Hull Efficiency today vs. 25, 50 and 100 years ago?

Discussion in 'Hydrodynamics and Aerodynamics' started by AndySGray, May 15, 2015.

  1. TANSL
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    TANSL Senior Member

    Gonzo, are we talking about designing ships, or selling boats?. The difference is obvious, but in case someone does not know, I have to say that these are two completely different professions. I've never sold boats and therefore can not comment on the preferences of these customers. As a designer I can say that would make me laugh a client asking me to design the ship, with a certain "capacity" (according to what you mean by capacity), to pay less in a marina. Not least because rates of different marinas can change a lot and a boat "optimized" for a marina would be totally inappropriate for another. And, I suppose, any customer may be interested in docking at various marinas. Also, for a seller of boats, it might be interesting to sell his boat on marinas with different rates.
    I think you have not thought much about the marinas price argument. I do not think you say that so convinced of what you say. It does not seem serious and, of course, is unprofessional for a boat designer.
     
  2. philSweet
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    philSweet Senior Member

    Not really. There are recommended best practices for the proportions of boat slips.

    https://marinaassociation.org/sites/default/files/free-resources/design guideline for marinas 06.pdf

    Its a bit of a conundrum as to whether marinas are designed to fit boats, or vis versa, but there is certainly a strong motivation to use all of the slip. Marina fees are the most obvious large and unavoidable cost of ownership, so boat designers are very concerned with this aspect of design. Yacht appearance when slipped is also a big design and styling issue. These are probably the big drivers of the trend to wide sterns on yachts. Impressive in the slip, but sometimes butt-ugly on the water. Yachts are often shifted between marinas by professional crew without the owners aboard. The owners returning aboard when it's safely in its new slip.
     
  3. TANSL
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    TANSL Senior Member

    In my country there is no "recommended best practices for marinas". Each "Club Nautico" imposes its rules and I can say that the most expensive are not their rates (although not cheap). A boat, in my country, has other associated expenses that make the price of marinas are not the most important. And, of course, designing a boat, thinking on these prices, to me, it seems like a huge blunder.
    Of course, a very high % of pleasure boats that are in the marinas of my country have been designed without knowing what marina they were to dock and, of course, marinas prices. But perhaps here we are something "weird".:p
     
  4. pogo
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    pogo ingenious dilletante


    1911
    Saurer-Lürssen speedboat holds inofficial record; 32knots.
    http://amuraworld.com/images/articles/100-especial/076-astilleros/080-bote.png
    Lürssen-Daimler speedboat wins trophy in Monte Carlo; average 27knots
    Lower Pic :
    http://images-00.delcampe-static.net/img_large/auction/000/287/037/059_001.jpg


    1927
    3 Maybach engines , each 480HP, push 70' " Oheka II " up to 38knots
    http://www.fky.org/prestodata/showdoc.php4?doc=seite&heft=39&jahr=1927&seite=22&b=s
    http://www.fky.org/prestodata/showdoc.php4?doc=seite&heft=39&jahr=1927&seite=23&b=s

    pogo
     
  5. gonzo
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    gonzo Senior Member

    I have been in Spain, and they charge by the meter as in the rest of the world.
     
  6. TANSL
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    TANSL Senior Member

    And who says otherwise ?.
    I live in Spain and here there is no boat designer that takes into account the rates of marinas to define the dimensions of his project. What a nonsense!
     
  7. gonzo
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    gonzo Senior Member

    You said it in post #18. Consider having your memory checked. You often post and then contradict yourself.
     
  8. TANSL
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    TANSL Senior Member

    Sorry Gonzo, once again I have to say that it's not true what you say. Here is my post # 18 for anyone to read what I have written.
    But the issue that I comment is not whether fees are paid or not paid, what I say is that to affirm, as you assert, that a designer designs his boat considering, or having in mind, the rates of marinas, is a big blunder.
    That's all, and be happy my friend.
     
  9. gonzo
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    gonzo Senior Member

    It is not a blunder if it sells.
     
