New build-Freighter canoe

Discussion in 'Wooden Boat Building and Restoration' started by Lost Caddo, Apr 11, 2016.

  1. Lost Caddo
    Joined: Apr 2016
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    Location: Louisiana

    Lost Caddo Junior Member

    I'm building a freighter canoe with the following dimensions (my first build)

    LENGTH-20ft.
    TRANSOM BEAM-43"
    BEAM-53"
    DEPTH AFT-20"
    DEPTH FORWARD-32"

    I'm ready to fiberglass the outside but not sure how many layers to use. Right now I'm thinking 10oz and putting one 50" wide piece down the middle, and then laying a piece from each side to overlap on the bottom. That way the very bottom will have 3 layers, some of the sides will have two layers, and at the top of sides only one layer.
    I plan to finish the boat clear and want to see the Cedar that I have spent so much time on. The canoe will have an outboard and be trailered so weight isn't an issue unless it gets so heavy it cuts down on what I can carry with me in the boat.
    Strength is what I am looking for. I want to carry lot's of gear a long way on river trips.
    I plan on installing a 51 gallon fuel tank. I hesitate to mention that because I'm sure it sounds ridiculous. As I said, I plan on carrying a lot of weight a long way.

    You Tube has brought me along very well on the build and shows technique for fiber-glassing, but I haven't found anything specific on how many layers to use.
    Any guidance will be appreciated.
     
  2. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    What sort of freight are you planning on carrying, and in what conditions?
    Is it the sort of cargo that might damage the hull when being loaded?
    Do you want to be able to concentrate the weight, or spread it out?

    I should think you would want to do a pretty careful stress analysis.
    The gunnels and topsides in an open canoe are pretty critical to the strength.
    You have to be prepared for big waves from passing ships. Hogging etc.

    The Hudson Bay trade canoes were very light, but were well designed and carefully loaded.
    The Micmac sea canoe had a hump in the middle to make it stronger in a big sea.
     
  3. DCockey
    Joined: Oct 2009
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    Location: Midcoast Maine

    DCockey Senior Member

    What is the construction?
     
  4. Lost Caddo
    Joined: Apr 2016
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    Location: Louisiana

    Lost Caddo Junior Member

    No freight. No cargo.
    The weight I am talking about is primarily fuel. My goal is 450 miles between fuel stops. The fuel tank I chose is 51 gals. and the dimensions (long and skinny) were chosen to distribute the weight. There will also be a 6 gallon reserve tank, some light camping gear and food/water for a couple days at a time.
    I agree the Hudson Bay was a great design but they are a little hard to come by, especially in Louisiana. I purchased a design from one of the members of this forum and I like it better each time I look at it.
    As far as loading it carefully, even my wife says I'm pretty careful when I do stupid stuff.
    I have attached pictures of my build.
     

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  5. Lost Caddo
    Joined: Apr 2016
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    Location: Louisiana

    Lost Caddo Junior Member

    DCockey,
    Sorry I didn't include the construction info. I can see that it would be hard to make a helpful recommendation without that information.
    Strip built Western Red Cedar 1/2" thick x 3/4" wide.
     
  6. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    Wow. Beautiful boat. Sounds like a fun trip. You shouldn't need too much more with 1/2" of cedar, but I will leave it to the experts. Besides the 400 pounds of fuel what will the rest of boat and gear and food and water and crew weight add up to? Also, why not go with solar and batteries, and maybe a generator and fuel for cloudy days? What sort of average speed are your shooting for?
     
  7. hoytedow
    Joined: Sep 2009
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    Location: Control Group

    hoytedow Carbon Based Life Form

    Welcome, Lost Caddo.

    That is a beautiful canoe.

    If you want good range, don't build a solar/battery powered boat. A solar panel would be useful to keep a spare battery charged in case the one for your electrical system takes a dump, but otherwise there is no good reason to carry all the extra weight instead of good old fossil fuel.
     
    Last edited: Apr 13, 2016
  8. Lost Caddo
    Joined: Apr 2016
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    Location: Louisiana

    Lost Caddo Junior Member

    Crew 420lbs
    Fuel 400lbs
    Motor 175lbs
    Food/water 100lbs
    Camping 100lbs
    Electronics 50lbs
    Rigging 50lbs
    Safety/ 1st Aid 25lbs

    There won't always be 400lbs of fuel.
    I plan on making several tests for stability before the first big trip.
    If I need to trim weight, I can. If I have capacity for more, I would probably add a 2mtr ham radio and a couple of bean bags.
    Goal is 15mph average, 15 hour days, over a week or so.
     
  9. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    Say 1700 pounds including hull and 2 passengers, on average.

