choosing designer / naval architect

Discussion in 'Boat Design' started by ViennaYachtworx, Aug 25, 2010.

  1. ViennaYachtworx
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    ViennaYachtworx Junior Member

  2. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    The RIB in the video is a small tender possibly weighing some 70-80 kg. The Dommen's CAMUS (white boat) is apparently running in a high semi-displacement or in a low planing mode, but I was unable to find any technical data about that boat, apart the claimed maximum speed of 12 kts.
    The key figure for a planing boat is weight. A low weight flattens the hump in resistance curve and makes for a smoother transition from displacement to planing mode. All of these boats are clearly very light (and therefore very spartan inside), but how much? We can't see that data in the videos.
     
  3. ViennaYachtworx
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    ViennaYachtworx Junior Member

    Dear daiquiri,

    Thank You for taking the time to answer our dumb questions.

    According to you, what is the weight limit we should aim for?
     
  4. daiquiri
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    daiquiri Engineering and Design

    They are not dumb at all. We are talking here about the region of low planing speeds, a borderline for reliable calculation methods.

    My educated guess would be:
    Between 250-300 kg, lower is better, plus a carefully studied hullform and mass distribution, plus a more efficient prop.

    Now that I've looked better at HJS's boat in the previous page, it has the right proportions to reach the goal but the total weight should be lowered by some 50-60 kg, imho.
     
  5. Alik
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    Alik Senior Member

    I believe that planning is not best mode for electrical motor :)
    Make boat longer and slim...
     
  6. daiquiri
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    daiquiri Engineering and Design

    I agree. The weight constraint can be relaxed and the boat can be made more comfortable and with a more pleasant aspect, imho.
     
  7. Wavewacker
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    Wavewacker Senior Member

    Ooops, sorry! There is no mention as to any range requirements.

    Daiquiri, I guess a hydrofoil design from the 70s is not considered classic, just old. lol. You're right.

    There is Electraboat (I think that's right or close) it's a classic looking picnic style. Another looks like a little steamer. I read somewhere that electric hydroplanes hit over a hundred mph and go about a mile, then they are dead in the water. I have heard that if your boat is a battery, it might be feasible.
    I'd love to have electric power, but I would never have a boat that big. I thought running a genset would do it, but not after reading from the experts here and in other forums on this site. And maybe I missed it, but assumptions seem to be on glassy waters, I think in the real world, if you rely on the range claimed by those manufactures, you'll need a tow.
     
  8. Wavewacker
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    Wavewacker Senior Member

    Gees, what I really meant to say was that choosing a naval engineer type should probably begin with your due diligence in finding those that specialize or at least have completed the type of work you want done.

    After that, I think a personal interview is necessary with any professional. Basically, do you see ey to ey on the subject. If you hire an attorney that really feels that you are guilty and that you need to suffer, after paying his fee, maybe that's not the advocate you really need. When you have to work closely with someone, having a common goal and personality is important, do they or can they see things your way? Since this is a new frontier, maybe there are people out there that want to experiment with options, maybe you can work a deal. Just a thought.
     
  9. daiquiri
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    daiquiri Engineering and Design

    Much more than just a thought, I'd say... ;)
     
  10. Alik
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    Alik Senior Member

    I don't think TS will have much choice - not many NA's would like to involve in such small and such special/weird project. Small project - small money; high expectations and high risk of failure. I used to stay away from such very small craft, also where wrong concept could be already deep in customer's mind.

    So start not from due dillignece, start from checking who is willing to involve :D
     
  11. ViennaYachtworx
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    ViennaYachtworx Junior Member

    Thanks for the numerous answers!

    So we've established that a weight limit of 250kg (total), as recommended by the torqeedo engineers and the right hull form could do the job.

    Yes, I agree, a long and slim displacement craft would be the sensible solution but that is not sellable. The customers wants to plane electric for a (relatively) small buck. Range is not so much a problem as the customer can still resort to displacement mode when he wants range.

    Which brings us back to the main question: How do we find the right naval architect for the job?
     
  12. daiquiri
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    daiquiri Engineering and Design

    By posting a request and evaluating the proposed solutions. ;)
     
  13. apex1

    apex1 Guest

    As Alik already mentioned:

    I fear NOT.

    The requirements are just wrong. That will not attract a skilled professional to take that risk.

    Regards
    Richard
     
  14. Wavewacker
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    Wavewacker Senior Member

    Vienna...You would be surprised at how quickly money changes an opinion.
     

  15. apex1

    apex1 Guest

    Maybe, and then you pay far more for the plan than for several boats?

    Does not sound too attractive.
     
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