat flies a fairly large RM. The crew in the weather hull adds to it as you point out.
If the boat was to 100% fly with the module centered there would be zero righting moment created by the weight of the boat-the only RM in that case would be that created by the distance to weather the crew is from the center of lift of the foils.
One of the foil assist options is to leave the module centered and set the adjustable wand for an altitude that reflects the windward hull just clearing the water. According to Arnie this set up gets the thing to fly the windward hull before it would normally AND the wand will cause the foils to pull down as well as up- adding to RM if the wind increases and maintaining the boat at a set angle of heel. The foils pull down or up depending on wind strength.
--
There is more to this thing than meets the eye at first glance.....

And it broke catastrophically the first time he tried to lift both hulls out of the water with the module to leeward. These aren't trival forces you are playing with, and the stiction in loaded system of this type has got to be huge.

I know that some folks are absolutely in love with complex solutions to simple problems, but Terry's reference to moving the meat is the simplest solution. There's more to meat than the first glance of your eye.

--
Bill

[Doug Lord]

From Arnie Duckworth:

"this boat is an ambitious development project with little precedent to draw from. i am satisfied with our success so far but setbacks can still be expected. obviously i will make everything stronger but also refine some of the mechanisms. the new lift foil will be asymmetric and have a greater range of flap angle. the sails have been re-cut and the rig is being re-evaluated to better control sail shape. "
----------
Whether the foils were fixed in the center or on the movable module to leeward the crew would have to move. The problem is with the foils fixed in the center position the weight of the boat does not contribute to RM. With the sliding module the weight of the boat contributes to RM as in a "normal" cat. The center position is an excellent "foil assist" configuration but the highest performance will be with the module as far to leeward as possible.

[Gary Baigent]

Yes, the system theoretically could work (and I would be the last to damn an original project because of breakages) - but surely there is a simpler way to lift a catamaran .... like angled foils through the hulls. But at the moment: "Okay, we've lee foiled our way into the lead, let's tack, crank that foil assembly across to the middle, you blokes, or what about the windward side? it will be better there on the next board, mumble, mumble, decision, grind, grind, heavens! the loads are high and now it's jammed and the whole fleet has passed us by - and we're stuck in irons with the foil in the platform middle. Hey, that foil assembly has got real weighty with all the epoxy and carbon reinforcements, Arnie, you sure you didn't use polyester resin?."

[Doug Lord]

Yes, the system theoretically could work (and I would be the last to damn an original project because of breakages) - but surely there is a simpler way to lift a catamaran .... like angled foils through the hulls. ."

=============
Simpler yes. With as wide an effective range for full flying and foil assist, no.
Unless ,of course, you've got it ,Gary?
There is no theoretically about it-the system works!
* easily retracted foils
* easily moved module
* multiple configurations available from foil assist to full flying-no other full flying cat configuration even comes close to this.
* 33% less foils than any other full flying catamaran

[ancient kayaker]

Agreed, it is a fascinating, even audacious concept, but it still doesn't blow my skirt up!

[Doug Lord]

Agreed, it is a fascinating, even audacious concept, but it still doesn't blow my skirt up!

===================
What-you don't wear a mini skirt?? Ok, nevermind......

[Gary Baigent]

Doug, my man, what is a wide and effective range for full flying and foil assist? All foilers are in that state, blows a bit harder, flying, quieter winds, foil assist. Easily retracted foils, same again. Easy module shift, not so sure about that, mate, underway I mean. 33% less foil area, sounds a bit BS too. Also you're forgetting module drag in a seaway. How about weights with this complexity? All power to Arnie and his designer ... but I'm for simplicity.

[BWD]

um tink e meant a say 33% less number of foils. ;)

PS kinda OT but: Luderitz update No.1 Vm 61.7 500m 53
and they only getting warmed up :P (tease tease...)

[Gary Baigent]

You are correct BWD, my misreading - but I still question the 33% figure - cat with conventional angled foils, leeward foil down, windward one up, plus rudder equals 2 foils immersed, the same as my foiler tri Flash Harry - I mean that's no more than a conventional monohull.

[bistros]

=============
Simpler yes. With as wide an effective range for full flying and foil assist, no.


I'd agree with this in theory. Not having witnessed it I could not reach a conclusion however. The design brief certainly has a wide and effective range. Not sure about the boat - this is the Internet after all.


Unless ,of course, you've got it ,Gary?
There is no theoretically about it-the system works!


Did you see this? Have you got pictures of the boat fully foiling? Didn't think so.



* easily retracted foils
* easily moved module
* multiple configurations available from foil assist to full flying-no other full flying cat configuration even comes close to this.
* 33% less foils than any other full flying catamaran

We don't know if the items Doug specifies as "easily" handled are - all we have is Internet reports to that effect, plus Doug's enthusiasm and rah-rah sis-boom-bah cheerleading. I can see how these items may be "easy" to move while under no load, but a loaded system with off axis loads due to a variety of different stressors is a different situation entirely. Lifting a loaded daggerboard while in motion is somewhat harder than doing so in a motionless boat at the dock.

