Function of design

Discussion in 'Boat Design' started by Salmoneyes, Nov 5, 2018.

  1. Salmoneyes
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    Salmoneyes Junior Member

    I have been working on a custom dinghy build, and have some help from a professional architect but do not want to be annoying with too many questions, so I am interested in spreading that load a little..

    I came across this little Garvey Boat design that has an interesting stern concept. I am just curious what others think of the advantage or disadvantage of moving the transom forward like this. Cackler14.jpg
     
    Last edited: Nov 5, 2018
  2. philSweet
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    philSweet Senior Member

    Protects the motor at the dingy dock and lets you run without a tiller extension. If swamped, can be designed to keep the powerhead above water. Easier to mount/demount the motor in the water. In my case, I lower my dink from the bow, and then have to lift the motor off the storage bracket on the transom and mount it on the dink. You can also do a deep water recovery over the stern if you need to. Boat tows a bit better as well. There are more and more of these showing up now. One last thing, you can build a 9'6" dinghy out of 8' sheets if you are clever about it - without scarfs.
     
  3. Salmoneyes
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    Salmoneyes Junior Member

    In deep water recovery, are we talking pulling an anchor or crab pot situation?
    Tows better, this is important, and curious how and why.... on its own merit without bow shape influences.

    This is exactly the kind of discussion I was hoping for.. Thank You
     
  4. JosephT
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    JosephT Senior Member

    Agree with philSweet, most of the rubber dinghies share the forward transom. I tow one while sailing and it does help them track a bit nicer while under way. The illustration below shows the approach. If you'll be doing any towing at all you'll want two towing eyes on the bow. The length of the tow line will vary depending on speed & conditions. Rule of thumb is to adjust it as needed for your current speed until it pulls smoothly without zig-zagging much. Good luck!

    [​IMG]
     
  5. Salmoneyes
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    Salmoneyes Junior Member

    I just edited, but for those who saw it, I referred to the hull as a "Jon" boat, but it is actually a "Garvey"
     
  6. messabout
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    messabout Senior Member

    That feature used to be called "squat boards". The concept has been around for a long time and it does have some advantages. Among those possible advantages are that they will usually get on a plane more quickly and and with less bow rise. If the squat boards are enclosed there is the advantage of extra buoyancy at the transom where the weight of the motor is. That can be a good feature if the motor is to be manually started. Other advantages as Phil mentioned above, such as making tiller steering a bit more practical in terms of overall boat trim.


    The distinction between Garvey and Jon boat could be the subject of conversation or argument..........The difference, if any, is that Jon boats are usually thought of as aluminum mortar box like boats . The sides of a Jon are pretty much parallel while a Garvey may (or may not) have some curvature in the sides. I do not suppose that it matters much about what we call the boat.
     
  7. Salmoneyes
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    Salmoneyes Junior Member

    Thank you for mentioning the arguable distinctions, as I was afraid after I edited, it could cause some debate ( which now you may have prevented)... It is not relevant to this question, but I am working on both concepts for my application, at which time I may toss it out here for debate....
     
  8. Salmoneyes
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    Salmoneyes Junior Member

    I like those advantages that have been tabled. I should mention, I want side console steering, and electric start so a couple advantages will not apply to this project. I would like to hear more if they exist.

    The tow ability certainly will add a check in the overall advantage column but I have to think it requires the correct bow to see that realized. That could move the check the other way..

    So how about the negatives?
     
  9. DCockey
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    DCockey Senior Member

    Jonboats, aka johnboats, originated in the Ozarks, were paddled and built from wood planks. Traditional jonboats were narrow, shallow and the side planks were typically sprung so that the middle of the boat was wider than the ends. http://mofolkarts.missouri.edu/wp-content/uploads/2017/05/johnboat.pdf 1920 ERA JON BOAT FOUND IN THE WHITE RIVER BY COTTER TROUT DOCK GUIDE http://www.cottertroutdock.com/Michael.htm

    Garveys originated in southern New Jersey and later spread to the Chesapeake. Garveys were built with both flat and v bottoms. Howard Chapelle's American Small Sailing Craft has 14 pages on flat bottom garveys and 3 pages on v-bottom garveys.
     
  10. DCockey
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    DCockey Senior Member

    Less interior space for a given hull length.
    More complex construction.
     
  11. Salmoneyes
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    Salmoneyes Junior Member

    Thank you for that clarification.. I only felt it was important since the designer may very well see it on here and could take offense since he designed it on the "Garvey" hull concept.

    I have spent many many hours hunting and fishing on "Jon Boats" here in Oregon, and I even took mine to Belize, where it went bow down in Gails Point faster than you can blink when a 14 year old kid jumped up to the bow while under way with 2 grown adults.. It was scary fast how quick she went under
     
  12. Salmoneyes
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    Salmoneyes Junior Member

    Good points both.

    I am still researching these and just came across a review of this same boat, and the author claims from wide open to full stop, the approaching stern wave did not enter the boat at all. I am struggling to believe that.
     
  13. Salmoneyes
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    Salmoneyes Junior Member

    Could you help me with this a bit more? I have been looking for hours on line and I have not found a another boat with this type of transom. Is it possible that the term you used is regional one, or perhaps general?
     
  14. DCockey
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    DCockey Senior Member

    I've seen "squat boards" used as the name for horizontal boards added at the stern of Chesapeake Bay work boats to prevent the boats from "squatting". Typically the boards were used when more powerful engines were install in hull designs originally intended for sail or low power engines. I've never seen a notched transom as illustrated in the first post called "squat boards".
     

  15. philSweet
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    philSweet Senior Member

    It tows better because the center of gravity of the towed, empty boat is further forward relative to the drag center. You want the boat to tow with and without the motor. The less change in CG the motor creates, the better. The further forward the painter bridle is attached, the better.

    I extended the sides of the aft boxes down about 1/2 inch below the box bottoms to form little skegs. In a following sea, I lower the motor so it doesn't surf up behind me. My tow rig looks exactly like Joseph's, complete with the idiot cord.
     
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