Making a Punt

Discussion in 'Boat Design' started by pdmclean, Nov 11, 2014.

  1. pdmclean
    Joined: Nov 2014
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    Location: Hobart, Tasmania

    pdmclean Junior Member

    Hi,

    I'm thinking of making a punt similar to this one featured at

    http://www.christinedemerchant.com/free-punt-plans.html

    [​IMG]

    [​IMG]

    I have some pieces of 9mm Plywood and lots of 50mm by 150mm Hardwood. I have minimal tools (Hand saw and Electric Drill, I could buy a circular saw) and basic woodworking skills, but no boatbuilding skills. I would screw and glue it together, caulk it with Sikaflex and seal it with paint or polyurethane.


    This is the plan I came up with. I used Sketchup and couldn't scale it properly. The dimensions should be 3.8m by 1.2m by 0.3m.

    [​IMG]

    It could be poled or rowed/paddled. With some modification it could take a sail or motor. I have 2 kids aged 4 and 7. We live near the Derwent estuary and we (currently) wouldn't want to move this boat very often with our car.

    I would like to know how this would handle. How easy it would be to build and seal.
     

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  2. messabout
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    Location: Lakeland Fl USA

    messabout Senior Member

    The punt is serviceable little boat if used within its' capabilities. True it can be rowed, poled, sculled. or propelled by a small outboard. It is simple and economical to build. However the descriptions you have shown are very dated. We would not build the punt quite like that these days.

    Hard angular corners on any external surface are not acceptable for a boat to move smartly. The modern way to build the small boat is with plywood and the plywood is bent into gentle curves rather than being pieced together at hard corners. A knowledgeable builder could assemble a boat like that in one day, not counting finish work like paint. Such a boat could use the stitch and glue method to great advantage.

    Please explore a bit longer and find a set of boat plans that are not so seriously dated as the one that you have shown. That plan must be 50 or more years old.

    Do yourself one huge favor by buying a set of plans from an acknowledged small boat designer. I swear to you that you will save money and have a far better boat, a lighter weight boat, a more durable boat, a more pleasurable boat, by getting a complete set of plans from a professional designer and definitely not a magazine or other source where you have no idea of the competence of the one who drew the plans. I can tell you, with confidence, that the one who drew these plans was not a knowledgeable boat person.

    That boat would float, it would move through the water with some effort. On the other hand a more sophisticated, not to say complicated, design would work far more easily,.
     
  3. NoEyeDeer
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    NoEyeDeer Senior Member

    Do NOT think of taking such a boat out on the Derwent estuary either. Not unless you are seriously trying to reduce the size of your family. Punts are flat water boats only.

    But yes, Messabout is basically right. The old plans aren't that great. Your sketch isn't very good either. At least the old plans have the sides in one continuous length, which is a very good thing.
     
  4. lewisboats
    Joined: Oct 2002
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    lewisboats Obsessed Member

    You've cut out too much buoyancy in the ends... you will need to sit directly in the middle if you don't want to plow whichever end you are sitting in into the water.
     
  5. pdmclean
    Joined: Nov 2014
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    Location: Hobart, Tasmania

    pdmclean Junior Member

    Thanks for the advice. You've all added important criticism.

    I can see that the angles aren't very contemporary, but I wonder how much drag they would add. Not all boats have smooth curves http://www.boatdesign.net/forums/boat-design/english-punt-twist-28645.html. I am aware of my own limitations in terms of materials (I have a small amount (1x1.2 and 1.4x1.2) of thick (9mm) plywood) and my woodwork skills are rudimentary. I might make a slicker boat in the future.

    Any advice for someone who's scare of curves?


    Regarding the sides not being continuous - I'm relying on the centre member to give it structure and rigidity - the sides are just there to keep the water out!

    Regarding its seaworthiness - I wouldn't take it out very far or in rough weather.

    Regarding it's bouyancy/balance - I imagine two kids in there with me poling from the back. Can I add bouyancy by using lighter materials or changing the angles?
     
    Last edited: Nov 12, 2014
  6. The Q
    Joined: Feb 2014
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    Location: Norfolk, UK

    The Q Senior Member

    If you wish to sail a punt have a look at, The Norfolk(UK) Punts
    http://www.norfolkpunt.org/
    probably a bit livelier than your thinking of!!
     
  7. NoEyeDeer
    Joined: Jun 2010
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    NoEyeDeer Senior Member

    I'll tell you what they do add: structural weakness and built-in failure points. How is this an advantage? Plus you still have to join the bits together anyway, which is work.

