Quant 28-foil assist keelboat / DSS

Quant 28-

Sound bites from Mr. Welbourn-(from SA)- addresses question I and others have had:

#1

Draaaag....and no, none us do drag without a good reason)

Look at it this way - every item in the water causes drag, so to be there it has to have a good reason to be doing something important...so keel holds a lump of lead on the end and also provides sideforce which you need. Rudder produces sideforce. Both have viscous and induced drag but you need them.
Hull supports the thing in the water thanks to Archimedes, and has viscous, induced ( from leeway ) and wave drag.

So the DSS foil adds viscous and induced drag, but also can operate in various modes depending on immersion depth - so close to the surface it can be a nice effective planing surface, partially ventilated then likewise but a lot of the viscous drag has gone and if its got there then you aren't using all the RM/lift that it might be producing so it doesn't need to be working hard as a fully immersed foil.

Lift and RM....both are significant, and each design has its own requirement in how to best approach the foil and overall balance.

If you look at the video then you can visibly see how little the hull is contributing to wavemaking, wetted surface is low and also well aerated, and so we're bimbling along steady 15-16 knots and maxed 17 in about 10 TWS and only three up - me driving, German Journalist along for the ride and Kos up front.
Boat is in perfect balance, wouldn't be doing those numbers without the foil.
Bit later on the breeze came up from a thunderstorm and we were doing the same numbers and a bit more just on the working jib.

Lots more video from that day, and the weather side views make it look as if nothing is happening - practically no spray, stuff all hull in the water. But note, I'm not trying to fully fly the boat as then you get into all the trim problem - so its designed to have natural dynamic stability.

And btw - we've done extensive testing on the 27 in big waves and seas down off Sotogrande and never had any issues from launching off waves or burying or any signs of tripping.

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#2

Upwind - well the thing here is to match the wing parameters to the boat so that the net result - in steady state - is just slightly in your favour. So RM gain outweighs the drag cost.
However, what we then find is that as soon as there's any chop or seaway to move the boat around, then the damped motion in all axes makes a significant improvement that is seen on the VMG - even when you only seem to be sailing maybe a tenth quicker than you might. Now that comes from logged data and was a bit of ( pleasant! ) surprise to me until I figured out the dynamics of what was going on.

And don't forget, you don't need to use the wing at all until you are running out of natural RM, so no draaaag....until its starts to work and then the balance is in the your favour.

Its all a pretty finely balanced configuration but we've got a good handle on thing now from all the r&d and sailing and how to configure the different types of boat to work.

Downhill vmg - then same again - if you don't need the wing trickling along then its out of the water, but as soon as you can get into the situation where you can AWA sail then the more power you have to use the better. Bit like cats or skiffs, but cats can't get the spare hull out of the water until theres enough breeze, and skiffs or canters all have a fixed max RM.

So the AWA you sail on the 28 downhill is always well forward, but the angles you actually gybe through can be less than more conventional boats.

Thing is, got two boats in one here - the light wind one is skinnyish with very low drag, but you can add in the grunt when you need it....

Start of the Bol d'Or - dead downhill, bit of breeze - ourselves and the 36' trapeze/canter Full pelt bolted off the line at 15+ and were a mile clear of the fleet in 10 minutes - and crossing gybes with some of the cats that started 300m in front of the mono fleet....they were a bit confused to see us in 'their' water

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#3

Bit epic! Start was great - legged it off into the distance and then the wind did its usual crap out for the leg from Petit Lac and up past Evian. Didn't seem to be going that well along there but figured maybe just rig height v the bigger boats like the Psaros 40's and Libera that crawled up and past.
By the time we got up to beating up the cliffs on the French side though we started really feeling something wrong - opened up the wetbox ( has the roller drive in it ) and then found that one of the access covers forward wasn't on properly....so the front of the bus had been filling steadily up with the water. Bollocks. Managed to get some of it out but by the time we got to baling it out properly next day we reckoned had about 350 kgs of the lake along for the ride.....and thats not quick! Add in some monster clumps of week we must have picked up in the last few miles and we had a lot of hard work for no result. Reckon that 20 boats passed us in the last 10 miles which was painful but nothing we could do about it.

Still - good news was that the rig stood up to it all OK, broke nothing, we know we've got great all-round pace, but must add some draining facilities!! And better hatch covers too....have to come back next year and have another crack at it.

>>>>>>>>-Wow! did you see this: "opened up the wetbox ( has the roller drive in it ) and then found that one of the access covers forward wasn't on properly....
So thats how it works: roller in a sealed compartment impinges on surface of foil-crank the roller and the foil slides! Brilliant!

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#4

...well you'd better remind him that we are happy to license the patented system, and that one of our investors is a major international lawyers company.....and if by some chance a boat gets built outside of our 28 and counting patent covered countries then the moment it arrives somewhere else that is covered it will be liable for a licence fee. Its only about the cost of a mainsail for a typical boat btw.

 

Quant 28

from the owner on sa:

Posted Today, 04:11 AM

Hi guys

I own the Q28 and maybe i can end some parts of the discussion with my thread.

Listen it is a lakeracer. We (Hugh, Kos, me) designed it like this and for this purpose. A light boat for flat water to sail in light conditions from 2 to 15kts of wind. Sure you can do sail in more (Bol d'or was up to 27kts some of the time) - but as we have the named wind conditions in about 85% of all races it makes sense to do so. ok?

Now with this boat, which is different from the 25' of Murphy (much skinnier to sail upwind also very well) we got 2 boats in one: 1 light boat with lots of sail and foil in for light - and second: light boat with foil out and lots of sail for more wind to produce stability. So forget about drag, you just leave the foil in center position or put it to weather side, as you sail along in low windspeeds means no drag but still light boat and looooots of sails.

