Sailrocket 2 set to launch

Doug you seem to be really up on this project, is there any practical application of this design? I have an outrigger canoe, theoretically could I adopt the canted sail and foil to my boat (in proa arrangement) and achieve a similar balancing effect, reducing drag? How similar is this to the "lifting" pacific lateen sail concept?

If the sail force is headed "up", and the main foil force is pulling "down", how deep does that foil have to be to actually provide "down" force? I mean, if it was only a few feet down wouldn't the weight of the water above it not be enough to stop it from rising? Am I understanding this concept well enough?

Sorry for all the questions this is just so interesting to me...

Dam, another question, would this concept work on a run? or are you just always going so fast that the apparent wind is forward? (I'm thinking from a practical standpoint, say in my outrigger canoe on a run)

 

Sail Rocket

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I haven't spent enough time trying to understand this concept though I've been wanting to. I'll look into it more when I can. There are several "flying" speed sailing concepts out and about now like the V-44, Wot Rocket and one or two others. The Sailrocket site has a large amount of detailed information.

PS- While I admire Paul Larsen and this team a lot and wish them the best the fact that this boat only goes one direction is a mark against it as a "sailboat" in my opinion. Both Hydroptere and the V-44 can sail on either tack and Hydroptere is hands down the winner with her rough water capability.
These guys will prove something if they break the record but I'm not sure what-except that on one tack this is a very fast sail powered device. If you watch the last video you can't help but pull for Paul Larsen who effervesces with enthusiasm and dedication-the guy is giving it everything!

 

I just wonder whether the concept of a lifting sail and canted foil could be (or has ever been) utilized on a less radical proa, for daysailing not outright speed sailing...

 

Sailrocket 2

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I don't know about on a proa but the Moth uses lift from the rig and foils to go faster than any other small sailboat under 20' or so. The rig lifts vertically as do the foils. The angled lift from the hydrofoils unloads the vertical fin(daggerboard) so it is less likely to ventilate while most of the lateral resistance is generated by the same foils. It is a rather neat combination of forces and moments not seen on any other kind of sailboat*. It would be hard to visualize a better system on any type of boat-but the "flying" boats, that eliminate the requirement for extra RM altogether, will be extraordinary if they can be made to work and sail on both tacks. I think a lifting sail and a lifting canted or curved hydrofoil could work on a proa but I'm not sure how it would compare to a "flying"(Sailrocket/ V-39) system or the Moth type system-but it would surely be fun!

*one of the Moth contributions to the physics of sailing has been "Veal Heel" where the CG of the hull(and everything else) moves to windward. The movement of the hull CG to weather is not seen on any other type of sailboat.
Veal Heel is a technique where the crew can be hiked as far as possible with the boat level and then "feather" the boat into windward heel without physically moving and just the act of heeling to weather allows the boat to have 20-40% more RM then it had with the boat level and the crew hiked max out-pretty amazing. It is essentially "free" extra RM...and only possible on a bi-foiler. And it can be duplicated on full size boats as well-including,I believe, on a self-righting keelboat. We'll see....

 

40 knots today!!!

Way to go Team Sailrocket:

Today VESTAS Sailrocket 2 strolled over 40 knots to become the second '40-knot sailboat' based on the concepts of Bernard Smith.

It really was effortless.

We made some changes to the pitch of the main foil in order to help lift the rear float clear of the water and it all worked a treat. The steering was great and it all just felt smooth. To be honest I was surprised that we hit 40 knots. It turns out the average was 37 knots over 500 meters. The wind wasn't that strong. Maybe 20 knots.

SWEEEEEEEEEEEEEEEEEEEEEEEEEEEEET!!!!

We still aren't hitting the numbers of the first boat but then these are still early days. Malcolm thought that we would have ventilation problems around the high 30's and he may be right. Whilst fences would help sort that problem out, I decided to peel straight to the cavitating/ventilated section. Jeffro and Jonny were dispatched back to the container to pick up the other foil... and a bottle of Champagne. We plugged the new foil on and headed back up the course. The wind had died enough to deny us another good run with the new foil so we happily called it a day.



ANOTHER BOTTLE BITES THE DUST.

This is all in stark contrast to the effort we put in to getting the first boat over 40 knots. That took three years and quite a bit of trauma.

So now we need to see the new foil work. If it does then it will be an all out speed grab. The trouble is that tomorrow may well be our last day with any decent wind. Well, we will see. One things for sure though... this new boat is 'gagging' for it.

Nice one 'Barney'. This bottles for you.

Cheers, Paul.

-picture on right shows wing extension(5-25-11)---click on image:

 

Unlike Doug and some others, I can equally admire both those that go for the ultimate in sail powered water craft (one tack if needed), while at the same time cheer on those that do the best while retaining the ability to tack, navigate, deal with open water. etc.

