Why no performance specs for new sailboats?

Discussion in 'Sailboats' started by Claus Riepe, Sep 5, 2007.

  1. Claus Riepe
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    Claus Riepe Junior Member

    Clearly, nobody of us would buy a new car without the manufacturer giving us some reliable info on the top speed and fuel economy of it first. Consumers rights, so to speak.

    But with new sailboats, no such info seems to be given, how fast she sails at different angles to the wind, or what is the angle of vanishing stability.

    Just giving the CE category is not enough, especially when you know how differently boats can be tested for that - or never actually are tested for that.

    About time sailboatbuilders must publish some detailed performance info about their products? What about consumers rights for sailboat buyers?

    Claus
     
  2. Guillermo
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    Guillermo Ingeniero Naval

    I absolutely agree with you, Claus, in the necessity of a clearer and deeper info on boats characteristics and expected performance to be provided by manufacturers.
    But problem is most users don't care a damm thing about it. If buyers begin to demand more info, manufactures will finally provide it (even if reluctantly in many cases!).
    Cheers.
     
  3. Claus Riepe
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    Claus Riepe Junior Member

    Guillermo,
    thanks for your support. We often meet sailors at races who are -in many cases- bitterly disappointed when they realise how poorly their new boats perform when in direct competition with other peer boats of similar looks, sizes and sailplans.
    Especially within the 'traditional looks' group of sailboats there are some surprising differences in performance.
    Often buyers are made to believe that poor sailing performance is a necessary side-effect of 'traditional looks', Bollocks.
    I think publishing performance data of new boats would help competition and help up the market, not damage it.
    C.
     
  4. Vega
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    Vega Senior Member

    Some manufacturers publish on their advertising a Polar diagram of speeds. If you ask most of them have the information available and will give it to you, but most manufacturers have plenty of options for their boats, many with implications on speed, so watch out. Quality of sails, draft are paramount for speed and can make a huge difference on apparently similar boats.
     
  5. Mychael
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    Mychael Mychael

    In another thread along similar lines it was suggested that another reason (not the only reason) that manafacturers do not publish complex or complete performance data for their designs is that a lot of your "man in the sea" (as in "man in street") type sailors would not understand all the complexities of the data.
    Speaking for myself I get all glazed eyes when I try to follow some of the more technical discussions that the more learned members engage in here from time to time. Some of it goes right over my head. (and I'm not even English, Scottish or American) lol. sorry guys just had to toss that in. ;-)

    Mychael
     
  6. Claus Riepe
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    Claus Riepe Junior Member

    Mychael,
    good point. The data must be understandable i.e. practical enough to be digestible.
    The AVS (measured using the ISO method) would be pretty clear, and one diagram or list of values showing the time required to travel one nm directly to windward, reaching (90degrees off the true wind) and to downwind, with standard equipment and sails, and with minimum permissible crew, in several (at least three) different wind conditions. All that can be done very easily and reliably with just one anemometer, one GPS and one witness.
    Any better ideas, anyone?
    C.
     
  7. messabout
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    messabout Senior Member

    Claus:
    You have made a some good points about the absence of information for sailboats. As for potential speed I think that supplied information would not be entirely accurate. For example, one Nm to windward can be done much faster by one sailor than a different sailor. I have proven this many times in one design regattas. I am a middle of the fleet sailor and have sufficient experience to know that some skippers have seemingly magical powers while others do not. Yes I am good at tacking to lifts, observing the advent of oncoming puffs and lulls and all that sort of thing. No matter! There are skippers who can wring extra distance made good from a boat identical to mine. In recognition of that reality, I think the manufacturer would be inclined to omit speed predictions from his sales literature.
     
  8. Mychael
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    Mychael Mychael

    I think the manufacturer could supply some speed data for (expected performance in optumum conditions). After all car makers quote economy figures but how many of us have actually achieved them in the real world.
    It would still however give as some baselines for comparisons between designs and I'm thinking that stabilty figures could be quoted, again even if it was stated as being with 50% weight payload, standard rigging etc. It would still give usefull data for inherent hull safety margins.

    Mychael
     
  9. Claus Riepe
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    Claus Riepe Junior Member

    Messabout:
    Mychael has made a good analogy. Even though the fuel economy figures given by the car manufacturer cannot -ever- be matched by real people in real road traffic, they still are informative and even reliable in the sense that they sort different cars into a certain order with regards to fuel economy. Also individuals can loosely predict their own fuel consumption from them, through adding -say- 12% to the manufacturers figures.

    Your concerns are valid too, but they should not put us off altogether from the objective. To compare sailing boats with regards to their performance may be a tall order, but a very desirable one. Let me just remind you of the long standing Yardstick system.

    Yardstick was developed long before the advent of the GPS, which today would make measuring sailboat performance a snap. Anyone can check the VMG (Velocity Made Good) of his boat today through just pressing a few buttons, and even produce a measurable printout of the track the boat has sailed as proof.

