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Thread: Canoe capacity (again)

  1. #1
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    Default Canoe capacity (again)

    Time to revisit another topic that has come up before. Carrying capacity for canoes and similar boats - specifically for the lapstrake double paddle canoe I bought a few days a go.



    My question is whether it can reasonably carry myself, my wife and my four-year-old son. Total weight of paddlers and gear maybe 350-400lbs. I did my homework and read several previous threads on the subject, which gave me this formula posted by mmd:

    (Length in feet) x (width in feet) x 0.333 (average draft of a reasonably-loaded canoe, in feet) x 0.80 (average block coefficient of a canoe hull form) x 62.5 (weight of a cubic foot of fresh water) = total displacement of canoe plus cargo & people.
    This boat is about 16' x 30" and I estimate the hull weight at around 70lbs, so:

    (16 * 2.5 * 0.333 * 0.8 * 62.5) - 70 = 596lbs capacity. But looking at commercial boats of similar size that seems high. They are mostly rated around 500lbs. Even so it seems like a reasonable margin.

    I suspect the real proof is how it feels when we load it up - how much freeboard is left, how tender it is, etc. - but assuming reasonable freeboard (6"?), not too tippy and that we have enough room for everyone to fit is there any reason not to just try it out and see? With suitable precautions of course - protected water, PFDs all around and a test run with just myself aboard first.

    I haven't had a chance to get it in the water yet but I hope to do that in the next few days. Any advice would be welcome!
    - Chris

    https://fvpetrel.wordpress.com

    Life is short. Go boating now!

  2. #2
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    Default Re: Canoe capacity (again)

    You could test it for freeboard with some bags of wet sand first, before using live ballast.

    The block coefficient may be a bit high, or a lot high, try 0.3.
    Last edited by Peerie Maa; 05-08-2017 at 11:23 AM.
    It really is quite difficult to build an ugly wooden boat.

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  3. #3
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    Default Re: Canoe capacity (again)

    You could test it for freeboard with some bags of wet sand first, before using live ballast.
    Ah - good idea. Yes. Probably better to try it with sand bags first rather than my family. Who might not be hurt by a little dunking but who would probably prefer to avoid the experience! That's a plan then.
    - Chris

    https://fvpetrel.wordpress.com

    Life is short. Go boating now!

  4. #4
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    Default Re: Canoe capacity (again)

    Sure, that'll float the 3 of you, plus a lunch.

    Nice looking craft!

    I suspect it's not beamy enough to carry enough load for a week's backcountry canoe-tripping, for the 3 of you. Not without being immersed very deep, anyway.

  5. #5
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    Default Re: Canoe capacity (again)

    Quote Originally Posted by Dave Hadfield View Post
    Sure, that'll float the 3 of you, plus a lunch.

    Nice looking craft!

    I suspect it's not beamy enough to carry enough load for a week's backcountry canoe-tripping, for the 3 of you. Not without being immersed very deep, anyway.
    Thanks. It's not quite as nice close-up but it will do, and it's nicer than a plastic kayak. No worries on the backcountry load. Lunch for three is more the mark. I'll report back on how it does when we get it in the water.
    - Chris

    https://fvpetrel.wordpress.com

    Life is short. Go boating now!

  6. #6

    Default Re: Canoe capacity (again)

    Using freeship, a 6 strk dble ended generic 'carvel' hull schematically sim to yours, up to .8' displacement, fresh water, minus 70# hull wt:
    Useful load for
    2” displacement = 20#
    3” -----------------= 100#
    4” -----------------= 200#
    5” -----------------= 300#
    6” -----------------= 420#
    7” -----------------= 540#
    8” -----------------= 670#
    9” -----------------= 800#
    10” ---------------= 930#

    and no guarantees!
    bcmarinetrails.org - an attempt, by volunteers, to protect and enable 27,000 km of continuous camping and accesses along and around the whole Wild West Coast of British Columbia - for small beachable craft

  7. #7
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    Default Re: Canoe capacity (again)

    No worries, just do it.

  8. #8
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    Default Re: Canoe capacity (again)

    Quote Originally Posted by cstevens View Post
    Ah - good idea. Yes. Probably better to try it with sand bags first rather than my family. Who might not be hurt by a little dunking but who would probably prefer to avoid the experience! That's a plan then.
    easier than toting sand bags just invite a fat friend along for the first trip
    if i was closer i would volunteer
    Simpler is better, except when complicated looks really cool.

  9. #9
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    Default Re: Canoe capacity (again)

    Quote Originally Posted by Paul Pless View Post
    easier than toting sand bags just invite a fat friend along for the first trip
    if i was closer i would volunteer
    or maybe just someone with a weighty disposition, a great deal of "gravitas"

  10. #10
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    Default Re: Canoe capacity (again)

    Lots of info - thanks everyone. Daniel, how would one calculate the displacement of gravitas? Weight of dissertation in pounds divided by number of social media posts? Number of hours spend listening to obscure German expressionist composers less time spent listening to Katy Perry? Length of beard * the coefficient of beard form? (Long bushy beards having much greater gravitas than a goatee).... And would Daniel Schorr have received a special dispensation for excessive gravitas, requiring a waiver prior to embarking on any vessel?
    - Chris

    https://fvpetrel.wordpress.com

    Life is short. Go boating now!

  11. #11
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    Default Re: Canoe capacity (again)

    Quote Originally Posted by cstevens View Post
    And would Daniel Schorr have received a special dispensation for excessive gravitas, requiring a waiver prior to embarking on any vessel?
    Pretty sure you just lost Noyes.

    How I miss Schorr. . .
    Simpler is better, except when complicated looks really cool.

  12. #12
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    Default Re: Canoe capacity (again)

    Chris,

    PM me if you need an experienced 180# live weight and an active 40# non-shedding four legged passenger for testing.

    Alan
    https://sites.google.com/site/helium12sofsailboat/

  13. #13
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    Default Re: Canoe capacity (again)

    PM me if you need an experienced 180# live weight and an active 40# non-shedding four legged passenger for testing.
    Thanks for the offer Alan. I think I have a plan for evaluating the boat while keeping everyone dry. I'm hoping to get the boat in the water this weekend. We'll see how it goes.


    How I miss Schorr. . .

    Me too Paul. He would be a welcome voice right now. Probably better for him that he did not live to see the current state of affairs though. It would have been "deja vu all over again" for him I'm sure.
    - Chris

    https://fvpetrel.wordpress.com

    Life is short. Go boating now!

  14. #14
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    Default Re: Canoe capacity (again)

    Success! Got the canoe in the water today and it both floated and held all three of us with no problem.





    In the end the experiment was anticlimactic. I took it for a quick loop to make sure it would float and not turn turtle, then we all got in and went exploring. No sandbags or volunteers required (although thanks for the advice and offers of help!)
    - Chris

    https://fvpetrel.wordpress.com

    Life is short. Go boating now!

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