SpeedDream: World's fastest sailboat?

i disagree doug about making a mono faster than a multi. the reason i say this is i believe that once the boat is running on the foils it should not be considered a mono hull, the hull is not in contact with the water so how can it be compared with a normal design. these foil boats are impressive but they should not be classed as anything but a foil boat. thats my 2 cents anyway.

 

=================
I see a lot of this. In order to let people know what he is trying to do and raise the money for sponsors a designer has to project the performance that he is shooting for. Then he is accused of "hype" and making "PR claims" in an effort to denigrate the concept when neither he nor anyone else knows
for sure whether it is possible or not. It is a damned if you do, damned if you don't situation for any new project that is intended to push the boundaries of design.

 

When it comes to absolute speed records it's about the speed. It's not about foils or the number of hulls or the size of the boat and it's certainly not about classification.

 

-------------------------
Whitepointer, thats a tricky assessment. The hull(or hulls) on either a monohull foiler or multihull foiler is supporting the structure that is in the water I'd say they are one and the same, pretty much. Also, any ocean going foiler has to be able to sail on or off foils. Then there is "foil assist" that Vlad is talking about where the foil reduces the displacement(and therefore the wetted surface) of the boat without flying the whole boat(intentionally). Same concept as Banque Populaire which uses a single foil in each ama to lift a large proportion of the boats weight. On the Orma boats and the new Mod 70's the proportion is up to 70%.
And then there is clearly a difference between a Moth(monohull) foiler and, say, an Osprey(multihull) foiler:

 

I'll take that bet. Let's say the amount of money you just received from your brother's estate. The bet is the SpeedDream will not surpass the round the world record of multis in the next 5 years. I would give you 10, but I don't think you will be around by then.

 

I guess thats where we part direction in thinking then. The small speeddream concept should give a guide as to the performance potential of the larger boat and sorting out systems, announcing the large boat in advance is a counterproductive action and yes it is "hype" whether the term is palatable or not. All we have to discuss is the original press release as no substantive information or results are available for scrutiny as yet.

I'm excited by new development too and think that Vlad is very wise to hitch his wagon to a monohull speed design as there appears to be no shortage of investors for large monohulls so it's a good area to exploit with a new design.

If you look over the history of multi development of recent years there have been record breaking boats built but few claims made the boats have proved themselves with results rather than words. Early claims made by multihull designers like Piver with his 1000 mile days and riding round the world on one wave did more harm than good.

 

On a smaller scale, I must admit I have a tendency to pre-announce my intentions in the boat designing or building sphere. For me, it then obligates me to make the effort to follow through,whichis a plus as I can be a bit lazy. Maybe I'm not alone . . .

 

-------
In that case, perhaps the "discussion" should be limited until the results are in and the attempt accepted on good-faith face value.

 

It could well blow up in Vlad's face. What if his Speeddream maxi is "only" capable of 800nm days the boat will still be viewed as a failure even though it's significantly faster than any other ocean going monohull.

I also have some concerns with the design in a broach scenario where if the DSS foil stalled when the boat was powered up it would not be a pretty sight. In that situation I can imagine the boat presenting side on to the wind the hull becoming a fulcrum with that long telescopic keel bulb coming over the top with its mass accelerating the boat into a violent capsize. Now it may be that the keel can be release quickly enough to prevent such a scenario but it's just one of many "what ifs" that could and should be asked.

A monohull travelling at multihull speed has to start considering the same speed related issues that effect a multihull pitchpoling and other rapid capsize scenarios become more probable and even likely.

 

==================
With this you take "negative imagination" to a new level! And you fault Vlad for his "positive" imagination! Such a thing has never happened with DSS and, if you understood how it works you'd realize why-the foil is set at a low angle of incidence and when moving fast it is virtually always in the water. I remember comments made in the old days about curved lifting foils never working because if the curved lifting foil stalled when the boat was powered up it would not be a pretty sight. Curved lifting foils would ,a very few times before their design was understood, lift the whole boat and ventilate-not stall. Almost every modern racing multihull from beach cats to AC boats now uses those foils.
If a DSS foil was to ventilate that would occur at a time the foil is very close to the surface and already not contributing max lift-otherwise it simply would not happen. You presented an imaginary scenario , not based on how the foil actually works, in an effort to denigrate Vlads approach. Thats the kind of thing that doesn't help the discussion because it is not based on how DSS actually works in the real world.
You and some others feel free to criticize Murnikov's concept with imaginary information that bears no resemblance to the actual way the thing works. Thats unfortunate and maybe the criticism ought to wait a bit untill there is a prototype sailing. He may not even use DSS......