If wind picks up you go fast then you put out the foil and by going fast the foil produces lift to right up the boat and lift to reduce drag of the whole boat (the whole boat is lifted means less drag in the whole system) and also to stabilise the whole system in any axle (you actually can walk around in the boat while going fast, it just doesn't move) this helps aerodynamics and hydrodynamics. if there is some chop, the boat is just hammering over it, like a surfboard.

Look at the clips on youtube. The boat accelerates like a some cat and there is now wave at all just look at it and stop silly discussions. no waves means less drag. Ok? Even people on our lake - not the most skillfulls sailors under the sun got it and also people in Geneva got it - although not invented there - they liked the Q28 and the idea from the first moment. Also the Journalist from "Die Yacht" (biggest magazine in Europe) got it quickly. He changed from sceptic to enthusiasm in 2 hours. It is that simple. You do not have to have a DSS boat but it is more interesting, more fun and it is going in the right direction with a amazing simple system that even amateur-sailors just learn to handle in one season. If it is very windy of course it helps if your are a Skiff sailor or Cat sailor because then the boat is a monster, even if it is only 28'. So please no more crusades it is just not worth it - if somebody doesn't like it - ok. no problem.

Have a nice day and cheers from Zurich (Switzerland9

 

DSS Patent

For those interested in learning more about DSS here is the patent number and abstract:

Patent Number: EP 2004479

Pub. No.: WO/2007/116318 International Application No.: PCT/IB2007/001455
Publication Date: 18.10.2007 International Filing Date: 05.04.2007

IPC: B63B 1/30 (2006.01)
Applicants: DYNAMIC STABILITY SYSTEMS LIMITED [CN/CN]; Suites 1601-1603, Kinwick Centre, 32 Hollywood Road, Central, Hong Kong (CN) (For All Designated States Except US).
WELBOURN, Hugh Burkewood [GB/GB]; (GB) (For US Only)
Inventors: WELBOURN, Hugh Burkewood; (GB)

Agent: JONES, Graham, Henry; Graham Jones & Company, 77 Beaconsfield Road, Blackheath, London SE3 7LG (GB)
Priority Data: 546441 07.04.2006 NZ

Title (EN) HYDROFOIL SYSTEM FOR MONO-HULL SAILBOATS
(FR) SYSTEME D'AILE IMMERGEE POUR BATEAUX A VOILE MONOCOQUES

Abstract:
(EN) A monohull sailing vessel (102, 202, 402, and/or 502) having a lifting hydrofoil (104 and/or 204) having a stowed position and a deployed position in which the hydrofoil extends outward of a leeward side of the hull (138). The hydrofoil may have an aspect ratio greater than 2.5:1, may be oriented at an angle of attack between 2 and 6 degrees, and may be oriented at a mean angle (124) of between 5 and 20 degrees to horizontal. The hydrofoil may have a projected area adapted provide a righting moment and a lifting force for partially but not fully lifting the vessel out of the water. The hydrofoil may have an exposed span (112) that is greater than about 7% of a height of the tallest mast (134). The vessel may include an actuation assembly (128, 228, 308, and/or 316) for moving the hydrofoil between the stowed and deployed positions.

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click on image:

 

Quant 28

Quant 28 results from 6/25/11: http://www.quant-boats.com/documents/ZYC_2011_Zieleinlauf.pdf

 

DSS 27' test boat video: http://www.youtube.com/watch?v=R99LHvldlzM&feature=player_embedded

 

Quant 28-DSS working very well!

For those that may have missed this previously here is the link to the extraordinary video of the Quant 28 sailing very, very fast:

http://www.youtube.com/watch?feature=player_embedded&v=DwDGKghV8fU

 

Nice video. That foil really works well, the whole boat looks like it is just gently touching the water.

 

Quant 28 foil drive

From the Quant 28 website(see first post) here is an illustraion of the "Foil Drive":

click on image--

 

Quant 28-Seahorse

From Andrew Hurst, editor of Seahorse magazine-THE magazine of racing sailboat technology:

Following our look at the new DSS-enabled Quant 28 a number of videos of this interesting boat sailing have appeared on the i-Tube thinghy. Find a minute and take a look; what is apparent even with this early example of a new approach to righting moment generation, is that the boat displays signs of lifting as the DSS foil gets going. Numerous investigations are already underway into the balance between lift against drag whenever vertical lift is generated in a monohull sailboat, but the signs are there with the Quant 28 and using a quite different approach.

video:
1) see post 21,
2) http://www.youtube.com/watch?v=neYt-BthR4U
3) http://www.youtube.com/watch?v=A8A9GIKyqcI
4) http://www.youtube.com/watch?v=0bxQcbkarVo
5) DSS 25 "Bay to Bay" 2010: http://www.youtube.com/watch?v=D-ogozAZ24I&feature=player_embedded

 

Seahorse article about the Quant 28:

 

Quant 28/ DSS

Here is another DSS article from Seahorse 2010-rc model testing was done by
Hugh Welborn in the early development process:

 

Mystery DSS boat from SA

This will be interesting!

click on image to see the foil:

 

Mystery solved

This new DSS boat is a mini transat 650 built by Isotop. More and maybe a separate thread for this exciting development as I find it....
Probably one of the more exciting things in the offing for DSS is an Open 60 since the class approved DSS.
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facebook page for DSS-includes recent race results for the Quant 28 and "Brace,Brace,Brace" : http://www.facebook.com/pages/Dynamic-Stability-Systems/108260099200602


click on image:

 

Quant 28

The boat won this regatta: Saisonfinale, Samstag 25, September 2011 beating a Libera and ,apparently, winning overall for the year. Congratulations!
See Quant 28 "news" on their site from the link in the first post.

 

Pretty amusing.