    OTOH, if you use a continuous curve you may have to cut the curve, but you don't have to cut as many joins, and you get a stronger boat.


    You need more plywood. Yes. You do. Go and get it.


    Stop being scared. Curves are good, on boats as well as women. Being scared of curves is no fun at all.


    WTF? What centre member? Why do you need a centre member in a punt? Do it right and you'll have a lot more usable internal space.


    Seriously, do not take it out on the Derwent estuary. Just don't. Sooner or later that will dump you in the poo.


    Yes.
     
  8. pdmclean
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    pdmclean Junior Member

    @NoEyeDeer : Great! That's the sort of feedback I love.
     
  9. JRD
    Joined: May 2010
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    JRD Senior Member

    Lots of good reading and boat building info in here. Including curves, so download and have a read.....

    http://www.westsystem.com/ss/assets/HowTo-Publications/GougeonBook 061205.pdf

    If you are looking to find a cheap and cheerful design and build, pick up a copy of your Australian Wooden Boat Builder Magazine. Some weird and wonderful build ideas at times, but most are based on being easy to build at home.
     
  10. NoEyeDeer
    Joined: Jun 2010
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    NoEyeDeer Senior Member

    pdmclean, I have a suggestion. Decide what you want the boat to do, and how much you are prepared to spend on it. Once you have those things figured out, people will be able to give you better advice.

    My impression so far is that something like a SOF Whitehall may suit you better, in terms of results, as it would be cheap, easy to construct, and more versatile than a punt.
     
  11. Dave Gentry
    Joined: May 2010
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    Dave Gentry Junior Member

    Great advice - especially about the SOF Whitehall.

    If you want a punt, there's no need to reinvent the wheel. Inexpensive plans for an extremely simple to build plywood punt can be found here:
    http://www.duckworksbbs.com/plans/jim/polepunt/index.htm

    Good luck!
     
  12. NoEyeDeer
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    NoEyeDeer Senior Member

    The Duckworks punt would be a very good one, if a punt is what's wanted.

    My concern is that pdmclean seems to have little or no boating experience, and the Derwent estuary is a big estuary that can really cut up rough without a lot of warning. It's not what I'd think of as punt territory, and beginners always tend to overconfidence. I've spent enough time in punts (mainly aluminium outboard versions) with varying loads under varying conditions, and they can be very nasty things in the wrong circumstances.
     
  13. pdmclean
    Joined: Nov 2014
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    pdmclean Junior Member

    You're right - I have no experience. My resources are (at this stage) - fixed some leftover bits of plywood and mdf.

    But I've taken heed of your comments about the limitations of a punt - I'm saving the good plywood for the future and I've started building a canoe/kayak using the MDF.

    I put a slight curve in the ends of the 0.3mx2.4m sides. Then I cable tied the ends together. Next I'll decide on a width (Will I fit?) and trace out a bottom - I'm not sure whether to have a flat bottom or to make a slight v shape. I'll need to put a seam across the middle as I don't have a long enough piece of MDF. What do you think?

    Is there an ultracheap and easy to use alternative to epoxy? Gap filler(No More Gaps or noname alternative)? Liquid Nails (Is this polyurethane)? Expanding Foam? My son wants to paint it - so this should go some way to seal it.

    The purpose is to paddle in the calm, shallows at the the beach. In any case, if it keeps out the water for half an hour then it has served it purpose. If it lasts a few outings it has served its purpose three times over!
     
  14. NoEyeDeer
    Joined: Jun 2010
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    NoEyeDeer Senior Member

    MDF will start turning into soggy Weetbix as soon as it smells water. It'll be screwed in ten minutes (literally) if you actually try to use it in water. Don't even bother. If you want something that floats, use material that won't fall apart when it gets wet.

    You said you have "lots of" Tassie oak. Find a way to rip it to useful sizes for stringers.* Build skin on frame.

    *If you don't have tools for ripping, track down the nearest Men's Shed and pay their annual subscription (usually about a dollar a week) if they have a decent workshop (often do).

    ETA: Oh and the amount of plywood you already have is about right for the frames for an SOF boat too. 9mm would be adequate for thickness, although they often use 12mm. If it's hardwood ply though, it'll be heaps strong enough at 9mm.
     

  15. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    What kind of ballast would those "punts" carry?? Human's only? Bert
     
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