60'+ or - 20' Ocean Racing Monofoiler Design Discussion

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Antoine, perhaps you missed this? It's essential that the 60 footer does not resemble a trimaran
since it is ,in fact, a monohull. This is an absolute tenet of my proposed 60' monofoiler.

 

have you considered how you could use the rig to improve stability? like a sailboard. windward cant can help the foils with the lifting. back and forward to control nosediving even? being able to move the mast step may also help.. like make the canted rig lift from the leeward side..

as for the balast, the smaller the better right?
what about a carbon strut that can slide from side to side like the racks on a IC. like 60" long. this strut could house your balast tanks on the ends and could also be a foil shape and incorporate flaps, to create downforce out of thin air! this would be much easier to get rid of if you were falling over to windward, or to get more of if you were getting blown down to leeward.

i think the simplest and most pure sollution would be the most successful. one foil in the water, one foil in the air vertically, one foil in the air horizontally. and probly some sort of stabilizer, whether that be an air tilplane or a water t-foil. probably be like flying a F-18. ha.

also theres no reason you couldnt use surface piercing hydroptere esque foils, in a pair, just close together. [EDIT] this would provide the benefit of self-levelling flight and possibly better stability without wrecking your monohull purity. as long as they stuck out from the hull and kicked back in. they could even be hydraulicly inclined to give it some extra righting moment maybe and shed a few more kilos of balast.

hey what if the keel extended down from your pods, so that the bulb could be extended outboard of the wing when sailing normally! in the air, not the water where its a bit buoyant and less effective. maybe have one keel strut on each side, that could like pass the bulb to one another? or just have two canting keels, one from each pod, the leeward one swings inboard, the windward one swings outboard? the leeward keel could then be your inclined hydrofoil that lifts the boat.

still i dont like the idea of hydrofoils lifting lead. why not make your mast really buoyant and big so that the boat self rights as long as the mast is on? not much use being upright with no mast anyway... with your buoyant pods, there will be no coming back from turtle anyway, no matter how big your canting keel is.

theres my 2 cents, my apologies if some of this has already been mentioned.

[edit]: that industrial designer linked on the last page i just read tried to do that. im by no means saying that that could provide all the righting moment, but may help. also he hasnt allowed them to hinge independently, to optimise the vectors.

 

Ballast

Whats the difference if some of the ballast is lead and some is water? The boat that may be fastest sailboat in the world-Hydroptere uses movable water ballast-up to 1760lbs in each ama and an undisclosed amount in the main hull.
Spitfire-a 40' Aussie surface piercer-used ballast as well. The designer said he used ballast because you only lift it once. If you're not just lugging it around and make it work then ballast -of whatever type-can be a real good thing on a high speed boat....

 

i guess im just saying you need to cull any inefficient balast, im not disputing balast in general. there are other ways to right a boat from a capsize, for instance, than to have a canting keel. also a canting keel will be inefficient at generating righting moment compared to your water-ballasted pods. with todays setup you can't get a keel to cant more than about 50 degrees, just due to the geometry of the hull and rams etc, unless you rethink the whole concept.

every kilo on board structure balast people has to be lifted by a foil, the more weight the more foil area the more drag the lower the takeoff speed.

boats like the hydroptere make efficient use of their balast. in a foiling mono this is even more critical. the boat you are talking about is unlike any other boat we've seen, precedents like the the above about can only be relevent up to a point.

 

Ballast

You're basically right-the design has to be as free of excess weight as is possible within the
confines of a self-righting monohull foiler. Look under the"Stability" thread for my post on a 90-110° canting keel which the 60 footer would probably use.
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Heres a pix of Bethwaite/Billoch's Pterodactyl which was conceived of to use on-deck movable ballast sliding in the forward cross arm. These guys are the first modern designers to propose a combination of on-deck movable ballast and a fixed keel. The 60 footer I've proposed combines their concept with Langmans canting keel on similar type of boat(pix of Langmans boat p2,post29). Bethwaites concept also suffers from the use of "mini ama's" as buoyancy pods which would certainly run afoul of racing rules.

 

my apologies doug i didnt have the background. the keel design i agree would probably work, with a few million dollars. the first image is what i think you mean and the second one is of my immediate thoughts.

 

Wow!

Wow, nfluter ,you nailed it-looks like a page out of my notebook! The only difference is that the whole hull does not need to be round on top; it can be designed to add more longitudinal strength. My congrats on the sketch-you hit the nail on the head-way to go....
I haven't had a chance to look for it yet but someone -fairly recently- posted a design for a rig that does exactly what you've drawn. It is probably on page three or four by now. Canting rigs have been used very effectively on ORMA Tris
and a few Open 60's. This boat would do better upwind with the whole boat heeled-I think...
I don't like the surface piercing foils-would be very, very difficult to sail on just one angled SP foil and the rudder foil. I'm convinced the fully submerged bi-foil is the way to go-with an electronic wand(or "normal" wand to start).
I'm very impressed by how you think, nflutter..
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PS- the pods probably have to be more rectangular so as to disuade any over-reaching authority from trying to claim they are "hulls".

