Design for DSS-Foil Assist for Keelboats

Discussion in 'Sailboats' started by Doug Lord, Dec 6, 2011.

  1. ancient kayaker
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    ancient kayaker aka Terry Haines

    That pretty much summarizes my concern, a given DSS configuration in a relatively narrow range of conditions provides advantages that vanish when the conditions go outside the range. Still some learning to be done . . .
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Dss

    ==========
    I would not put too much stock in the SA quote in terms of realistically analyzing the effectiveness of a DSS foil in any conditions much less specific conditions......
    --
    The 40% speed increase referenced is just nonsense-either misrepresented as the standard predicted speed increase for DSS or just made up. A full flying foiler could conceivably offer a 40% speed increase but the only way DSS could do it would be in certain specific conditions-light air flat water maybe*. If anybody finds any DSS document that claims an overall 40% increase in speed in any or all conditions I'd like to see it.
    Lets see: 1.4 X 7=9.8 ; 1.4 X 9= 12.6.......interesting.
    If a 40% increase claim for DSS overall is not specifically written by Hugh Welbourn, it is nonsense. Most likely, it is a statement taken out of context <innuendo about competitor removed> BBB and the Quant 28 have shown great speed in racing and soon there will be two Quant 30's and the DSS Mini and a 50 footer with DSS.
    -----
    * This is specifically in reference to BBB(and Quant 28 for that matter) where a lightweight, planing sportboat is sailed with DSS in marginal planing conditions. The foil helps to initiate planing earlier than on the same boat w/o the foil so on this type of boat the speed difference between foil/no foil would be potentially very great in these conditions.
     
    Last edited: May 29, 2012
  3. Doug Lord
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    Doug Lord Flight Ready

    Dss

    From Quant 28 on SA:

    Posted 05 July 2011 - 07:10 AM

    Hi guys

    40% faster in all conditions and all courses is something nobody said from the side of DSS or from our side. Thats complete ********. But there was a race i described shortly (in my swinglish) on my website www.quant-boats.com (see news and scroll to the race from ascension day). This was a race more or less in favor for the concept of the q28 or good and well balanced DSS boats in general and there was almost a 40% advantage (we sailed 85m the second about 18min or something) over a bigger and also quite fast boat with trapezes, big reaching headsails etc. although i was sailing badly and also having had bad start sailing through the whole fleet.

    The guy with the T8 (t-8)? is absolutely right: up & down races today do not have to end with a DSS boat winning in every circumstances, geografical races may end with a bigger number of DSS wins even today, if you look at the results of several race. The reason: if you have the chance for reaching or downwindsailing fully on the foil just for maybe 15% of the time of a race you are that much faster than normal comparable boats - you may win (line honours - rating is other stuff again) but i think BBB is not sailed very well and this boat is maybe a bit more complicated to sail compared to the Q28 which is also 1m longer.

    A word to trenace: yes the boat i was talking in my blog (race of ascension day) was the Esse 990. i didn't compare our boat with this one. i just described the situation, when we passed this boat in a gust on leeward side (distance may 15 to 20m). i was completely suprised that there was not the slightest influence of this bigger boat on the Q28 - maybe because we passed this boat that quickly. the owner told me afterwards (he was really very surprised also) that he went along with about 8 to 9kts bsp, we passed him with about 15 to 17 kts. after passing the Esse, the mark was about 600 m away - with the help of this short gust we lead over the Esse with about 250 to 300 m! that was impressing everybody - because you didn't see such a thing before. it was more like a catamaren passing a monohull.
    But again: In one of the races on lake of Geneva we lead the fleet of the monohulls in light but quite stable conditions for a while against 45 footer (14.2m) with mast 2times longer than ours or even more. We ended up 6th or 7th boat (sailed time) after sailing for some 6 or 7 hours, corrected 2nd in the class, 2nd over all monohulls. and again, not one time really on the foil, no conditions in our favor not at all. the q28 is a very good boat and a huge step in development - and it can profite from DSS from time to time. just to let you know: A normally well sailed T-boat with canting keel, trapezes and stuff lost 1.5 hours on us in that race. any questions? and yes this guy is going to buy my boat end of season - as it looks and if i let him have it:) and the best thing: it was a huge up and down race - and the reason we couldn't win against the big boats in the end. Ask Kos, he sailed with us - so did Hugh.

