New Technology:Quant 30-Twin DSS Foil Equipped Keelboat

Quant 30

This is an excerpt from an article in The Daily Sail: ( read the whole article here: http://www.thedailysail.com/inshore/13/63696/1/dynamic-stability-systems-update )

Compared to the 28, of the 30, designer Hugh Welbourn says: “We have gone a little bit bigger and a little bit sleeker generally. It’s a production boat for people who aren’t necessarily top drawer sailors. It is fractionally detuned, just to make it easier for people to sail, but it will still be plenty quick.”

Vital statistics for the Quant 30 are impressive. Thanks to the DSS providing a substitute, areas where conventional monohulls gain their stability – the hull form and the bulb - have been much reduced. As a result the beam of her hull is just 1.95m (compared to 2.5m for a Melges 24 or 3.05m for a Mumm 30), although racks extend this to 3.6m. Meanwhile her bulb weighs just 280kg, around the same as that of the 6ft shorter Melges 24, but substantially less than a Farr 30’s 950kg. As a result the Quant 30’s all-up displacement is a feather weight 700kg (compared to the Melges 24 at 809kg or the Farr 30’s 2,000+kg).


A significant departure is that the Quant 30 has twin curved foils, rather than a single board passing laterally through the boat, as other DSS boats have. Despite being curved, the foils are deployed like a daggerboard (ie they pull out and in, rather than articulating like a centreboard) extending out laterally to around the limit of the racks.

The reason for having twin boards, says Welbourn, is so that they can be fully retracted when the boat is moored or being towed. They also eliminate some of the drag of the single board arrangement as they retract completely into the hull. Equally if you want to go out for a blast sailing two up for example, both foils can be deployed like training wheels, taking the hassle out of tacking them. Welbourn reckons that in a breeze they will also race in anger with both foils deployed all the time. “Upwind the weather one with the heel on will be out of the water and when you go downwind you’ll have a nice balancing act - you’ll be flying the boat just a little bit more than we were previously.”

The twin boards are a slight compromise for ease of use, but Welbourn says they will work fine. “It helps in some aspects - there is a weight overhead by going to two instead of one, but it’s not as bad as you’d think because they can be cantilevered rather than having to be the same strength all the way through. Also you get rid of the rollers.”

Another advantage of having twin boards is that it makes it easier for the designer to fix the orientation of the boards relative to the hull without the worry of how one single board will run through the boat. This has allowed the boards to be more immersed (Aeppli reckons the tips are about 10-12cm lower than they are on the Quant 28). In terms of their profile, the boards are symmetric so that the same mould can be used for both.

Another compromise to improve the handle-ability is that the Quant 30 features a heavier bulb, up to 280kg from the 28's 170kg, even though the all-up displacement of the 30 is still only set to be 700kg.

Performance-wise, the narrow hull shape, lightweight plus an ultra lightweight 12.15m tall rig supporting 47sqm of sail upwind and 100sqm downwind, will make the boat a weapon in light winds when the boards are stowed. The boards are expected to be deployed above around 9 knots and in 10-15 knots the Quant 28 has already demonstrated that she will readily sail at 1.5x wind speed. As the video below shows when the breeze is fully up, the 28 sails with very little of her hull remaining in the water, dramatically reducing parasitic drag.

 

Dss

This video ,in short form, is also on the Quant 28 site but is such a great illustration of DSS I thought this new , longer version would be appropo here:
For a larger picture click on the url below and then on the youtube "expand" icon:
http://www.youtube.com/watch?v=s9ilCx8B0A0&feature=player_embedded

 

Quant 30-teaser

Just got some pictures of the new foils and rack being finished:

Pictures,L to R- 1) Q30 keel fin, 2) DSS foil, 3) Rack, 4) 2-DSS foils

 

Nice work, but I am still not convinced about the stability of DSS-foilers.

First, the longitudinal stability: the foil is in the bow part of the boat, before the center of mass. The foil lift will raise the bow, that increases the angle of attack, the lift etc. until the foil loses its lifting ability due to ventilation. So, the only stable state is the partially ventilated foil, which isn't very efficient.