 

lateral rig movement

nflutter-here is the thread I mentioned; the first post has the url of the boat being discussed.
Don't think its too applicable to the 60' monofoiler though.

 

60' Moth,I mean monofoiler.

From the latest issue(July/August 2007) of Sailing World magazine.
Question to Juan Kouyoumdjian designer of some very innovative and fast monohulls:
SW: "In the next 5 or 10 years, what about the sport will change? Where's the next big technological jump in speed?"
Juan K answers: "I think the answer to your question is to be divided in two. One side is what engineering is allowing you to do today.And from that perspective I can see boats just taking off the water. And when you start getting to the 40-plus knots of boatspeed through hydrofoils and so forth you hit the wall of cavitation, and therefore the morphing foils. I think sooner or later some people will feel the need to go that way. But the other side of the equation is what sailors want to do. There are still a lot of sailors that enjoy sailing on very big,heavy slow boats. I don't think in the general world of sailing there is an interest there to go at more than 40 knots over the water."
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Pretty interesting commentary from a leading designer of very fast monohulls....(predicting full flying monohull keelboats)

 

I think Juan Kouyoumdjian is absolutely right:

“But the other side of the equation is what sailors want to do. There are still a lot of sailors that enjoy sailing on very big, heavy slow boats”.

Sailors are by tradition a very conservative kind of people.

Wee have seen on this forum, on threads about cruising boats, seaworthiness and even racing boats (class America) that many members still prefer boats that could be designed 30 years ago (or built, in what concerns cruising sailboats).

There are others that want fast modern boats , boats that can take advantage of contemporary engineering skills, computer assisted Design and modern materials, but I suspect that they are a minority.

I agree also when he says:

...." I can see boats just taking off the water. .... I think sooner or later some people will feel the need to go that way".

But it will be a minority, at least for many years, a minority that will be scorned by the vast majority that would rely on tradition, sailing at hull speeds.

At a different level, you can see about cruising boats a similar trend (between contemporary Design and old traditional one), between boats that are designed for planing and boats that are heavy hullspeed boats.

On the side of contemporary Design, you can notice that almost all-important designers are proposing those boats. On the side of tradition, you can notice that on numerous threads on these forum there are people saying that those boats are unbearable uncomfortable and unsafe at planing speeds.

But I agree.....”Sooner or later”....

 

Nice drawing... and I have tried to describe something similar before, but a drawing is worth a thousand words.

I would only retain from the first image those lateral (big) flotation devices, that in my mind would be water ballasted. The water ballast would be subject to continuos adjustments (computer assisted and very fast) to provide the right balance to keep the boat flying. A little bit the way water ballast tanks provide stability on the big cruising ships.

 

60' Moth

Vega,nflutters sketch is good and very close to what I had in mind but if you read the original description of the idea(post#1) you'll see that the on-deck movable ballast is water(3000lb.'s max) in a tank and the tank would slide side to side perhaps inside the forward cross beam. Don't think it would have to be computer controlled,though.
Did you know that L'Hydroptere uses a PUMPED water ballast system from an intake on the rudder
all the way out to each ama? The amas are 40' from the CL! And can carry up to approximately 1760(800kg) pounds in each ama in addition to some water ballast in the main hull for pitch trim.
On the 60' monofoiler the idea of the sliding tank is to make weight transfer faster . The "buoyancy pods" on nflutters sketch are still probably shaped too much like hullls but they definitely would not hold water(intentionally).
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As to Juan K: I think its fantastic that a designer of his credibility publically predicted full flying hydrofoil keelboats -something many people still believe is impossible! I also agree with what he said about most sailors but have you noticed the kind of boat he designs: definitely not for that group for the most part-at least not slow and heavy!
I think as time goes on there will be a lot of people sailing monohull hydrofoils from dinghy's up to maxi's with foils. But it will probably never be a majority of sailors and thats fine- each to his(her) own.

 

I have understood your idea, but I prefer the water moving from one pod to another, not the tank. It would have to be a huge tank and It woul be not an elegant solution. Easy to do on a small boat, not very practical and probably dangerous on a big boat.

 

60' Moth

You may be right though I think a tank moving within a crossarm could be a good solution and certainly able to move 3000lb. of water much faster than pumping it. But the tradeoffs would have to be looked at closely. L'hydropteres's system works on a boat that is a candidate for the world speed record and that's impressive. Whether or not my system is an improvement remains to be seen.

 

Does this guy ever do a REAL calculation?

Within the beam? So maybe a 2 foot diameter tank? Hmmm, that means a 15 FOOT LONG tank!

Where's the CG of this tank then? How much is that CG going to move tack-to-tack?