Small Steel Workboat Design

Discussion in 'Boat Design' started by Ozparker72, Mar 24, 2014.

  1. rasorinc
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    rasorinc Senior Member

    Glen-L often details out an outboard option. look up client build pictures of this and other tugs. You can design your own cabin to suit your needs. more HP will give it to you as well as some pitch changes to the bottom frames and a redraw of the transom for an outboard. Glen-L has a great forum also and you can find someone who has built that model. many make lots of changes
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    What gauge did you have in mind to be using ?
     
  3. waikikin
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    waikikin Senior Member

    A small steel boat is always going to be heavy, maybe 7-900kg for a 18-20 footer with some stuff aboard, An outboard is a terrific option, steering gearbox & engine in the one neat unit, portable tank & hose ... off you go!
    Anything under 2.5mm really doesn't belong in a saltwater environment, as much as coatings can be good scratches happen, your weldout will be easier with thicker plate, go 3mm, nice pipe sponson/gunnel & accept that small & steel will be "heavy".
    Speed will be lower............. with a heavier boat, your going to be in displacement mode & 5-6 knots.

    For translation, just copy & paste the text into a "google translator", the phrasiology will be a bit different but understandable, that article is more about young blokes having some fun than design & building though

    Jeff.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    Wanting to cruise at 7 knots makes this a little difficult, a 16' heavyweight boat, regardless of hull form, will not be happy at that speed. If you want to run faster, say 15 knot cruise with a planing hull ( possible with a beamy, flattish bottom) you will need 80 or 90 hp on the back.
     
  5. Ozparker72
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    Ozparker72 Junior Member

    Jeff, I agree with you that anything less than 2.5 in salt water is not a good idea. I often work on larger steel boats 60ft +, I have re-plated a few, hence my desire to avoid thin plate.

    So thats one reason I want to build from 3mm, the other is, that its much quicker to weld and easier to fair.

    Mr Efficiency, i think Im going to have to accept that the boat i need, and can afford to build will have to have a max speed of 5-6 knots, thats ok.

    I like displacement hulls, I find them more fuel efficient (maybe Im wrong?) and Im rarely in a hurry. I feel safer in a boat thats riding "in" the water rather than one thats riding "on".

    Having said that, my knowledge and experience is very limited, just tugboats and planing dinghies.
     
  6. Ozparker72
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    Ozparker72 Junior Member

    Rasorinc, thanks for the tips.
    Sweet 16, seems to be the only realistic candidate so-far.
    I dont really want or need a cabin, which would make for a quicker build.
    I assume I would then have more weight carrying capacity?
     
  7. rasorinc
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    rasorinc Senior Member

    You might go to the Glen-L site and look at their Pacific Dory's. All outboards, very easy builds and easy to make changes. Work well in heavy water and can carry huge weight. Stan They have them from 13' to 26' + 10%
     
  8. Milan
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    Milan Senior Member

  9. Ozparker72
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    Ozparker72 Junior Member

    Milan, thanks that's very helpful
    http://www.bootdesign.eu/home/17 looks really interesting
    The "Billy 500" looks like it might fit the bill, just need to translate page now
     
  10. Ozparker72
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    Ozparker72 Junior Member

    I have decided to build my own design in steel,
    After all, what could possibly go wrong:D

    I have done the drawings, and worked out the frames,
    It is 15ft 8" length
    6ft 10" beam
    It's a hard chine boat with 3 planks/strips
    Each side
    Sharp bow, and I've put in a rocker in the bottom.

    As I'm building from 3mm plate, I'm going to use minimum framing,
    Heavily relying for strength on a semi monococ design using a foredeck and side decks, also welded flotation tanks fore&aft will add rigidity.
    I will also be adding an out board well , again I can use this to gain structural strength. A water tight floor will be welded in to add safety, and will be filled
    with foam. And a combing to top it off.

    I've drawn up the panels, and calculated the weight at 300 kgs, dry weight.



    on a hard chine
     
  11. Ozparker72
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    Ozparker72 Junior Member

    Oops, forgot to add weight of outboard well and combings
    340 kgs dry wieght
     
  12. peter radclyffe
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    peter radclyffe Senior Member

    a heavy steel workboat, no kidding, :D
    its just what you need
    i guess your N A is not dutch
     
  13. Ozparker72
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    Ozparker72 Junior Member

    Your right there, he's English.
    His comments were that, "years ago he used to build small Line Boats (25ft), the feedback he received from clients was that they were Unstable, so he had to greatly increase Beam to correct this."
     
  14. tdem
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    tdem Senior Member

    1 person likes this.

  15. Ozparker72
    Joined: Mar 2014
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    Ozparker72 Junior Member

    Thomas, thanks so much for the links
    What a beautiful boat, I love it!

    This is exactly what ive been looking for!
    5.6 meters is a bit big for me, however if I can build it to 4.8 meters then I think that this is perfect for me.


    Would a 15hp outboard be enough power for propulsion?
     
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