Next and more important, the transversal stability: DSS foil works only for small heel angles. If the boat, of any reason, heels more than some small critical angle, the foil will begin to work like a daggerbord, producing negative lift.

So, is DSS suitable for flat water only and for boats actively ballasted by the crew? I am afraid so.

But, supposing DSS really works, what do you think about a similar idea of stabilizing foil? That's no more but a pair of arch-shaped daggerboards, but they are bent outwards like mammoth teeth. They should work like DSS and a daggerboard in one.
I guess, if DSS works, this should work as well.

regards

krzys

 

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No supposing-there is ample evidence on this forum proving that beyond a shadow of a doubt.
http://www.boatdesign.net/forums/sailboats/quant-28-foil-assist-keelboat-dss-38421.html
Infinity 36 video: http://www.facebook.com/photo.php?v=10151138287219913

 

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There is a lot to read on this forum so I tried to find something that deals directly with your foil concept-take the time to read it and welcome to boatdesign.net! http://www.boatdesign.net/forums/sailboats/dinghy-design-open-60-influence-36401.html

 

Great thread! I must have missed it while lurking. I think, however, that your version of the reverse curve foil is just too short. If it stretched more outwards, it would work just like V-shaped hydrofoil. Look at the first picture, that shows the force diagram with positive vertical lift and some leeway. Such long foils can also be lifted not to stretch outboard when harbored (the second picture).

In theory, it could be possible to lift the hull entirely out of the water, using the foils together with the T-foiled rudder. However, then the stability issue becomes more important.

There is the evidence, that DSS works on flat water, with the active crew. Quant-30 is actively ballasted, too. Is there such a good evidence for heavier conditions or for singlehanded sailing? I heard about a Mini-transat DSS-foiler. Has she been built and tested? What are the results?

regards

krzys

 

Frankly, I do not understand all this criticism of the DSS concept. I do admit to have missed most of discussions about DSS so far, but when I think about it's principles, it appears to be one of logical ways of reducing total resistance and increasing the RM. Hence - speed, if that's what one is after.
Can someone please post a summary of main arguments seen so far against the DSS concept, so that we can discuss them?
Cheers

 

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You need to read a lot more of the available information: DSS has been in very rough water in the Quant 28 racing as well as the Infinity 36 racing and works very well in those conditions.
You should also read more of the thread I linked to because (approx. on page 5) Greg Ketterman shoots down my idea of the reverse curve foil due to the fact that the outboard side of the foil would have both high and low pressure present and where they meet= much drag. He actually tried his "J" foils pointed outboard on the test boat-much drag.

 

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Slavi, check this thread out: http://www.boatdesign.net/forums/sailboats/design-dss-foil-assist-keelboats-41729.html
You too, Myszek.....
Also, the new DSS website and its "Faq's" http://www.dynamicstabilitysystems.com/
Quant 28-- http://www.boatdesign.net/forums/sailboats/quant-28-foil-assist-keelboat-dss-38421.html Check out the racing record.

And Mysek: http://www.boatdesign.net/forums/sailboats/tantra-prototype-daysailer-1977-a-29954.html and this
Single Curved Lifting foil-- http://www.boatdesign.net/forums/sa...kind-performance-one-design-dinghy-39229.html

 

DSS, Infinity 36 and that new boat(?)

This is from a comment made by an associate of Hugh's-mostly about DSS and the Infinity 36, but there is a little tid bit about a pending announcement:

Hi, I have done a lot of miles (all of them) on the Infiniti 36, although not the second one and a lot of miles on the first test boat, the 27. There are some films here which pretty much show the boat sailing in most conditions. I have been working with Hugh on this for about a decade and where he is a very smart naval architect I am not..... my background is lots of miles on some reasonably sized boats. I still come back to the dock in awe of what Hugh has invented - no manner of talking or describing really does justice to the excellence and simplicity of what has been created. This is simply the biggest (sane) change in yachting for the average guy up to the extreme solo sailor in decades. We have developed this in an extremely methodical manner, never trying to run before we could walk and now, we are about to announce a pretty significant project, but we need to wait a day or two for that........ There are plenty of people who question how it works or indeed, if it does work but they are not people who have sailed on one of the boats! Hugh does an excellent job on this forum of answering technical questions but today he is traveling so it falls to me to try and answer the questions. Yes, we have a square top main, it is not excessive, around 22% for the top, this is nice as it is not too draggy and when we have a reef in the main the twin top mast backstays can both be set, so no need to worry about the rig. The bridle works very well, I was sceptical at first but Hugh was spot-on; only when racing the very, very light Palermo to Monte Carlo race did we need to run a hauler to windward. It is nice and light and simple. Yes, the vang is pretty powerful and when we are seriously wicked then it is the primary main sheet control. Otherwise the boat is the same.....but different. It is great fun to sail them all, especially when you consider the concept that the more speed you can derive from your skill/trim/helm/balance etc the more the foil gives you back.... the faster you go, the more the foil works. It is also worth noting that this is about the hardest size to "do" for DSS. There are a variety of reasons for this, and Hugh is best placed to explain but if you think that basically the faster the boat goes, the better the foils work.... so, a 36 ft boat is naturally slower than a 70ft boat... and therefore it is harder. The smaller boats we have done get away with this because of the racks and water ballast etc. So, to say we are very happy with the Infiniti 36s is a massive understatement, they, like all the boats have outperformed expectations - hope this explains a few things.

 

Quant 30(28)

This is a letter I received today from Michi:

For those who do not know: Geneva is one of the regions in Switzerland where sailing really is something that matters. This spot still is one of the more important locations worldwide, when it comes to lakeracing. So many innovations for lakeboats are rooting in Geneva or Lake of Geneva.

Positive proof that Geneva has a rich sailing-culture. Zurich – where i come from – also has a nice lake but hasn’t the same sailing spirit.

If now a sailor from Zurich, with a little unconventional sportsboat of just 28‘ manages to get into the fancy Bol d’Or-Magazine with two pics (see attachment) and a caption calling the boat „a sensation“ – then you are tempted to say: „We made it“! All the more as there are so many interesting and headturning boats fighting for recognition – most of them are much taller and most of them are Geneva based.

Line honours in the class and 7th monohull over all after more than 21hours of sailing is a good result after victory (both real and corrected time) in the rehearsal race the weekend before the Bol d’Or. The Q28 proved being not only incredibly capable for her size, but also is she relatively easy to sail and extremely simple to maintain and to move.

This is what we in Zurich are calling a real progress. The Q28 is clearly symbolising a new generation of sportsboats, fast, handy and and a boat for any passionate sailor.

My thanks go to everybody who made this possible, believing in Hugh Welbourn‘s DSS-System and Design and also in the QuantBoats-Lakeracer-Project – and especially to our sponsor „Allianz-Suisse“.

This letter also is the perfect occasion to announce that the former Allianz-Q28 has now found the right habitat:
A talented crew from the SNG is the new owner of this marvellous pocket-rocket and they now have to prove their abilities and skills, to make the boat even faster.

But don’t worry, our team will come back, trying to sail as fast as before but with a boat even simpler and easier to sail.

So please wait to welcome the new Quant30 – unluckily not yet sailready for the 75th anniversary of the first Bol d’Or.

See you soon and have a nice sailing season
Michael Aeppli & Max Schmid
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See here for more on the incredible race record of the Quant 28: http://www.boatdesign.net/forums/sailboats/quant-28-foil-assist-keelboat-dss-38421.html

Picture: the new curved, retractable(independently) DSS foil for the Quant 30:

 

What are we looking at price wise for the 30? tks.

 

Quant 30

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I don't know but when I find out I'll post it here.

 

Q30 price

hi guys
as soon as we finished the first 3 boats, we will go over calculation with the yard and doing kind of a pricelist for all further boats, also specifying what will be standard and what options. You can perfectly sail this boat with just three sails (main, jib, kite) and this will be the class standard in the future - i mean if there ever will sail more than 6 boats around the marks. this informations will be published on quant-boats.com but it still will take a month or two. Sorry