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Thread: simple working boat design

  1. #1
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    Default simple working boat design

    Hi Forum, I am hoping that you can help.

    I am seeking plans for a sail boat which will be used to haul cargo. It needs to be very simple to build, utilise a simple rig and be capable of hauling 750kg cargo on 25 mile cross sea passages. Of course this means that it should be decked and include either a long shoal draft steel keel or some sort of bulb - centre plate arrangement. IT does not need to offer any accommodation or cabin.

    I am of course very willing to amend an existing design to suit my purposes - but I wish to start out as close as possible to my needs. It doesn't need to look pretty and I'd prefer a simple design with limited chines.


    Basically I need a CLC Skerry 15 which has been doubled in size to 30ft, fully decked and includes a steel keel arrangement.

    Are there any existing plans out there which meet this brief?

  2. #2
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    Default Re: simple working boat design

    You might find a hull to suit but you will still need a naval architect to make construction plans, engineer the systems, do stability calculations, and ensure compliance regulations. Might as well commission the NA to work out the hull. You can't just scale up a light hull into a hefty cargo carrier.

    Twenty five miles is a long way to go without shelter from the weather and without a head. You'll want some sort of pilot house to provide for all that.

    Cargo handling and secure stowage have their own constraints. Sounds like you anticipate regular and repeated trips. Hope you have work both ways or it will be hard to make this pay.

    Something like this but not yet yachterized might be an alternative.


  3. #3
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    Default Re: simple working boat design

    Hi, Thanks for your response - just to note the payload won't exceed 750kgs - so not huge.

    I appreciate the difficultly scaling an existing design hence hoping there is something that can be used off-the-shelf.

    Thanks for your input though, useful.

    Should also explain that this is not a commercial endeavour!

  4. #4
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    Default

    Will this cargo sit low and contribute to ballast, is it stable in the boat, will the return trip be without the cargo? What exactly are you planning and what water will you be crossing?

  5. #5
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    Default Re: simple working boat design

    The cargo will be stable and yes will sit quite low. The routes will vary between coastal hops and cross channel. The boat will be used for personal purposes with varied cargo - stone, coal, booze, anchors, cement, grain, fish etc. There will certainly be trips without cargo -although rocks or water can always be added if required.

  6. #6
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    Default Re: simple working boat design

    If you don't mind a US designer, take a look at Atkin. [http://www.atkinboatplans.com] In the thirty foot range there's a clutch of auxilary sail boats that look suitable for plywood or even steel. Some truely flat bottoms if you contemplate a mud berth and some shoal draft like pretty little schooner Capt. Jim Young. With any of these, I'd make the cargo hold divided in half by the centerboard trunk.

    Capt Jim Young might work if you made a much smaller cockpit, sitting headroom accomodation to main mast, cargo between the masts, and parts/rope locker in forepeak. A loosefooted foresail and the right gooseneck or even pedastle would allow for use of the boom to peak up and become a gin-pole crane.

    The engine moved aft a few of inches and put on center could be angled such that the prop is off-set to port. Engineered correctly that angle means that the turning thrust to starboard from the prop being off center is cancelled by the turning thrust to port from the angle off centerline. Cover the engine with a thermal and sound insulated box, add a couple of drop leaves, and you have your saloon table.



    Atkin has not engineered for plywood all hard chine boats but I see no reason why it would be terribly expensive for him to do that, as well as the other work modifications require.
    Last edited by Ian McColgin; 02-03-2021 at 12:32 PM.

  7. #7
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    Default Re: simple working boat design

    Yopu might taka look at this boat from Tad Roberts, along with several related boats. some smaller, some larger:
    http://tadroberts.ca/services/new-design/sail/tilikum32

    tilikum32-arrangement-S.jpg
    Alex

    A man in an open shirt, sat gazing out to sea; A young man, a hale man, and I wished that I were he and that the things that I loved were as they used to be
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  8. #8
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    Default Re: simple working boat design

    Wanzap1,

    You wouldn't be thinking about a spot of smuggling, now would you?

    Dwedais "Gwirion", nid "Twp"

  9. #9
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    Default Re: simple working boat design

    You might look at old fishing designs. They'll hold the weight and take some weather.

