Inexpensive power boat with NO wake?

Discussion in 'Powerboats' started by sprit, Nov 21, 2013.

  1. daiquiri
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    daiquiri Engineering and Design

    No wake means - no boat. Approaching that condition becomes - a low-wake boat. :p
     
  2. PAR
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    PAR Yacht Designer/Builder

    "No Wake" is defined as a carpet of slightly disturbed water, behind the boat, without breaking waves or crests. Of course, this can be subjective by the ticket issuer, but not difficult to visualize, with some experience. The USCG defines this as no white water in the wake, meaning no breaking water or "horsed" crests. Essentially, it means the slowest possible speed to maintain steerage.

    You can design a boat to have nearly no wake at speed and pretty much barely disturbed water in displacement mode. It's not for the faint of heart designer with FreeShip, but it can and has been done.
     
  3. Mr Efficiency
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    Mr Efficiency Senior Member

    A no-wake boat that is cheap ? How about a tantrum-free Miss Universe look-alike to crew it ? Too easy !!!!!!
     
  4. daiquiri
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    daiquiri Engineering and Design

    PAR, I have frankly never heard of a formal definition of a "no wake" different from its linguistical meaning - zero wake.
    But that issue is imo not so important to make us start a discussion about semantics. Evidently, my "no-wake" is not the same as your "no-wake", but nevertheless we all understand what is Sprit looking for. Which is the important thing here. :)
    Cheers
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    As you note D, it is all in the definition.

    The traditional naval slang/nomenclature of Wake means simply:

    "..The line of water astern of a ship through which she has just passed: the opposite to grain..."

    So, what is grain??:-

    "..An old (XVII century) word for the line of water ahead of a ship along which she will pass: the opposite to wake..."


    And bear in mind, these old navy boys whom sailed the seven seas had been doing this for centuries before anyone started linking 'wake' with props, or 'wash' etc. :p
     
  6. sprit
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    sprit Junior Member

    May I point point out that a single scull rower can do 2000 meters in about 6 minutes (14 mph; 12 knots) with less than one HP, and very little wake from the hull?

    [But the carbon fiber hull probably cost $30,000.]
     
  7. daiquiri
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    daiquiri Engineering and Design

    That's yet another dimension added to the word "wake", separated from any physical characteristics of a wake itself - the body of water left behind the hull, regardless of what it looks like.
    This forum is really a great place for expanding one's general knowledge, isn't it? :)
     
  8. DCockey
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    DCockey Senior Member

    In the US and Canada there are regulatory "no wake" zones. PAR's definition sounds like what the regulations mean as opposed to the literal "no wake" which would imply no boat as Daquiri noted.
     
  9. PAR
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    PAR Yacht Designer/Builder

    There is a meaningless literal definition and the one that will actually get you a ticket, by a harbor patrol officer, which does have a definition. Again, it can be subjective, but it's easy to see in most cases. In fact, in most cases, if you're right of the edge of producing, what they've been trained to understand as a wake, they'll usually tell you just to knock a few hundred RPM off your engine, to maintain the "no wake" speed. If this makes your craft uncontrollable, they might let you go, but more often then not, they know your boat make and model better than you and you'll get the ticket for arguing about something they clearly have a better grasp of.

    There's also another aspect of the law, which is "reasonable effort", which again can be subjective, but if you've shown a reasonable effort to operate within whatever restriction you are contending with, you're usually given the benefit of the doubt. Simply put, if a judge heard evidence about gear ratios, prop dimensions and hydrodynamic issues, particular to your vessel, making it all but imposable to steer your boat at this speed, the case would likely get tossed out, because you made a "reasonable effort" to comply with the statute.
     
  10. Squidly-Diddly
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    Squidly-Diddly Senior Member

    google "box keel, no wake"

    https://www.google.com/search?q=box...s=org.mozilla:en-US:official&client=firefox-a

    Looks like these could be built fairly easily stitch and glue (almost all fairly flat surfaces at near 90' angles).

    Seems to be the hull if you want 'magic' regarding no wake at decent speed.

    I'd heard they only like to work really well at narrow speed range (planing but not too fast), so might be tricky to design.

    I wonder if hull design water flow software can do the 'voodoo' these things are supposed to have.

    My guess is they would also be very good stable hulls at rest, since they aren't all round and slippery rocking back and forth.
     
  11. PAR
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    PAR Yacht Designer/Builder

    I own a 37' Atkins box keel design and indeed it's wake is barely appreciable at less than S/L 1.3. At speeds of 6 MPH or less, it's just a slightly ruffled carpet of water behind the boat. To push this hull form past 1.3, the typical solution (for Atkins and others) was a hook, though a reversed V with a box keel might help a bit. Yes, they're hard to get right without a good frame of reference or lots of testing.
     
  12. michael pierzga
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    michael pierzga Senior Member

  13. Wavewacker
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    Wavewacker Senior Member

    Interesting, although telling a judge here that your boat can't perform without producing a wake you'll likely be told to keep your boat out of that area.

    Always great to hear PAR's take on things, as well as the other pros, I was thinking I could walk through water a produce a wake.

    What about a catamaran with the fish-form hulls like a kayak where the tunnel cancels out the center or inside wake produced?
     

  14. Scheny
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    Scheny Junior Member

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