So --who is going to propose the new FORMULA 20 class with foils --via America's Cup class.

Yes -I know -there already exists the C Class --C14 but at 25 ft 14 ft beam etc it is too impractical and large for most.
A C class campaign is very expencive --bottom line.

Unlike the AM Cup and other formula rules I would like to see the foils allowed beyond the Max beam limit --I believe if the foils were allowed to angle outward they might be reconfigured to function in upwind and downwind mode foiling .

The 72 fters are incredible cats --wow--.very inspiring.

foils outside the max beam sound relatively dangerous, both for crew retrieval as well as boat/boat crossings (starts, roundings, etc)...

The solution would be to limit the angle to say 22 degrees max from 90 degrees of hull at rest in water.That equates roughly to a little over a foot from outside edge of hull at 4 ft depth.

The shape of the foils may take on T or evan H shape variations so--RULES might allow 2 ft from hull at max 4 ft depth i e.

The other coresponding rule might be to maintain trailering width on the basic platform but allow wings or hiking racks to extend beyond --say 4 ft each side --which would be 2 ft further out than foils.

I don't believe anyone can regulate a perfect world or perfectly safe world --unless you want everyone wrapped in bubble wrap and strapped in to the crossbeam with 4 point harness and life jackets with built in airbags --etc etc etc--heaven help us if that becomes the mentality in this sport.

screw them... I was worried I'd chip a foil if I brushed up against them...

Hey, you scratched my anchor!

Build it.

out of curiosity, how do you start in a crowded line with a bunch of H-18/wings? Or F-18 skiffs / 49ers for that matter? Do the wings get all tangled up?

Naples is such a nice area --you are fortunate to have such a beautifull area to sail, lived there several decades ago --

I raced Hobie 21s way back when--they had elevated hiking racks and spin set up, you sheeted the kite off the hiking rack which made for better sheeting angle and open slot--funny though--if you forgot to tie in the hiking racks the spin would pull them right out of their hull insert and you would have a rack flyng around in the air at the end of the spin sheet. The hiking racks were not a problem and actually very nice to trap off being higher and further out from the hull --less spray and better visuals.

Noticed Morelli Melvin design already offering a 45 ft foiling cat on their website for club racing--interesting.

'build it" "and they will come"

-- from Feild of Dreams ;]

They have done just that with the Am Cup --AMAZING SHOW !

The Am Cup certainly has inspired many people.

Wing sails are not practical yet --though it is a matter of time before someone builds a foldable -raise -lower version.

Stability is the problem with foils --the crews work very hard maintaing it on the Cup cats. So --the need for a more stable simpler version is needed --perhaps angled outward ?

The INSTABILITY of 2 T foils on previous C Class cat design in example.

Perhaps 2 smaller foils on each hull for and aft for balance --not sure if a trim tab would be needed aft or not.It would be great fun building and experimenting though.

Thanks so much -recall reading the paper --They concluded "Although she flew well, was very
controllable, and was spectacular to watch, Rocker could
not match the 20 knot plus speed of Alpha."

Rocker being the T foil cat design. Alpha entually winning the C Class cup.

What we are seeing in the Am Cup are radius U L or V shaped foils. The radius boards provide lateral resistance to track to windward and lift downwind at higher speed and powered up wingsail. The cup cats control the angle of attack of the foils for and aft with hydrolics for foiling platform stability though occationally falling off the foils during mark roundings.

Seems the L or V shape foil approach enabled solutions the T foil approach could not achieve

Perhaps some experimentation is warrented with self adjusting angled foils called surface piecing foils --the higher drag comparatively of this type might be offset by the potential abilty to foil upwind --the angled foils providing sufficient lateral resistance--It might be a matter of geting the ideal balance of angle -area-and lift vs drag.

C Class "petite coupe" foiler

http://www.youtube.com/watch?v=XqagoX7HefA

That video has been out for a while now. At least 2 C-Class teams are foiling. Unknown is Steve Clarke's foil package, Team Invictus' foil package, and the Portugese foil package, though I suspect the last 2 are non-foiling and Steve is probably semi-foiling. The Canadians are playing it close to their chest but have L-foils, with the intent to be a surface skimmer. This will all be very exciting to watch.

I am of the belief that you need a big, lightweight platform with lots of efficient power. Wider is better, longer is more pitch stable etc. Just because it works on an AC72 doesn't mean it works on a C-Class, and is even less likely to work on a 20 footer. Even if it does pan out, all successful attempts I've seen require world class sailing to master. Bringing this to the masses might require another revolution in the area of waterproof electronics.

