Sailrocket 2 set to launch

SailRocket

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I'd say there are few limitations to speed increases-100+ knots may be possible with a different boat depending probably on the foil and engineering limitations.
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Does anyone know what Bernard Smith called this type of boat?

PS- just added "The 40 knot Sailboat" and "Sailloons and Fliptackers" to my library.

 

The concept needs a new name unless "Sailrocket" is adopted as a generic name.

I don't see it as a foiler. The foil holds the boat down more than it supports it, and its prime mission is to control the course together with the rudder. It's more of an aircraft with a foil-shaped sea-anchor, and is not far from a kiteboard in principle.

 

I have seen a couple of posts (various locations) discussing size.

Larger size can improve the basic physics and enable higher speeds.

Larger size means the need for a longer course.

Much larger and you probably lose the ability to manually position it at the start of the course and to manually launch and retrieve it.

Get much bigger than SR2, and you probably need to design full any direction sailing capacity and you end up operating more like Hydroptere.

Got a six digit sponsor handy?

 

Like Foiling Moths it will have to be possible to sail on either tack and once that is achieved it may prove feasible to sustain highspeed in any - or at least most - directions by tacking downwind.

There is a concept called the FlipTacker that solves the problem of sailing on either tack. I came up with a similar concept independently at http://www.boatdesign.net/forums/sailboats/highly-assymetrical-wing-sail-25362.html but did not complete the build, although the deck, turntable, micro-amas and foils were built before health issues got in the way.

 

Digits

Seven !

 

Sail Rocket

The record run:
http://www.youtube.com/watch?v=wnjyusAgk8I&feature=youtu.be

 

This argument is starting to resemble the "Definition of Planing" thread. Except here there is also aerodynamic lift, which is rather unambiguous.

I would characterize SR as more of a WIG (wing in ground-effect) vehicle rather than a foiler. The foil is the minimal "toe in the water" that's needed to extract power from the air/water interface, and its tilt and resulting downforce are only a matter of geometric necessity to align the foil and sail forces.

Imagine an SR which is 500 feet wide, still using the directly-opposed foil and sail forces. But now the foil and sail would be nearly vertical, so the vertical forces would be negligible. By the "significant vertical foil force" criterion this wide SR would not be a foiler, even though it's basically the same concept.

 

Sail Rocket-new record today!

From Paul: http://sailrocket.com/node/640

Sun, 18 Nov 12 20:28

Just in after the most incredible run. A whole nautical mile dipping well into the 60's on each gust. We peaked near or over 64 knots and beat our previous 500 meter average. I don't think we cracked 60 knots as a 500 meter average though. But anyway... we smashed the nautical mile record. The TRIMBLE file is big but on the small GT31 we averaged over 55.5 knots

(Hang on STOP PRESS: Trimble data in now... 55.32 knots for the mile subject to wssrc ratification. That's it).

63.98 knots 1 second peak... so definitely over 64 for a spike in there.

... and just marginally quicker than our previous best 500 meters at 59.38 knots... subject to wssrc stuff!

 

Doug: great news, who had the nm record before was it l'Hydroptere?

Mark: what argument? Did I missed it?

However if the concept gets scaled up enough then sufficient speed may come from length & maybe wave-piercing hulls, and foils won't be needed. They would be at risk on trans-oceanic voyages with all the lost containers floating around in the ocean. A big vessel would need power-assisted controls and automation but with size that's no problemo . . .

 

Sail Rocket

Terry, a windsurfer in 2006-after that it was all Hydroptere up thru today! http://www.sailspeedrecords.com/nautical-mile-records.html

 

SailRocket

"Hybrid planing foiler" ?

From "Facts" :
• The curve of the main foil determines how high the boat rides.

• The back of the boat will lift* onto the curve of the foil at around 25 knots. The leeward float will begin to fly clear of the water over 50 knots. Only the main foil, the rudder and the 'step' of the forward float will be in the water at high speed.

* my emphasis: aero "lift" or does the top of the foil initially "lift"?

http://www.sailrocket.com/node/292

 

it met the letter of the rules, so it gets the record. It would be interesting to see a new class that requires back to back runs in both directions, highest average wins.

with a sailboat that can run in both directions, you might actually approach a practical sailboat and develop designs that would have application in conventional racing sailboats.

 

Even if a new class was set up, I would expect little competition.

The one mile record does not get much focus as it is.

Those going for the "fastest boat" want the outright record, not "something else".

Those going for the "fastest real boat", are those chasing the transatlantic, the round the world and similar big accomplishments (e.g. Banque Populaire V).

Those wanting to go as fast as possible based on skill & physical ability chase fastest windsurfer and/or kiteboarder records even if these are not the outright record.

For the rest of the sailing world, there are some opportunities to chase records for specific races and or the record for point A to point B.

Given the above, I do see a big push for a new class.

 

Sail Rocket

For all interested in the burning question: "Is SailRocket a foiler?" , please read the description of equipment below:


For The Record


The WSSR Council announces the the establishment of a new World Record.

Record: World "B" Division Speed Record
Venue: Walvis Bay. Namibia.
Name: Paul Larsen. AUS.
Equipment: Vestas SailRocket 2. Inclined rig Hydrofoil Proa.
Date: 12th November 2012. 18.30 hrs
Course length: 500 metres
Current: Nil
Elapsed time: 17.97 secs
Speed: 54.08 kts

Comments: Current record: Vestas SailRocket 2. Paul Larsen AUS. Walvis Bay NAM. 2011. 49.19 kts

A further claim for a speed in excess of the above is currently being assessed

John Reed
Secretary to the WSSR Council

 

"But SR is as dependent(or more dependent) on the lift from the hydrofoil as it is on the lift from the wing or planing float.
It's tough for me to shake this analysis of the boat based on the action of and importance of the foil. This boat is as dependent on lift from the foil as is any other hydrofoil, right?"
Doug, I think you're dead wrong here.
I think SR2 is actually more of a 30ft carbon-copy of a kitesurfer (pun intended).. Look at the forces in play, the wingsail is trying to pull the boat out of the water, the foil is holding the boat DOWN, not lifting it up. Yes, the long part of the foil lifts the rear up while accelerating but then it is out of the water and the short part of the foil is holding the boat down. The force in the wing is enough to carry the entire weight of the boat at over 50knots, so the foil is only there to keep the aircraft attached to the water (at this point aircraft is a more suitable term than boat).
I know you will cling to the idea that it can't possibly be fast if it isn't relying solely on hydrofoil technology to make it work, and the WSSRC's definition of an inclined rig hydrofoil proa supports your theories, so keep the faith, but don't be surprised if some of us see it otherwise.