Evolvement of foiling sailboats over the last 70 years

It is a matter of public record that DSS has patented one of its designs. The phrase was used to distinguish that particular DSS foil design from its many others, nothing more.

 

Then perhaps referring it to....DSS foil etc...rather than a "patented" foil etc, floats my boat and is not a subjective confirmation of such.

I should say, I am biased. Since as a naval architect/engineer....i seriously despite the term...patented. It stifles creativity and further research.

 

=========================
You're partially right for "normal" DSS but not for full flying DSS which is based on surface piercing foils that also act as planing surfaces.
Normal DSS can work as a fully submerged foil, as a partially submerged surface piercing foil or as a planing surface:

 

===================================================
Apparent wind sailing is not new-that's how so many foilers can sail so much faster than the wind.
Moths can do 2-3 times windspeed , F50's probably 3-4 times windspeed ,iceboats up to 5 times windspeed.
-------------------
Just discovered this commentary by John Perry in the Artemis thread in the "Boatdesign" forum:
Press release: AC50 catamaran will do 20mph SOG against a 10mph tide in zero wind? - Amateur Yacht Research Society https://www.ayrs.org/phpbb/viewtopic.php?f=28&p=3527#p3527

 

====================
According to Hugh Welbourn both "normal" and full flying DSS are covered by his patent or patents.
--
I think the patent system used to be a valuable way for inventors to protect their intellectual property for a specific time. However, the cost of getting a patent has skyrocketed and the cost of defending a patent has become ridiculous. In many respects patent coverage is now only available to wealthy big companies.

 

I was not aware that the UpTip foil was intended to be flown with the tip above the surface. My understanding is that this is a slow way of achieving ride height control because (1) you get additional drag and (2) air may/will be drawn down the low-pressure side of the foil moving it out of its design envelope.

I would disagree with the statement above because the thing that makes UpTip clever is its "passive" control of ride height. I don't believe any implementation of a surface piercing V-foil is attempting to use leeway in this manner; thus their operating principle is different. The physical similarity is merely coincidence; note for example that the angle between the horizontal and vertical elements of an UpTip foil will be less than 90 degrees, whereas on a V-foil you would expect 120 degrees or more. It is true though that any angled foil that progressively leaves the water as it rises will see a progressive loss of lift and will therefore act as (and be) a surface piercing foil in that circumstance.

The leeward foil seen on IMOCAs (e.g. Charal in post #33) is much closer to the traditional V-foil, just cantilevered out rather than on the centreline of the vessel. The use of foils on either side developing unequal lift and therefore righting moment at non-zero heal (e.g. IMOCA, Quant 23) is also not really new, though the implementations that use a wand on each hull each connected to a trim tabbed T-foil are quite innovative. I think this is the only current way of achieving active heal control without surface piercing foils.

 

You must consider every foil ever used on every boat ever to be "technically" a surface piercing foil, as at some point, at some attitude of the boat, they will be only partially submerged. Even T foils.

Surface piercing is typically used to describe a foil where changing the level of immersion is a fundamental principle of its operation, usually to control ride height but not always. If applied to every foil that happens to breach the surface from time–to–time, it would include a traditional centerboard, reducing the term to meaninglessness.

 

=====================================
According to Tom Speer, letting the Up "tip" breach the surface is slow.But according to Martin Fischer and others it is not(significantly). The picture of the GC32 with it's up "tip" showing was going faster than any GC32 had ever gone. You frequently see the tip on many cats and tri's with UptiP foils-that doesn't make it the best way but it's just the way it is. See Gitana Mod 70 pix below.
I don't think that is correct-take a look a Doug Halseys foiling tri with "V" foils. The angle between the two foils that comprise a "V" foil is less than 90 degrees on every one I've seen .
My Fire Arrow and WOLF use two altitude control systems simultaneously: 1) as part of the lee ama UptiP foil and, 2) a wand controlled foil on the daggerboard. The wand controlled foil sets the flight altitude of the main hull while simultaneously determining the angle of heel of the whole boat while also working with the rudder T-foil to control pitch of the whole boat. The wand controlled main foil automatically develops downforce as required......
The 100' tri's and Maserati(that also use two altitude control systems simultaneously) control the heel of the whole boat by changing the angle of incidence of the main foil(on the daggerboard) manually with an electro-hydraulic system (exactly what Fire Arrow/WOLF do automatically with a wand controlled main foil.) The big boats will eventually use a flight control autopilot that will adjust all the foils as required but most frequently the mainfoil on the daggerboard. As of right now such a thing is illegal in the Ultim class. But Gitana 17 is already set up for that system when it becomes legal.

Doug Halsey's foiling tri "Broomstick" with "V" foils:
Terry Curtis photo--


Gitana Mod 70(later Maserati) Uptip ama foil breach of tip:
---- photo by Team Gitana

 

Doug Halsey posted last monday the below picture of him and his boat Broomstick on the thread: Man is regressing (not about foiling) → post #12



See also the threads: Surface piercing hydrofoil (2010) — Foiler Design (2003)

 

There's a subject thread about the Artemis video about going upstream the Amazon on a windless day.

 

Now I was thinking, what happens if you leave the windward foil in the water, but transfer that foil into a downward force, wouldn't the boat be able then to carry more sail area and go faster . . ?

 

It appears to me that vertical lifting foils are the last word in sailing performance. I have never seen so much invective spewed at a newly introduced sailing technology since multihulls were introduced in the 1960's. IMHO, like multihulls, foiling sailboats are here to stay. I would certainly like to get a ride on one. But owning one would probably not be my thing. Fast sailboats of all stripes tend to have limitations of their own, usually: limited payload, higher cost per displacement, higher levels of complexity, and ofter longer set up times.

 

To my understanding, being granted a patent means nothing more than the paperwork was correctly filled out and a cursory inspection of the idea does not reveal it to be unoriginal.

I would have described the foil in some other way if I was aware of a discrete name for it. As far as I know, all foils designed by DSS (and many foils that are similar but not by DSS) are referred to as "DSS foils". I first came across them when our Ross 780 almost T-boned a skiff with them (Brace Brace Brace), they were just called "DSS foils". The ones on the Quant 23 are sometimes called "Quant 23" foils. They're also used on the Quant 17. Perhaps they can be called the "DSS laterally sliding midship wing foil with little or no curvature"? Or maybe just "DSS v1" and the Quant 23 style foils can be "DSS v2"?

 

DSS (Dynamic Stability Systems Ltd), a granted patent that showed up right away . . .

Patents Assigned to Dynamic Stability Systems Limited

US Patent Application for Monohull Sailing Vessel having a Lifting Hydrofoil (Patent Application #20090283023 issued November 19, 2009)

US Patent for Monohull Sailing Vessel having a Lifting Hydrofoil (Patent # 7,644,672 issued January 12, 2010)

 

DSS (Dynamic Stability Systems Ltd) patent US 7644672, patents.google.com gives better me better info plus 23 drawings, also available as PDF.