The A Class cats at 18 ft Length with 7.5 beam seem to foil well.

Sail area to length ratios are a key componant .150 sq ft on an A is proportionately easier to stabalize as is 300 on a 25 ft 14 ft beam C Class cat --20s would be somewhere in between with similar performance and 2 crew --but more practical and affordable than a C Class cat .

Given how many enjoyed the Trifoiler The Rave foiler and others it would seem foilers take no unusual skill.

20s were historically the B Class cat --The Tornado design dominated that category for decades
You are correct --a few need to build foiling 20s then build a racing class around it--the CF 20s with radius boards are close already --they need board mods to the L foiling shape and rudder redesign.They aren't far off now and surface foil.

Given the foiling mode being predominant for speed I think hull design -rig design -and foils themselves will continue to be refined to complement foiling speeds --Hulls no longer need to go THROUGH the water but should sit on top moreso --Bows in particular need to resist nose dives as they fall off foiling mode . The sail plan itself should be more oriented to help provide verticle lift --.

Funny -how basic human behaviors have not really changed much over time --there will always, ALWAYS be a portion that say in essence ---hey --we have perfectly good sticks to drag along the ground with mastadon skins stretched across to carry food --why would we need that round wheely thing attached to it ?

have fun
enjoyed the hypotheticals Sam
best regards
Carl

Carl,

I certainly think this has the ability to revolutionize the 20' class. Unfortunately, I'm not sure who is left to afford such a project. I know it's getting tougher to justify the price of a new F18 when said boat costs more than the average price of the SUV used to tow it, and we haven't yet been able to tap into the J/70 market.

The A-cat's aren't flying around the course. Semi-foiling downwind yes, but no one has course raced a full-flying A. I think the box rules there are too limiting, but even more so is you only have 1 person to handle boards etc.

The other development is relatively easy to be honest, windsurfers have been traveling at >30 kts for many decades, as have the Moths for approaching a decade. Plenty of CFD for hull shape analysis, and intellectual know-how on that front.

I might come across as the anti-foiler but that is far from the case. I think an affordable, $20K 2 person foiling beach cat has huge market appeal. When PSA wants $5800 for the foiling kit for a laser...not sure it's doable

Just joking a bit with the wheel annalogy --as they say -no worries mate .

The A C cats foiling downwind is a spectacular show as will be the C CLASS CAT CHAMPIONSHIP NEXT WEEK .Should be fun to see --wish I were there racing --as most of us do .

I know 'I,m ever the optimictic type but it seems logical that a B Class / 20 Class gets going again too --preferably on foils ;]

Costs are always an issue --wish there were someway to make it affordable again ---I recall buying new H -18s in the 1980s for around 2 k and commonly having 50 boat fleet starts to race in . Good times !



have fun
Carl

how would you make a foiling cat "beach-able"? it looks like current foil (not C-shape) designs all have foils inserted from under the boat (unlike daggarboards), so even pulling them up will expose some part(s) of the foil to potential contact with said beach...

might make putting boat on beach wheels a bit more challenging, too...?

And would this market be limited to more of the experienced racing sailors, or do you think foiling technology could eventually be idiot-proof? A relative novice can get on a F-18 today and sail it (not be competitive). Could they do the same on a foiling boat with rudimentary knowledge of sailing?

By beach cat, I mean 2-hulled 16-20' boat. No, I don't think you'll see this winning Tybee anytime soon. Beach wheels is a question for the C-class guys, as is how they insert their foils.

Relatively idiot proof? Maybe, I don't see breaking foils every time you flip. Spending a lot of time swimming? Absolutely.

the moth guys have figured out the foiling part, but it sure isn't idiot-proof... or cheap

Good questions --as with anything new I suspect new coresponding ideas and techiques will emerge--just like we saw with Oracle --WOW what a show --eh ?.

Think you may have answered your own question on foils and beach wheels -the technique would be to wheel out to 1 ft water depth then slide it off --just as many do currently to save the hull bottoms .

Given the Trifoiler tri by Hobie and other foilers --see you tube clips of them } -they appear to be very easy to sail and very stable .

I,m wondering if someone hasn't already taken a CF 20 with radius boards that surface foil and added on a foil like A C boats and modified the rudder .