  10. #10
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    Default Re: simple working boat design

    Most of the boats billed as sailing cargo boats are a lot bigger than what you have in mind. I would look around for a small sailing fishing boat design rather than something billed for cargo. It sounds like any number of traditional open boats intended for a large load of fish would work fine. Glen-L has a couple of simple 26-27' power or sail dories that would do the job as well as a 24' power cargo design and other work boats that could be adapted to sail.

    https://www.boatdesigns.com/26-Ultra.../products/894/
    https://www.boatdesigns.com/27-Jean-.../products/830/
    https://www.boatdesigns.com/24-Noyo-.../products/540/
    *******
    Matthew Long
    Bolger fan (Brick, Yellow Leaf, June Bug, Tortoise and half a Teal)
    Dreaming of a small cruiser from Atkin, Bolger, Buehler or Parker
    www.cluttonfred.info (I also like homebuilt airplanes!)

  11. #11

    Default Re: simple working boat design

    due to brexit ,some may be tempted to go from france to cork, then n ireland then scotland

  12. #12
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    Default Re: simple working boat design

    You might also check in with John Welsford down in New Zealand, some of his boats like Sherpa carry a large load in a small boat, and a conceptual (not literal) scaling up of that design might well do the job. He has also been involved in a project for power fishing canoes for islanders and might have some designs already cooked up for small working sail craft. See http://www.jwboatdesigns.co.nz/index.html.
    *******
    Matthew Long
    Bolger fan (Brick, Yellow Leaf, June Bug, Tortoise and half a Teal)
    Dreaming of a small cruiser from Atkin, Bolger, Buehler or Parker
    www.cluttonfred.info (I also like homebuilt airplanes!)

  13. #13
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    Default Re: simple working boat design

    Sounds sorta like a block island cowhorn or a mackinaw boat might fit the bill.

  14. #14
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    Default Re: simple working boat design

    You should look at some traditional designs:

    In Harry Sucher's Simplified Boatbuilding - The Flat-Bottom Boat: a 36' scow sloop (Plates 8 and 9) and a 29' scow schooner (Plates 10 and 11).
    In Harry Sucher's Simplified Boatbuilding - The V-Bottom Boat: a 33' terrapin schooner (50 and 51) and a 32' Chesapeake Bay skipjack (Plate 91).
    In Howard Chapelle's American Small Sailing Craft: a 35' Chesapeake Bay skipjack (Figure 116) and a 29' Texas scow sloop (Figure 121).

    The descriptions of these boats give offsets, scantlings, and sail plan dimensions but don't have a lot of construction details. The figures in the Chappelle book are so small as to be almost unreadable, but larger versions are probably available from the Smithsonian ship plans collection. All these designs are for carvel planking, but the shapes are simple enough to be converted to glue-and-screw plywood.

    With the scow designs you'll probably want to keep an eye on the weather for open-sea passages.

    If you can't get access to these books and are interested in the designs, send me a private message and I'll email some scans.
    I will beg you for advice, your reply will be concise, and I will listen very nicely and then go out and do exactly what I want! (Apologies to Lerner and Lowe.)

  15. #15
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    Default Re: simple working boat design

    Quote Originally Posted by Pelirrojo View Post
    Sounds sorta like a block island cowhorn or a mackinaw boat might fit the bill.
    My "western lakes mackinaw" per chapelle currently has 1600# of ballast and could easily take a couple hundred more, but it's got some fiddling aspects to the build: Planks in the bow down low have 70 degrees of twist in the first 7' of the boat. It's double-ended so not much room in the cockpit. In the original hands they were known to take hellish weather, but we are not those original hands. If I was to build it again for lightering cargo or cruising, and didn't care whether it looked true to period, I would seriously consider channeling the Aussies and give it a raised deck, the severe sheer would lend itself well. It would be huge inside, very safe, etc. But I think for your stated purpose, buy used fiberglass cheap to keep it from going in a landfill, gut it and go.

    Ken

  16. #16
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    Default Re: simple working boat design

    Quote Originally Posted by kbowen View Post
    But I think for your stated purpose, buy used fiberglass cheap to keep it from going in a landfill, gut it and go.

    Ken
    I was thinking the same myself. I would think most 30’ cruising boats of at least moderate displacement wouldn’t have a problem with 750 kilos. Removing cruising stores, the water tank and some accommodation would get you that..

    There’s a bunch of heavily built boats from the 70’s of more or less traditional hull form that are rough around the edges and that can be picked up for next to nothing. I can think of a couple at my boatyard. I love the idea of boats destined for the dump being put to good use.

  17. #17
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    Default Re: simple working boat design

    Quote Originally Posted by wanzap1 View Post
    Hi, Thanks for your response - just to note the payload won't exceed 750kgs - so not huge.