This is an interesting experimental platform that shows a lot of innovation and novel approaches to the issues. Mr. Duckworth is quite honest in his assessment of it as an ongoing development project which is not complete. He seems far less content to claim complete success than Doug, although he is working towards his goals. I wish him the best!

--
Bill

[ancient kayaker]

Bill: Good point about the Internet but my feeling is, it's real. I too have reservations about moving the center pod when supporting the weight of the boat under the dynamic conditions of foiling, I would expect mechanism design challenges, much physical work and probably control difficulty.

On the other hand, it would be relatively easy to move the pod with the boat either stationary or with foils raised. That would allow the mechanism to be much lighter, and a simple clamping arrangement could handle the forces on it when foiling.

For a straight course, constant wind and other conditions the pod's position could be preset as a coarse control, with the crew’s weight providing fine adjustment. Not very practical for general purpose sailing perhaps, but for straight-line speed, or occasional foiling, an acceptable compromise.

I have not been able to determine which of the above is the case so I emailed the designer and asked him what he intended.

[Doug Lord]

There is video of the boat flying from onboard. It is part of or accessible from the url's I already posted.
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Gary, comparing this boat to your boat: you carry around four foils-this thing just two. No catamaran having a total of just two foils has ever been produced before-to the best of my knowledge. And Gary no current catamaran has the facillity to control the angle of heel in light to heavy air automatically as does Happy Feet. No current catamaran has the abiility to 100% fly on just two foils(with only two foils on the boat) That is a wider range of foil assist and full foiling than any other current catamaran. I'm fairly sure that Kotaro Horiuchi did the first tri designed to be able to 100% fly on just two foils.

PS- one other thing Gary-the Decision 35 cats the Swiss (and others I guess) race have a fixed module down the centerline of the boat-no problem with water impact that I've heard.

[Gary Baigent]

Harry has only three foils, two immersed, windward one flying clear - but yes, I'm changing to a total of four, three immersed, finished shaping the dagger this morning. But that is by the by, the point about Happy Feet's shifting module to weather in light airs (to lift windward hull somewhat) is definitely a plus for the usual sticky catamaran configuration. Good idea. In heavier breeze, module to leeward and gaining righting moment from crew and hull to windward, also good stuff. But, for a little extra complexity in conventional angled foils through hulls, why not have foil cases that can alter angle of attack through, say 12 or so degrees? Then you could lift windward hull in quiet winds too, heavier breeze as per normal angles of incidence. Has been done before on F40"s like Biscuits Cantreau - and a way, way simpler system than Arnie's sliding foil module. Eh? But yes, three foils - but so what?

[Doug Lord]

Harry has only three foils, two immersed, windward one flying clear - but yes, I'm changing to a total of four, three immersed, finished shaping the dagger this morning. But that is by the by, the point about Happy Feet's shifting module to weather in light airs (to lift windward hull somewhat) is definitely a plus for the usual sticky catamaran configuration. Good idea. In heavier breeze, module to leeward and gaining righting moment from crew and hull to windward, also good stuff. But, for a little extra complexity in conventional angled foils through hulls, why not have foil cases that can alter angle of attack through, say 12 or so degrees? Then you could lift windward hull in quiet winds too, heavier breeze as per normal angles of incidence. Has been done before on F40"s like Biscuits Cantreau - and a way, way simpler system than Arnie's sliding foil module. Eh? But yes, three foils - but so what?
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Sounds complex-but worth thinking about for some applications. Well, lets see if I remember my basic math: 3 is 1 more than two,right? Thats a 50% gain in weight and maybe drag for no gain in performance compared to two foils. So I guess 2+1=(-3) -in this particular case only......right???! Huh?
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Oh yeah and then there's this: http://www.boatdesign.net/forums/multihulls/veal-heel-multihull-foilers-28372-3.html#post311238

[Gary Baigent]

No, wrong Doug - comparing Arnie's module hard up against the leeward, or windward inwhale (and the foil is central in the module, so it is still placed, say, 300 mm towards platform centre) to an angled foil set through the hull bottom, what is that? another 400mm wider foil base, that equals much greater leverage affect, okay? Also you can't talk about weight difference between an extra foil or two plus cases to the sliding Happy Feet module - which has to much heavier.

[Doug Lord]

No, wrong Doug - comparing Arnie's module hard up against the leeward, or windward inwhale (and the foil is central in the module, so it is still placed, say, 300 mm towards platform centre) to an angled foil set through the hull bottom, what is that? another 400mm wider foil base, that equals much greater leverage affect, okay? Also you can't talk about weight difference between an extra foil or two plus cases to the sliding Happy Feet module - which has to much heavier.

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Doesn't hurt the Decision 35 much and I'll have to agree to disagree on the other. The two foils are significantly less drag.....

[Chris Ostlind]

No, wrong Doug - comparing Arnie's module ...




Uhhhh, best of luck there, Gary. When someone is dead set on forcing a square peg into a round hole, best to let them go at it with their toy hammer and keep your distance.

The one that I marvel at is the obvious juxtaposition of the Swiss thing with the Japanese thing. One one, the thingies out on the ends of the sticks are buoyancy pods and on the other, they are part of a trimaran.

Very funny stuff with fabulously adaptable nebulous nomenclature that can be swapped at will to suit the needs of the speaker.