Picture from Ocean Navigator:

 

I agree that scenario is not worded well stalling is not the appropriate terminology. What I'm envisioning is a sudden loss of lift from the foil as the boat comes into a broach with wind and keel on the windward side of the boat. If you have experienced a broach you will realise how quick and violent they can be and they happen on modern monohull designs as well. Normal canting keels dont fly high out of the water so remain below the boat in this scenario the relative angle of the keel would appear to be much greater relative to the rotational axis of the boat. The DSS foil would be almost irrelevant at this point as it would not be generating lift with the boat almost stopped. The argument could be made that the same could happen to a multihull but they have much less tendency to broach in the first place. Maybe I am possessed with negative imagination and there could be some perfectly logical counters to this scenario as well maybe the lift from the DSS foil helps with preventing broaching?

 

=================
Well, I wouldn't go that far... Lets try this: how many monohull round the world record attempts, or round the world races with Open 60's or VOR 70's can you think of that have ended because of a broach? You said a "broach scenario where if the DSS foil stalled when the boat was powered up". I suppose you meant "what would happen if the boat that had a DSS foil broached"? Any boat can broach but the DSS foil doesn't stop working during a broach and, according to the designer, simply helps the boat recover more quickly than it would otherwise.
Speed can screw up the best laid plans-stuff happens whether you have DSS or curved lifting foils or whatever. I just don't think focusing on invented scenarios with a technology that may not even be used is beneficial.
I think the guy should be given the benefit of the doubt and not be subjected to unfair, uninformed or speculative criticism. Why not discuss how it could be done?
Here is an idea of mine from a few years ago-still think it could be done and that it would beat any multi the same length.(Is that "hype" or is that a genuine reflection of the designers belief in the concept based on facts and extensive study,huh?)
http://www.boatdesign.net/forums/sa...acing-monofoiler-design-discussion-15143.html

 

I have big doubts about a monohull beating the multis in OCEAN racing.

1- The comparison the 14 feet foiler against 20 feet cats is inexact with ocean going sail boats. I would like to see a 14 feet in strong breeze, condition manageable with a 20 feet cat. And the big multihulls have already (small) foils.
2- The actual big multis like BP 5 are just a transition between displacement multis and foilers. The experimentation has been successful and I have pretty good info that new multis with more foil sustentation capability will be built into the 2 next years, and thus probably faster. The 1000 miles day will be largely broken into the 2 next years, well before the mono is built. One French NA is talking privately that 1200 miles day is possible withing 5 years.
3- The actual goal is to get a multi able to fly in good conditions but keeping a good speed when the conditions are adverse. So the foils are removable and adjustable.
4- The monohull is not the best platform to solve the equation power/stability as it lacks cruelly width. Without foils a monohull has no chance to beat a multi of similar size.
5- In ocean racing you have all kind of sea states, from flat calm to tempest with any direction of wind. A big multi is able to manage all these conditions, and are pretty fast upwind. A monohull made for reaching is zero upwind if the conditions are unsuitable for the foils.
So the multi has a better mean speed, and a probably a better final speed as it's able to carry more sail and has more stability.
6- Last but the more important, multis have already a long time of trials, have a lot of data, the system is mature and do have a steady financial system with the French Flying Circus (the other countries have renounced to follow the froggies: no engineering data and no experimented NA and NE, no shipyards, no skippers, no crew, no sailmakers and riggers, no specialists, no press so no advertisement results, no organization and no races so no money...The Frenchies have all that).
It will be very hard to find the money for a totally "unknown" system using a mono.

 

Any skipper who allows an experimental high-speed boat to experience a broach is likely to be judged rather harshly IMHO. Similarly any boat can get its come-uppance in sufficiently severe conditions.

Little is gained by batting what-ifs and absolute statements back and forth. It's a promising concept that needs its chance on the big stage. Time to agree to disagree and move on . . .

 

Okay, now where's the research that leads to people making these claims about this boat?

There has to be research behind this boat....so where is it?