    I appreciate the difficultly scaling an existing design hence hoping there is something that can be used off-the-shelf.
    There is an inherent maths/physics problem in simply scaling an existing design. If you double all the linear dimensions (length, beam, height of mast, etc.) the the areas get 4 times as big and the volumes get 8 times as big.

    So if your boat is twice as long, twice as wide, twice as deep as the original, and the sail is the same shape as the original, it will have 4 times as much sail area.

    However, if you make the boat twice as long, are you going to make every piece of timber not only twice as wide but also twice as thick? If so, every piece of timber will be 8 times as heavy as the original. If not, then you will have a different ratio of strength to stresses.

    So do you want a boat that looks like one half the size, but handles completely differently?

    750 Kg is equivalent to 10 small adults. That is not a trivial cargo, and it will matter where and how it is stowed, and the boat will handle differently on the return voyage if it is empty.

    Your best bet would probably be to look at traditional working boats from your region: small fishing boats and the like. Traditional boats evolved to meet the particular challenges of local sea and weather conditions.

    For the simplest but most versatile working rig, consider something like a standing lug yawl. No boom to obstruct the working area, low centre of effort to reduce heeling, plenty of power, and easy to trim and balance.

  18. #18
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    Default Re: simple working boat design

    This is a design by Reuel Parker. It's probably more boat than you need but I'm sure if you want he can design something for you, He's quite reasonable




    Last edited by Rigadog; 02-06-2021 at 11:23 AM.
    If he ever drinks the brew of 10 tanna leaves, he will become a monster the likes of which the world has never seen



  19. #19
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    Default Re: simple working boat design

    These could be made into a cargo carrier

    Last edited by Rigadog; 02-06-2021 at 11:25 AM.
    If he ever drinks the brew of 10 tanna leaves, he will become a monster the likes of which the world has never seen



  20. #20

    Default Re: simple working boat design

    For a no-frills design, how about Spira's big Labrador Dory? All the reasons that are usually given against using big Banks dories for sailing yachts, might make for a good work-boat that can haul cargo. From the pictures on his website, some designing might be necessary to get the right rig and centerboard/daggerboard/fixed-keel arrangement for your purposes. Last time I looked, he also had a lot of pictures showing the construction of the next model down - the Alaskan, which is built the same way. I would also look at Daniel Noyes' big replica dory (Centennial II) on this forum.

  21. #21
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    Default Re: simple working boat design

    Exactly what 750 KG of cargo are you planning to move across what 25 nm of water.....how exposed is the passage, what are to main weather conditions...say 80% or thereabouts?

  22. #22
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    Default Re: simple working boat design

    I was going to recommend a look through Ruel Parkers catalogue too.

    25 miles, sounds like Carlingford Lough maybe? There's gotta be easier ways of moving vaccines! �� That'd be not quite open ocean, Ruels scows might do it.

    for our US brethren, 1 cubic meter of water is 1000kgs, so 750kg is not much.
    It's all fun and games until Darth Vader comes.

  23. #23
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    Default Re: simple working boat design

    You could do worse than look for plans for, or an actual, sailing fishing boat, from pre 1939. They were designed to carry cargoes of fish and still be fast and sail well.

    Also, harbour masters view them favourably and rarely are they checked by customs, my experience anyway.

    Plenty of Manx Nobbies, Loch Fyne types and Galway Hookers around.

  24. #24
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    Default Re: simple working boat design

    A big catboat is about the simplest way to carry a lot of weight though by no means a small project. Ted Brewer's 22' hard-chine Cape Cod Cat has a 10' beam and almost 3 tons displacement propelled by one big 374 sq ft sail with lots of reefs and a modest inboard engine. A version with the cabin cut back to a small cuddy for just a head and storage would make a solid workboat to suit this mission.

    I'd eliminate the inboard and go with an outboard on an offset bracket to free up working space, extend the self-draining sole the full length of the boat, and add a couple of cargo hatches in that watertight deck. When not carrying cargo, you could add a lot of bench seats along the sides and have a fantastic day boat for large groups or add a boom tent for a spacious camp cruiser. A couple of flexible water bladders, well-secured, filled with seawater from a big manual pump could help with ballast when running empty, but a good trader never runs empty, just finds a cargo going the other way. ;-)

    https://www.tedbrewer.com/sail_wood/capecodcat.htm

    Cape-Cod-Cat-anchored.gif
    Last edited by cluttonfred; 02-09-2021 at 08:46 AM.
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    Matthew Long
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    www.cluttonfred.info (I also like homebuilt airplanes!)

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