    If it comes to normal upwind sailing in decent conditions our boat goes really very well, but it is 8.5m and its physics: It won't go much faster than any other comparable modern sportsboat, it will be the crew, the sails, the tactics etc. Downwind you may have some advantage because the boat is quite light, thanks to DSS...but it also stops much quicker than heavier boats and if you really know lakesailing, a bit of weight is not bad sometimes. look at the esse 850 the boat may be a bore but it is quite effecient - maybe not on Moreton Bay but on lakes, even on Lake of Garda.

    What i wonder: How much experience and understanding do you have of real lakesailing - like we do it most of the time? You all maybe have to think about that first, if you want to juge what we are doing with the Q28. In 80% of the time we sail in about 4 to 7kts of wind. if wind is that weak, it is also very unstable (shifts, patches, puffs, holes with zero etc.). the bigger the boat the better! There are always lots of valleys and mountains around, also trees on the shore etc. Looking at such a racesituation is also a reason, why you shouldn't compare boats too much after analysing one race or two or comparing just the potential of the boats. In lakeracing like we do it as amateurs and you have to have a look over the results of a couple of seasons - then you see its a game between sailors&crews and not only boats. Just as an example: last year i won the annual championship with a Longtzein the racing class - the smallest boat by far - the same Libera (you already know) came second. Of course they should have won - we sailed cleverly and had some lucky punches. i do not say this is how lakesailing is all the time - but it can happen if you know what you are doing.

    This whole discussion sucks a bit: Please let us have some time to learn to sail DSS boats, to develop the suit of sails properly, how to jibe how to tack etc. - i can tell you it is not that easy - if you are not a professional, a sailmaker or something. i am just a guy that have to sit in his office during the week also my friends sailing with us. And therefore we need more time to experience the new Q28. OK?

    have a nice day and cheers from sunny Switzerland
     
  4. ancient kayaker
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    ancient kayaker aka Terry Haines

    Doug: As far as I know the only reference to a 40% improvement was for RM not speed in your post #46, until Sean9c quoted Steve Romagnino in post #135 who created the 40% speed myth as far as I know. I assume Steve did an on overly hasty reading of somebody’s words . . . I doubt anyone gave it much credit; at the time I assumed it was a typo.
     
  5. Doug Lord
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    Doug Lord Flight Ready

    Dss

    ==================
    Terry, I researched this and found the Quant 28 refutation of the 40% across the board "claimed" speed increase which was first brought up by a guy by the name "Trenace" in the "Whats this" thread on SA(see #2 below) where it was soundly refuted by Q28. Then, in another thread "JS 2000going to weather"( see #1 below) or some such, the same claim was reposted by this "Trenace" character who refused to document where he found such a claim. Subsequently, in the post from SA quoted in red on the previous page, "steveromagnino" used the 40% speed increase again by saying that it sure didn't look like BBB was making a 40% increase in speed.
    When BS hits the net, it begins to have a life of its own as has this rumored "40% increase in speed with DSS".

    ---1) Thread quoted on previous page: http://forums.sailinganarchy.com/index.php?showtopic=32448&st=125 post 149; also the "Trenace" character brings up the "40% more speed with DSS " again after being chastised by Quant 28 in 2) below and quoted in its entirety in post 138 of this thread.
    --
    ---2) First mention of "40% greater speed with DSS" claim(unsubstantiated) by "Trenace" : http://forums.sailinganarchy.com/index.php?showtopic=122886&st=200 June 2011
    post 116
     
  6. Cheesy
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    Cheesy Senior Member

    Doug, why do you say that Steveos account of the performance of BBB in those conditions should be discounted? It seems to be a reasonably balanced take on it, BBB is quick in flat water in 10-12kts, the Shaws (which he produces and sells) are quicker in almost everything else. It makes sense that on a light boat the DSS foil can and will come out of the water with any sort of wave action.


    edit: Maybe the 40% number came from publications like this...

    120 degree True Wind Angle (TWA) – performance summary:

    Percentage performance increase at 120’ TWA delivered by DSS is from 1.2% at 6knots of wind speed to 44.2% at 25 knots of wind speed

    This equates to being 0.14knots faster at 6 knots wind speed and 7 knots faster at 25knots wind speed

    The DSS powered Magic Carpet is always faster than the standard Magic Carpet

    90 degree True Wind Angle (TWA) – performance summary:

    Percentage performance increase at 90’ TWA delivered by DSS is from 3% at 6knots of wind speed to 39% at 25 knots of wind speed

    This equates to being 0.3knots faster at 6 knots wind speed and 5.7 knots faster at 25knots wind speed

    The DSS powered Magic Carpet is always faster than the standard Magic Carpet
     
  7. Doug Lord
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    Doug Lord Flight Ready

    Dss

    ===========
    It makes no sense at all given the first hand information I have on DSS and on this boat. Comments like that that purport to introduce a technical explanation/hypothisis for "why the foil doesn't work" in "big" conditions are just nonsense.
    --
    "Trenace" claimed that DSS advertises a 40% increase in speed across the board in all conditions at all speeds which is nonsense-but was picked up as "fact" by the "Stevom.....".
     