Now, speaking of Sail Rocket 2, the progress has been amazing. The test runs are showing off huge gains in handling and stability.

The layout changes of the platform seem to have fixed what needed to be fixed and now the next steps are mostly just smoothing out details and then trying to finally slay the cavitation monster that has never yet been truly beaten in high speed sailing.

Here is to the Sailrocket Team. All of the team. Those that did the layout changes and design work, those that did the building and all those on location now.

Their effort just makes this engineer proud. They are truly showing off the Bernard Smith approach of making physics work for you (balanced primary forces, inherent stability, etc). When it come to exploring how fast a sailboat can truly go, I see this as just so much better than the more brute force approaches like incremental improvements to a traditional platform (foils on a large multi-hull).

May the gremlins stay silent and the weather co-operate so that this team can show the world what can be achieved by a dedicate team with a do it smart and do it right attitude.

I really really hope that they make good with a huge leap in performance that I feel is theirs for the taking. Knowing that cavitation can really be handled, breaks down a big mental barrier and opens the door for other to try new ideas in high speed sailing.

Go SR2 Go!

 

Sailrocket 2

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I may not admire the design of a one way speed sailer as much as I do a speed machine like Hydroptere-but I equally admire the people behind both projects. I've proved my admiration for the Sailrocket team by updating this thread as often as possible. I wish them great success!

 

40 knot video!

Check this out and note how the rear planing surface is flying when the foil kicks in: http://www.youtube.com/watch?v=PKkj2vwmQko

http://www.sailrocket.com/

 

.

Their main foil does go down more than a little. However, it is not the weight of the column of water above the foil that is used to generate the down force component. When the foil moves through the water it accelerates water in a direction opposite to the force generated. The mass of the water moved multiplied by the acceleration is where the force comes from. A subcavitating foil operates pretty much on Airfoil theory. Airfoil theory is actually complicated when you try to figure out how the flow around the foil cause the fluid to move like it does. Supercavitating foil theory is probably an order of magnitude less well know than regular airfoil theory (SR2 has both available and is trying out the supercavitating one now). However, for this discussion, the details of how a foil causes the fluid movement is less important than the simple fact that fluid is moved and the acceleration and mass of this movement produces the result.

 

Well said. Point noted. My bad on on they way I put it.

 

That boat looks exhilerating i want one. When r they going into production?

 

Sailrocket 2-the end until September

from Paul Larsen:

Tue, 31 May 11 16:57
Well, I'm standing here in a half peeled Musto drysuit. Unfortunately it is coming off rather than going on. We have been on full 'booted and suited' standby with Jeff over on speed-spot giving wind reports via the VHF. The whole base camp has been pulled apart and only VESTAS Sailrocket 2 sits out there intact... but not for long. We are about to descend on her like a bunch of insects and dismember her for storage.

We did all we could to have one more shot but the wind didn't play ball and the 50 knot bottle remains corked. There's nothing we can do about the weather other than be here fully prepared for when the good stuff comes.

On the up side... we have survived the first full testing session fully intact. We have made nothing but solid progress and have introduced the second true '40-knot sailboat' into the world.

This isn't the windy part of the year so these 'soft' days are pretty much the norm. For the same cost we can come back when the wind is pumping and get more full-on days for our dollar.

So that's it for now folks. The next sailing day will be in September. The team will have changed. There will be some old and new faces joining us although I have no idea who it will be right now. It depends who is available. This team has been great and we have had a lot of fun. It really doesn't feel like work despite the silly amount of hours we spend around the boat.

Thanks for all your comments and e-mails of support. They are all read and all appreciated.

Ok, we have a lot to do so I will leave it short.

I'm happy.

 

Well, a record chasing sailboat finally seems to be making progress at beating the foil cavitation monster. Sailrocket is back in action and doing well with the supercavitating foils as can be seen from Paul's words:

"The steering was responsive, the sheeting was very responsive. It was obvious we were over 40 knots. I was happy with the fact that we were now at a stage where the boat was just simply working. We haven't seen the outright performance but it will come. It appears that we have no mid range bogey man with this new foil... unless they are waiting further down the path. We all figured that this new foil should start to work properly at around 40-45 knots. We are there now. This foil has no top speed limits other than it's own structural limits. All the issues that limited the outright speed potential of boats like VESTAS Sailrocket 1, Hydroptere and Maquarie Innovations do not apply to this foil. "

Read more at http://sailrocket.com/node/398

 

Sailrocket

Thanks for the update, Mr. Flados-slipped my mind.... I wish them well!

click on image:

 

Speedrocket

Looked like a bad day(too little wind) so Paul called it off. Then the wind came up but too late----missed oportunity.
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UPDATE: 10/5/11- light air on standby..