  10. AndySGray
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    AndySGray Senior Member

    Was a fine vintage and great company and seemed like just the right amount at the time ;) :D
    (perhaps less so the following morning:( )


    Thank you very much for your excellent explanation
    It has really helped me make a lot more sense of it all

    :)
     
  11. AndySGray
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    AndySGray Senior Member

    Thanks, yes that's a very good point, the guys back in the day were working within a very different range of performance - a modern power-train is physically similar in terms of size and weight, but offers significantly more power. So an older design may be just as good over it's given range of design parameters as a modern hull over its (wider) range - we need great care if we try to superimpose a modern set of performance expectations on an older hull,

    Ah, walking the tightrope of compromise - Just because 'the customer is always right' doesn't mean he isn't a pain in the behind.:D
     
  12. PAR
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    PAR Yacht Designer/Builder

    In the early years of power craft, HP was heavy. A 50 HP engine might weigh a ton, so they placed it in a slender hull to get as much out of it as practical. As HP/weight ratios decreased, boats got fatter, simply because they could afford it. This is especially true in the USA, which has dominated the pleasure boat market, in terms of design trends and where fuel cost have been traditionally low. This isn't to say there aren't other influences, but is to say, if you're a pleasure boat builder and want sales, you better service the biggest market. It's only in the last few years that markets other than the USA are becoming influential enough to drive the major trends, but lets face it, you design to suit the USA market and hope for the best in the rest. This means fat, high HP pleasure craft, lots of tankage, berths and plenty of square footage for scantly clad teenagers.

    Yes, pleasure boat designers do think and scale yachts to the dock fee and related length limitations, typically imposed. This is why there's so many 33' yachts and also why some areas have developed 36' boats with retractable bow pulpits (the med, Great Brittan, etc.), so they can park at the shorter dock. On custom yachts, this is a major consideration in smaller sizes, though larger yacht commissions typically don't have as much emphasis on it, mostly because they can afford a 50' slip for their custom yacht.

    Tansl, ships are working vessels and designed to function. Styling, market share and acceptance aren't particularly high on the priority list, as you work around the spiral. This is just a simple business decision, as function and return on the investment are the only real drivers.

    The customer is never right, just opinionated, full of themselves and has enough money to desire a custom. The wise designer keeps this in mind continuously, or is quickly screwed to do something they're rather they weren't forced into. The very reason they come to a professional is because they're not correct, nor capable. It's the professional's job to diplomatically point out their misunderstandings, misgivings and other "insistence(s)" and more importantly offer the solutions to the "issues" they've previously thought where settled. Folks experienced and well off enough to consider a custom, are usually also intelligent enough to accept that the "pro" might be right. You don't win all of these debates, but you do try to win the important ones, knowing from you "read" on the client, what they really need, instead of what they think they need.
     
  13. TANSL
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    TANSL Senior Member

    I think a designer, simplifying things, can receive two types of orders, from a client who wants his personal ship and from, lets say a factory, who wants to build hundreds of units of the same model.
    The first client who wants a boat "tailor made" cares little marina rates. The second client does not care those rates.
    For a seller who wants to sell a boat already built, and more in times of crisis, there will be a type or a size of boat to sell more and better than another. But this is a circumstance that has nothing to do with the parameters that a designer has in mind when projecting the boat. As I said earlier, one thing is to talk about the sale of ships and another the ship design. This is my opinion and what I'm trying to explain. I am not a seller and therefore I can only comment about "sales". Those who are not designers should not talk about how the boats are designed. Naturally they can hold and express their opinion but, if they are wrong, should recognize.
     
  14. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I think you'd need to include a few factors such as seaworthiness of the hulls so you are comparing apples to apples.

    Start out with certain length and displacement, then require a max amount of rolling/heeling or whatever when encountering a certain standard wave config from a certain direction at a speed they can both achieve, THEN compare efficiency.

    I'd guess many older hulls had to be more inherently seaworthy due to lack of good weather reports, and especially lack of Coast Guard rescue helicopters.:eek:

    I'm also guessing they were designed to be more soft riding, partly due to heavier engines and materials, but also customer preferences. Old Money VS Drug Cartel honchos or Young Geeks.
     

  15. Rurudyne
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    Rurudyne Senior Member

    In the older yachts they also may not have been carrying so much in the way of heavy luxury touches that really do little by but look good: like stone countertops or marble sheathed bathrooms.
     
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