Atkins - compared to modern design/materials

Discussion in 'Powerboats' started by Standpipe, Feb 26, 2015.

  1. Easy Rider
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    Easy Rider Senior Member

    If built light out of plywood she'd probably actually cruise at 15mph on OB power but her motion probably wouldn't be very pleasant .. not going to guess about safe.

    Tang's lines look a lot like Handy Billy. We're Billy A and W Hand friends?
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Just about any boat that size, at that speed, (mid-teens mph) is going to have a high angle of trim, unless it is built super-light, and then won't sit on its design waterline anyway. That may not be the end of the world, running nose high might be drier, and with the heavily-veed forward sections still a good cut-water.
     
  3. PAR
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    PAR Yacht Designer/Builder

    I eluded to this in a previous post, most boats need to run on or around their designed weight or they're too far off their lines, even if balance and centers has been kept close to the original. Lets say you have a 22', two ton powerboat with modest, variable deadrise, a typical warped bottom and you've "engineering" it down to 1.5 tons, yet kept it strong and stiff. Well in this trim she'll have more speed potential because of the lighter weight and decreased wetted surface, but also be cause of these two things she likely "dry 'er chines" at a lower top speed, because the lighter hull will rise up and dust off the transom chines at speed. This can be a very dangerous thing and why it's wise to have a pro look over what you have in mind, so the boat doesn't do something nasty at 60 MPH, like swap ends.
     
  4. Easy Rider
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    Easy Rider Senior Member

    Sixty mph in an Atkins design?

    What a thought.
     
  5. Wckoek
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    Wckoek Junior Member

    Atkins have such a wide scope of design, say if one wanted to study their designs, which are the more refined of their characteristic designs?
    Say like their double ended, seabright, or 5 of their best designs available on the list for sale.
     
  6. PAR
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    PAR Yacht Designer/Builder

    This is quite an old thread, but an answer your your questions are simply impossible, given the volume of work of John and his father. I'm the owner of the last design John was commissioned to draw up, so it might be the most refined of the box keel designs, though knowing what I do about it and them, it's not. What it is, was a "safe" way to go for this commission's SOR, which was to a long time patron and friend. He and his friend put many miles under her keel and it was one of his favorites. Billy started the box keel research and developed it up quite a bit, to which John followed, furthering the type. They played with the SeaBrites a fair bit too. John has some designs for plywood (develop surfaces), but Billy didn't as far as I know.

    Unfortunately, all most of these designs don't benefit modern thinking, nor material selections. They tend to be heavy, though comfortable and some surprisingly efficient like my 37' double ender. As a case study, you could select from several types from this father and son team, as to which you might want to do this with, well you'd be the best decision maker in this regard, as we don't know what you're looking for. You might want to contact Pat Atkins, John's widow. I'm pretty sure she's still alive, though I haven't seen her since Mystic in 2011
     
  7. graywolf
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    graywolf Junior Member

    I really like the water cooled machine gun on the cabin top.

    All the metal saving features indicate it was designed during WWII. Wonder where they would get the engines? Oh, designed for the Coast Guard, guess the government would not have a problem requisitioning them.
     
  8. ned L
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    ned L Junior Member

    I also realize this thread is dated, but some of the topic is near and dear to me. The rolled garboard and boxed garboard methods of construction trace their roots back to at least the 1830's (Rolled garboard and boxed garboard being two quite different construction methods to accomplish very similar bottom shapes.)
    The Jersey sea skiffs with rolled or boxed keels were easily pushed, sea kindly and very capable boats.
    -I grew up three blocks from Sea Bright, and for half a dozen years had a 24' Hankins sea skiff in our family (Charlie Hankins was the last builder of rolled and boxed garboard keel sea skiffs.)
     
  9. Dorydude
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    Dorydude New Member

    [​IMG]
    I recently built a "Hope" with modern techniques. The frames were spaced a little to take it out to 30 ft. The bottom was 12mm ply and topsides were double diagonal 4 mm ply. The original design had engine amidships and fuel tank aft, so I swapped them. Put 200 litres of fuel midships and a 90 ETEC outboard in the stern.

    To cut a long story short, the boat worked very well. Top speed was around 23 knots and it cruised at 18 knots.[​IMG]
    [​IMG]
     
    Last edited: Aug 11, 2017
  10. Rurudyne
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    Rurudyne Senior Member

    She is beautiful.
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    Dorydude, how did you manage to sheet the bottom with ply, the lines appear not to be developable ? Do you get a lot of bow lift at speed ? How does she keep on track in following seas, there appears to be not much lateral plane aft ?
     
  12. Dorydude
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    Dorydude New Member

    [​IMG]

    [​IMG]

    I used 2x 6mm ply on the bow sections. From memory it all went down pretty easily.

    Yes, the bow lifts at speed, that's how these hulls work, they rock back onto their flat aft sections. Bow lift is not excessive.

    She tracks ok in following seas. I never took her out in rough weather. These are a sheltered water/ nice day type boat, although they will handle bad weather.

    If you want a heavy weather machine you simply get a deep V hull that is double the weight with 4x the horsepower. The owners of boats like this only seem to go out on nice calm days anyway;-).
     
  13. Mr Efficiency
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    Mr Efficiency Senior Member

    OK, I can see the skeg there to help tracking.
     
  14. Dorydude
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    Dorydude New Member

    Yup. I don't think that was in the plans.
     

  15. Mr Efficiency
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    Mr Efficiency Senior Member

    Likely a wise inclusion.
     
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