Speed Dream 27 Prototype

Speed Dream

I like the video more as an introduction to Vlad. Seeing him in person, his genuine enthusiasm -makes the video worth watching.

 

I also like that CFD video: http://www.youtube.com/watch?feature=player_embedded&v=Me0qL6__Guk
Here's another 27 by a hot designer - to my mind one of the hottest right now: http://www.youtube.com/watch?v=VFRsWH0R7Tg
Of course this is a simple sport boat, not comparable to the SpeedDream27. Yet it's interesting to see the hull shape choices (Manuard seems to favor a fuller bow) in action.

 

Speed Dream

In the TED X video, it appears that the boat is being sailed like an Inland Lakes scow to maintain the angle of heel, keep the keel out of the water, and keep the wetted surface low.

 

Nice video. He certainly is enthusiastic! The CFD shots in the vid Stephen posted are confusing - surely the boat will still pitch in waves? It certainly seems to pitch in the sailing vids, not unexpected given the light displacement and ballast so far from the buoyancy centre. It seems to be a very physical boat - again the light displacement which will make any 27 footer fast may have other trade-offs, twitchiness being one of them. Look forwards to seeing some performance figures. Btw, think he should perhaps rein in the claims about the MX-Ray being the fastest boat of it's type - maybe reaching, but then by all accounts a Laser is faster around the track. Single condition boats always strike me as being a bit like downhill skiing with no chair-lift to get you back up again...

 

Also look forwards to seeing how it handles big breeze and a Solent chop.

 

Dont know what to make of the video, looks more like self promotion than anything else. The boat should be fast, but it also looks very specialised. As Andy implies powering through a short steep chop to windward is very different to flatwater sailing on a warm day.

Commercial success may be another thing altogether.

 

Given how often canting keel has failed on Vendee Globe boats I'm wondering how much more extreme canted SD keel will behave when boat is driven hard into the choppy seas rising over the waves and impacting hard into next wave with keel canted horizontally. There will be lots of stress on the keel strut and the hinge mechanism and canting system.

 

It is the wrong way to go; the extreme cant and depth is plainly way off course. Better the multihull configuration if you want righting moment rather than a heavy weight way out to windward. But if the intent is to make a monohull faster than a multi, (a lost cause) then DSS is a better tack to take.
Also I remember Bruce Farr saying way back in the day of the revolutionary NZ lightweight board boats that he preferred the centre of pitch to be close under the boat rather than a great distance down and to windward. I realize he was cherry picking in regards to defending the board designs against the anger arising from these lightweights cleaning up the outmoded fixed keel designs - but he was right.
Vlad can perhaps later, after pitching faults become too extreme, dump the silly, twitchy keel and go the REAL lightweight course - which is dynamic stability created by a lee horizontal foil.
It is so obvious.

 

Speed Dream

The fact is that the vast majority of canting keels have been used successfully both for racing and cruising. This last go-round of the Volvo I don't think there was a single failure. But in race or record boats designed to eck out the nth degree of performance there is always a chance of failure-so what? Chances must and will be taken to prove that new ideas can work and that's especially true in a prototype that will hopefully lead to the fastest ocean going sailboat period.

 

If he does so, he will end up with a mono that cannot self right or even self rescue (right itself with help of the crew). Then he will have a mono that is still slower than a fast multi and even more likely to end up upside down.

Safety almost always comes at the expense of speed.

What Vlad may be creating is the worlds fastest self righting sailboat.

Even there, I think he has made a few mistakes.

I would dispense with the stepped hull completely and go with flat bottom segment with a center of area a little forward of amid ship. This flat segment would curve up, rocker like, to slightly above the WL, to give upward thrust to the bow, when the boat is going fast. I would retain the wave piercing bow topsides.

Aft amid ship, this flat segment would extend, level, all the way to the stern, tapering to a point there. The surface WL , when viewed from above, would look like a elongated tear drop. The deck, from a top view, would look pretty much as it does on the present SD 27, so the crew could sit well aft and to windward.

This arrangement would be to create an aft pitching couple to counteract the forward pitching couple of the large rig.

Half the canting ballast strut pivot would actually be beneath the bottom and would have a fairing fore and aft of it. The range of the strut would consequently be reduced to about 150 to 160 deg., which at the low end of this estimate, would provide 97% of the righting moment of a perfect 180 deg. range.

 

Mono hull? Multi hull? I don' think it matters . The idea here is the same one the design every sailboat has used since the first guy attached a log to a dugout, buoyancy to leeward ballast to windward. The over square trimaran took this concept about as far as it could go. Now its about getting rid of ballast and reducing displacement with dynamic lift. I think the success or failure off the step not the movable ballast is what will make or break this project. It seems to me that abandoning the dss like foil ,or for that matter not exploring, if it has indeed not been done, the possibility of incorporating other foil variations ,Bruce to windward ,angled or curved surface piercing to leeward might be mistake. Just an opinion.

 

Speed Dream

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Mr. Murnikov has had some high power computer modeling that suggests that using the step is,ah, a step in the right direction(couldn't help myself).
This is an experimental prototype and many experiments will be tried. He certainly has not given up on foils-its a matter of one test at a time.
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New material added to website: "Design Elements"- http://www.speeddream27.com/design_elements.html

 

And I'm telling you I'm not just some blow-hard when I say it's almost surely a negative under 15 knots. I have some background, too. But yes, it's interesting that he apparently feels the positives outweigh the negatives. The probelm with simply citing Murnikov's competance is that his boat is different enough that if he's right, other competant people are wrong.

 

Sd 27

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Murnikov's performance envelope is much smaller than "normal" boats: straightline speed in wind is what the design is targeted for so light air round the buoys performance doesn't matter. If they sell some of the 27's they won't race in the "normal" way-see the latest info.

 

Speed Dream 27 was in the Lyman Morse display at the Maine Boatbuilders Show this past weekend. Anyone visiting the show could walk up and touch it. Vlad was there on Friday afternoon and we talked with him for a few minutes. Vlad mentioned that he is interested in speed in the open ocean, not in sheltered waters, which is one of the reasons he is not using foils.

The boat was heeled at approximately the angle at which the keel would be just out of the water, and at that angle the delta shape of the hull is easier to understand. It is designed to be sailed heeled on one bilge, not flat.

The canting keel mechanism is being refined based on the testing last fall. Not a major re-design but rather the sort of modifications consistent with developing an innovative, high performance piece of equipment. It sounds like they expect to be doing more testing in Rockland by the middle of the spring.