  8. Cheesy
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    Cheesy Senior Member

    No Stevo said he didnt see a 40% increase of speed on any point of sail, his account was also first hand but should be discounted because?
    a: it is not completely favorable to DSS
    b: he sells Shaws

    It should also be pointed out that BBB did actually beat the Shaws on line in several of the races.... just for a bit of balance
     
  9. Doug Lord
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    Doug Lord Flight Ready

    Dss

    ==============
    Maybe it did-if so it is an egregious misrepresentation of the facts since those numbers were quoted from a study Welbourn's team did for a 94' Wally! But based on what "Quant 28" said above there is a possibility that such speed increases can occur in certain conditions even on smaller boats. But it's nonsense to suggest that DSS, Welbourn or anybody else "claims" a 40% speed increase for any boat using the technology.
     
  10. Doug Lord
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    Doug Lord Flight Ready

    Dss

    =================================
    It should be discounted because he doesn't know anything about DSS design, has no experience on a DSS boat, and because he used a false claim to suggest that the DSS boat was performing poorly. Further, with all the variables in any racing sailboat, this guy narrows the problems of BBB down to one thing: the DSS foil! Arbitrary, uninformed, nonsense........
     
  11. Cheesy
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    Cheesy Senior Member

    What was the false claim as to the boats poor performance? the 40% bit? that is completely irrelevant. How about the fact that BBB is faster than the Shaw 650 in a certain range of conditions and not in others, that seems pretty straight forward, then if you look at the numbers (sail area RM etc) BBB should be faster than the Shaw all the time, let alone comparing it to a Shaw 750.

    As an added preemptive point, the Shaws do not have the ability to reef the main, in fact almost no fast sport boat does as the rig will no longer offer any automatic gust response, no back stays either
     
  12. Paul B

    Paul B Previous Member

    This thread gets funnier by the day. <insult directed towards another member removed>

    This shows he doesn't even understand the "technical proof" he posts. The chart he included in his post #110 of this thread clearly shows the claim of 40% speed increase is not in light air, but in breeze.

    How could <insult directed towards another member removed> make such a mistake?

    <insult directed towards another forum member removed>


    The Shaw being mentioned is a much smaller boat (about 20% smaller) that the Brace^3. Yet the Shaw doesn't seem to be 20% slower in any condition where the gizmo is deployed.

    There certainly is no proof anywhere in the real world that the gizmo makes any boat 40% faster on any point of sail in any condition.
     
    Last edited by a moderator: May 29, 2012
  13. CT 249
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    CT 249 Senior Member

    So claims made by Shaw marketers can be dismissed because of commercial bias, but claims made by DSS marketers have to be believed despite their commercial bias?

    We have a DSS marketer who is happy to call a competitor (the Esse) "a bore" and yet a Shaw marketer is accused of dishonesty when he makes a remark about BBB....double standards abound!


    MESSAGE TO THE MODERATORS

    If you are willing to edit personal attacks on posters here, shouldn't you also edit personal attacks on people who post elsewhere like Steve M?

    Doug has claimed that Steve (who I've had many a debate with and never once found to be anything but honest) is coming up with false claims for commercial reasons. Why is such slander left unedited when comments about the slanderer are removed?
     
  14. Boat Design Net Moderator
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    Boat Design Net Moderator Moderator

    CT249 - I did not see a reported post in this thread other than the one above - please click the "Flag for Moderator" on the namecalling, insult, or slanderous remark you are referring to. Thanks.
     

  15. CT 249
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    CT 249 Senior Member

    Thanks Mod, I didn't do that because the "report" tag seemed to be for remarks made personally to a poster here, rather than about a third party.

    The statements I was referring to include;

    "most likely it is a statement taken out of context by someone deliberately trying to denigrate the technology. The SA poster is closely associated with a competing brand of sportboat and it is no surprise that he would make the uninformed comments he has made." and "he used a false claim".

    Steve M is a big boy who can take care of himself, but to have Doug sit at his keyboard and accuse someone else of lying does nothing but bring down the level of this forum.
     
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