I hear that Morelli Melvin has already designed a fully foiling kit for the F20c. This has been reported by Surf City. See pics: http://www.nacra.ca/f20cfoiling-3.jpg
Foils built by team new zealand.. Design paid for by Philippe Kahn http://www.pegasus.com/log/


Does anyone have more info on this? Perhaps they could be persuaded to sell it as an upgrade kit?

looks like it has a belt (screecher) and suspenders (spinnaker)

Why do the boards flair outward at the top?

boards flare outward at the top so that upwind the board is vertical if all the way down.

http://www.nacra.ca/f20cfoiling-3.jpg

Wow --Looks like they added about 20 to 24 inches of horizontal area to the curved boards and the T foil rudder is visable in the pic.

Wondering what locks the boards in the down position --amazingly strong boards -cases -etc able to carry all the loads .

Don't believe this version would be adjustable --that is able to adjust the foil board angle like A C cats .

Trunks must be different than stock to handle the S board vs. C-board, so yes AoA etc. can be made an option.

As an upgrade kit this makes little sense with the Flying Phantom costing the same as a new Nacra F20c. Add a $5K+ foiling package to the F20c and its $5K more than a boat designed from the ground up to foil. Pegasus didn't have the Flying Phantom option when these were built, and I suspect picked up the F20c at a bargain basement price.

it's more the other way around, the Flying Phantom is a widened F18 [full displacement boat] while the F20C was designed with the curved foils to create semi foiling sailing as standard feature, so optimized to dip back en forth in the water

Has anyone developed an easy method of controling the foiling height ---that is --stabalizing the foiling above water level.

The cup cats used for and aft adjusters --moths use trim tabs .


The tendancy to "dip back en forth in the water" seems like the unwanted characteristic to correct or find a simple solution for .

Higher angles are needed to foil in light winds --once up foiling it seems a lesser angle relative to the hull is needed for optimum speed .

ETNZ did a lot of hull optimization; their initial hull shape, done without full-flying VPP analysis, was found perfectly optimized for full flying when they got the VPP working. This hull shape happens to mirror the Cirrus R pretty closely in rocker and volume. So, I would take the full flying Phantom over modifying a F20c. The F20c is designed to use the hull+foil to get into a semi-planning mode, so it is perhaps a little flatter further aft than ideal. Really the hull shape does not matter much, save enough bow volume to avoid a total wipeout and reducing drag when you're in displacement mode. Difference is the F20c doesn't come stock with board trunks that handle full flying.

Actually it does when you're trying to get the boat going fast enough to get it up on the foils.

The f20c is a better platform to foil because it has a more powerful rig. Getting up on the foils takes power. Trunks can be changed out..and there are already a bunch out there..

Yes, hulls matter when getting up, but again those shapes have already mostly been optimized with the fat sterns and modern rocker profiles.

The flying phantom has 10' carbon beams, >32' carbon rig and full carbon hulls, built by the #1 F18 builder for quality in the world. It is equally as powerful as the F20C and the build quality is likely better (read: stiffer=faster on foils). Again, I'd take the flying phantom over a full-foiling F20C in anything above about 8 kts of breeze.

Yes, the F20C is a good retrofitting platform, but again a lot of work and $10K to add foils to a boat that is just as expensive as the flying phantom to begin with. It doesn't make economic sense unless you find a F20C for less than $20K.

Had some health issues --so --have been out of the loop for a while --just catching up .

Some thoughts on foil design and configurations.

,In other words -design idea B S ing ;]

Some class rules prohibit boards or foils outside hull beam ,as result boards and foils have been designed inward from the hulls --the c shapes S shapes L shapes of lifting foils are inward from hull beam .

In proposing a 20 class it might be advantagous to allow them outside hull beam .

In example -With canted hulls the foils could follow the hull line cant below the waterline and angle outward in a T shape--or -- Another very different option would be an inverted Pi symbol type configuration from the hull . Two smaller paralell boards with a base lifting foil in each hull .

Not sure if I,ll "built it " my thoughts currently are to build a 32 ft cruising cat --but what fun it would be as a foiler when the wind kicked in .

have fun .

Carl

I'm sure foils extending past the max beam is more efficient, but dang that's got to be tricky at a crowded starting line or turn buoy.

Sort of like a bunch of H-18 with wing racks all going at it... except you can't see the foils nearly as well...

Brainstorming...slightly canted straight boards (~6°) with L's at the bottom...no curves. "Simple", easy to build, 3 part mold. Insert from bottom. Remove L-foils for beach races, insert regular straight boards from top.

Or build a set of c-boards and t-foil rudders for 98% lift and potentially less drag when it goes light.