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Thread: Guidance for a very bad idea....enlarging pram design

  1. #1
    Join Date
    Mar 2019
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    Cape Cod, Massachusetts, USA
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    Default Guidance for a very bad idea....enlarging pram design

    I have happily recovered from the boat burnout that occurred after finishing up a Bolger junebug. I did not think about boats much for weeks. Of course there is no cure for this affliction and the family has begun to ask for a beach/utility/fishing/clamming etc boat. The boat will be for messing about in a bay, with the only real hazard being wakes.

    Hours of searching, and reading dozens of posts about garveys on this site, and some trials of friends boats later, and I have hatched a terrible idea: take an old design for a pram and an enlarge it to the size I want. I fully understand how foolish this could be. However, Iíve built a skiff this way before, the boat will include ample floatation, and increased scantlings are not too hard to figure out. The goal is maximum volume. My kids have outgrown the 12ft x5ft brockway type skiff I built (it was perfect at first).The junebug is waaay too small. I read and reread Thad van Guilders posts on how to build a garvey and fit the tea some to strongback.

    Here is the design. It is literally exactly what I have been looking for since I started building boats 12 years ago. The only issue is it needs to be bigger. Iím thinking of stretching to 14í6 and raising the sheer or just a straight 20% scale up.

    EA080850-9339-4D9F-B77F-5A863FF31FD2.jpg

  2. #2
    Join Date
    Dec 2003
    Location
    Sound Beach, NY
    Posts
    4,618

    Default Re: Guidance for a very bad idea....enlarging pram design

    I would make a model first. I've read that it's okay to expend 10%, and I sail a ketch that is a 10% enlargement of a 36' schooner.
    If you decide to make your changes, try to find a successful design with similar dimensions. If yours is about the same, it probably won't have fatal flaws.
    Good luck, keep us posted.

  3. #3
    Join Date
    Mar 2017
    Location
    Metro West, MA
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    23

  4. #4
    Join Date
    Mar 2019
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    Cape Cod, Massachusetts, USA
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    Default Re: Guidance for a very bad idea....enlarging pram design

    The Mertens boats look very nice but they are designed for much higher horsepower. I am looking to stick to 6-10 hp.

    I just tried a 1/8 scale up, or 12.5%, that brings the overall length to 13'6", 5'5" max beam, and 4' 2" 5/8" waterline beam, which is a good size, and doesn't seem like too much of a stretch.

  5. #5
    Join Date
    Aug 2016
    Location
    Queens, NY
    Posts
    307

    Default Re: Guidance for a very bad idea....enlarging pram design

    Last edited by coelcanth; 07-21-2021 at 08:56 PM.

  6. #6
    Join Date
    Jan 2020
    Location
    chattanooga, tn USA
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    Default Re: Guidance for a very bad idea....enlarging pram design

    I found a skiff design about 12 years ago. It’s in a book by Edwin Monk on small boat designs. A 12’ skiff, slab sided, I wanted to be 16’. So I copied page from book, sent to Karl Stambaugh. He returned cut files so I could build it with 1/8” 5086 Al. Fortunately I got 4’ x20’ sheets because when I measured LOA it was right at 18’. Designers work by keel length. Rows well, handles well, with one or three, 4 people in it and two rowers. Two rowers no passenger in stern seat, its bow heavy, makes a mess of any skill set. And I don’t go out in any kind of breeze unless I really want a workout. Right now the boat’s in Eastern N C where wind waits for someone to try rowing. So I’m plotting a daggerboard trunk and board and sail rig right out of American Small Sailing Craft. And I’m wondering should I take the Simon Watt Norwegian pram design and stretch it from 12’ to 16’ or so. That would be fun to do going by how one builds them. Even found a copy of inshore craft of Norway to taunt the fantasy. So be careful what you wish for...

  7. #7
    Join Date
    May 2016
    Location
    Pacific drifting
    Posts
    537

    Default Re: Guidance for a very bad idea....enlarging pram design

    Jim Michalak`s IMB is compact but can carry a lot of weight.

    Easy build , and you could easily omit the cabin.

    Small outboard would be ok.

    https://www.google.com/url?sa=i&url=...AAAAAdAAAAABAP

    imb4.jpg



    http://theoarcruising.blogspot.com/2...her-style.html

  8. #8
    Join Date
    Jan 2008
    Location
    Bow, Wa
    Posts
    431

    Default Re: Guidance for a very bad idea....enlarging pram design

    Paul Gartside has the 'eye'.

    What about this? https://store.gartsideboats.com/coll...ram-design-222

  9. #9
    Join Date
    Mar 2017
    Location
    Loon Lake, Washington
    Posts
    258

    Default Re: Guidance for a very bad idea....enlarging pram design

    My favorite "Garvey" of about that size is Joe Dobblers -



    And plans are only 20 bucks.

    Is it really a Garvey without the curved bow? Or is it just a fancy John boat?
    If it was me building it, I'd take the time to make a proper Gravey bow, just for the fun of it.
    Anyway, this is primarily a sailboat but I'm sure it would work fine with a low power motor.



    https://duckworks.com/presto-16-plans/

  10. #10
    Join Date
    Mar 2017
    Location
    Loon Lake, Washington
    Posts
    258

    Default Re: Guidance for a very bad idea....enlarging pram design

    Oh, and by the by, I see no difficulties at all in stretching the boat at top, and it's fun to build a boat you designed yourself!

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