    Hey, come to think of it, the VMG could be a universal and comparable -even repeatable- performance indicator for sailboats, and be a better basis for a New Yardstick system of the future.
    Agree?

    Claus
     
  10. yacht371
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    yacht371 Yacht Designer

    There is a simple way to get a good idea of a boat's performance. Many yacht clubs which hold races under PHRF ratings publish then on the net. The lower the rating number the faster the boat. For example a J-35 rates 75 (pretty fast). A Westsail 32 with about the same waterline rates 213. The rating is in seconds per mile, so it means the Westsails is expected to be about 138 seconds behind after just one mile of sailing.

    While not exact this gives a very good indication how the boat you are considering compares against other boats of similar type.

    Ratings for new models may be a bit misleading. A Hanse 371 and a Beneteau 373 rate close to the same, but I know from personal experience that the Hanse is MUCH faster.
     
  11. Claus Riepe
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    Claus Riepe Junior Member

    Yacht371:"... For example a J-35 rates 75 (pretty fast). A Westsail 32 with about the same waterline rates 213. The rating is in seconds per mile, so it means the Westsails is expected to be about 138 seconds behind after just one mile of sailing. ..."

    Interesting link, though no J-35 can race a mile in 75 seconds, nor a Westsail 32 one in 213. The PHRF ratings need to be adjusted by a time constant which depends on the average wind and race conditions. But your result is correct, after a mile of sailing both boats would finish approx. 138 seconds apart.

    However, Yardstick and PHRF are pretty much secondary empiric ratings, computed, compiled and adjusted only for boats that are frequently sold and raced, so these ratings do not come automatically for every new boat coming to the market, and at the time when it is coming to the market first. So they are not a solution to the problem.: What I am trying to find favour for is that all sailboat builders must publish realistic performance data right at the point of sale. They must testsail and measure their boats first and then display the key performance data alongside their asking price.
    For me, the single most essential performance data of a sailboat, and the one most simple to measure and check, is the VMG.
    So again, why don't they all display it yet? Shy?
    Claus
     
  12. Munter
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    Munter Amateur

    There are so many variables in sailing that getting a consistent set of data to allow comparison would be fairly difficult.
    Do you just measure steady state speed or try to include some kind of analysis of dynamic effects as well? What sort of conditions get chosen to represent the baseline?
     
  13. fcfc
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    fcfc Senior Member

    You forgot one thing.

    Who will PAY for these data.

    For car you speak in your post, the condition of measure for pollution for instance, are in a near 300 pages document precising ALL parameters. From ambient temperature to road contact to fuel qualitity to atmospheric pressure , hygrometry, and any inimaginable thing. The fact is that if you repeat the measure by ANY independant laboratory, of course in the same specified test conditions, you find back the original figure. You then have trustable data you can use for comparison because all manufacturers do the same test.

    For boats, unless you make the test in a test basin coupled with a wind tunnel, all at real scale , with everything controlled, your figures wont be reliable. (air temp, hygrometry, pressure wont be same, wind gust , salinity or water temp , wave profile , depth effect, etc etc). How could you compare the performance of a boat, one sailing in greece, the other in norway ...

    This repeatable laboratory measurement has a cost that a car manufacturer can spread among hundred of thousands cars made a year. I doubt sailboat buyers will agree to pay their boat 5x more, just because the laboratory test costs have been spread on the only 50 units of the serie.

    And if the published figure is not repeatable or cannot be independantly verified replaying the same test conditions, it is just useless marketing ********.
     
  14. jim lee
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    jim lee Senior Member

    yacht371:
    This is the -first- thing we do -every- time we look at a boat for sale. One of my friends showes up; "Hey I found a boat for sale.." And we all gather together over the PHRF list. Then its: "Eww fast!" Or "Eww!! It sails like a bouy!"

    Using PHRF is such a great way to get an instant idea if a boat's a slug or not. It avarages all sorts of sailng conditions, boats and people togather. Then boils it all down to a simple number. I always wonder why more people don't look at these numbers beore looking into buying a certan type of boat.

    P.S. J/35 rates 72 ( And boy is it fun to sail! )

    -jim lee
     

  15. Claus Riepe
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    Claus Riepe Junior Member

    No, I did not forget that.: The BUILDER must pay for that.

    But you were not listening: To measure the VMG costs near to nothing. If the builder chooses to cheat, he will be found out by the PHRF guys, free of charge for him (except of course for the resulting face-loss).

    Because, PHRF rating and VMG are interconnected, you can re-compute PHRF into VMG and vice versa VMG into (upwind scenario) PHRF quite easily.

    I think you were just trying to stall the proposal through over-complicating it. We all know sea and wind conditions differ greatly. But there is such a thing as averaging, like they do it for the PHRF rating (or Yardstick). Common sense.

    Jim Lee:
    Thanks for your comment, very constructive. Yes, if performance data are available, people will use them. Good for the user, bad for the poor performers, excellent for the quality of the market overall.

    C.
     
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