    D/L ratio comfortably under 100
    Speed/Length ratio ~ 3
    Resistance to Displacement ratio ~ 0.1
    Power requirement at 15mph and 68% shaft and prop efficiency = 10 hp
    Fuel Consumption = 5 pounds per hour ? best case ?
    15 mph x 400 pounds / 5 pounds per hour = 1200 miles ???

    I think you might be able to get better fuel economy than you might think.
    I'm not an expert on such things, but you might also get by with a 20hp four stroke.

    If I'm right, it might only be 120 pound motor and say 200 pounds of fuel, when full, for a 600 mile range, best case.
    It looks like a pretty good setup for fuel economy at that speed. Interesting to see how it works out.
    I agree for 15mph solar is not the way to go.
     
  10. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    We built several of these 30 foot canoes in the UK. With 13 people and minimal supplies it went 7 mph with a 4HP outboard. If you keep at or below hull speed , the economy is huge. We burned about .35 gal/hr. which is about 20mpg. With your waterline length, economy speed will be about 6.5mph
     

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  11. Lost Caddo
    Joined: Apr 2016
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    Location: Louisiana

    Lost Caddo Junior Member

    I was using .6lb of fuel per horsepower per hour at WOT for my calculations.
    Don't know if that's right, it's what I was given by someone who had more
    knowledge than I. And I try to use "worst case".
    Using a Yamaha 4-stroke 25HP since I wanted one for another project anyway.
    Most of the trip can be done with a light fuel load as it will be available daily.
    There is only one leg of the trip that requires carrying enough fuel for a distance of 440 miles.

    Edited. I originally typed .1lb of fuel per horsepower but meant .6
     
    Last edited: Apr 11, 2016
  12. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    LC the 0.6 number is probably a safe assumption. Engines are rated in terms of Brake Specific Fuel Consumption (BSFC). Four stroke engines of modern design use 0.45 to 0.50 pounds of gasoline per horsepower per hour. Gasoline has an average specific gravity of 0.7. That is about 6 pounds per gallon give or take a little. Your 51 gallon tank, will then hold roughly 306 pounds of fuel, a tad more than 600 horsepower hours then.

    Before you set off up the Mississippi toward Paducah and points north, You will be obliged to do some testing for fuel consumption, which I am sure that you will do. Your plans sound like a high adventure. I have long wanted to go over to Mobile, put into the Black Warrior river, and head for the Tenn-Tom waterways.......

    We have danced around the original question about sheathing. I'd think maybe two layers of 10 ounce glass/epoxy on the outside and one on the inside. Some of the other guys may suggest differently.
     
  13. Jamie Kennedy
    Joined: Jun 2015
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    Location: Saint John New Brunswick

    Jamie Kennedy Senior Member

    The 0.6 sounds more realistic for a smaller outboard like the 25 horsepower 4 stroke, but you should be pretty much in the sweet spot at 15 mph. Depending on how well the 1/2" cedar went together I think anything more than the first layer of 10oz is insurance for your investment, but probably worth doing. Enjoy your travels.

    A Gonzo said you could have gone slower and skinnier for some real economy.
    Solar electric would be nice and quiet. :)
     
  14. philSweet
    Joined: May 2008
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    Location: Beaufort, SC and H'ville, NC

    philSweet Senior Member

    For a 25 hp and 15 knots, I'd go with 20oz skin of the bottom. I added a second layer of 10 oz to a boat with one layer on it when I upped it from a 5 hp kicker to a 25 hp. It helped quite a bit. That hull was 7mm okume and the boat ran about 18 knots. For the inside, I'd be tempted to go with a polyester fabric for maximum abrasion resistance and a bit more damage tolerance, at least on the tread areas. Ten oz glass completely filled with epoxy is plenty heavy for the interior and exterior topsides. I'd add a rub rail and sheer cap after glassing to absorb bangs and the worst of the UV. You don't want a glass-wrapped edge on the cap exposed to years of sun.
     

  15. LP
    Joined: Jul 2005
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    LP Flying Boatman

    With 10 oz. cloth, you will start to see the weave of the cloth, but it's not that noticeable. Your cedar will look nice with the bright finish. On the bottom, I feel a double layer of 10 oz will start to hide the wood so painted finishes in those areas would make more sense. Varnish doesn't like extended periods of immersion and so again more durable painted finishes are the logical choice on the bottom, inside and out. Maybe even some kind of non-skid surface on the bottom inside.

    -------------

    Nicec project BTW. Reminds me of the Dolly Varden (http://www.svensons.com/boat/?p=Utility/DollyVarden), but on a larger scale.
     
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