Pedal Powered Boats

Discussion in 'Boat Design' started by Guest625101138, Jul 14, 2008.

  1. Submarine Tom

    Submarine Tom Previous Member

    Rhinox,

    I'm thinking a used kayak with the potential for pedals.

    You could get a surf ski if you think you could learn to balance/paddle/pedal it.

    I know you're a very capable guy but do you think you're up for that?

    It would make a great pedal boat candidate down the road.
     
  2. Coach Dave
    Joined: Jun 2011
    Posts: 70
    Likes: 4, Points: 0, Legacy Rep: 40
    Location: Malabar, FL

    Coach Dave Junior Member

    Hi Rhinox,

    Good to hear from you again. Now that you have your input power estimated at 200 watts and you are thinking of building your own boat you have some key design decisions to make.

    1) What is your total displacement goal (weight of you, hull, drive train, seat). Are you making a solo, tandem, tandem + dog + food/drinks + gear?

    2) What hull configuration do you want? Mono, cat, tri? I am fond of narrow stabilized monohulls for reasons already discussed on this thread.

    3) Do you have size constraints where you store the boat limiting its length?

    4) Do you want to optimize for short sprint speed, a 1/2 hour run, several hour or all day cruise?

    5) Set an efficiency goal - maybe 75% of input power becomes your effective propulsion power.

    Once you specify these basic parameters you can use Godzilla to optimize the hull(s) and answer some "what if" scenarios.

    Dave
     
  3. Submarine Tom

    Submarine Tom Previous Member

    DIY often costs 2 - 5 times more than planned in money, time and collateral damage (emotional).

    Most don't make it all the way through to fruition.
     
  4. portacruise
    Joined: Jun 2009
    Posts: 1,114
    Likes: 32, Points: 48, Legacy Rep: 218
    Location: USA

    portacruise Senior Member

    Rhinox:

    There's no shortage of great, but idle HPboats for sale at discount prices- but connecting with the owners is the issue. Maybe post a "boat wanted" with your $1K limit to see what comes up on the HPB list:

    http://hupi.org/archives/hpv-boats/2012q2/date.html

    There was recently a Yamaha lakerunner posted for sale. Greg K's ocean boat is for sale and there have even been hydrofoils posted.

    Hope this helps.

    Porta

    "The pleasure of buying a boat is only surpassed when it is finally sold" :)



     
  5. I57
    Joined: Feb 2008
    Posts: 172
    Likes: 6, Points: 0, Legacy Rep: 62
    Location: Melbourne, Australia

    I57 Senior Member

    Tom
    I agree with your comment about cost of DIY. Also when estimating time to make it, take your worst estimate and multiply by 4.

    Rhinox
    Make your drive system first and then get a boat or build a boat to suit.
    Its a lot harder to get a hull and then try and get a drive that will fit and work.

    Ian
     
  6. Submarine Tom

    Submarine Tom Previous Member

    Thanks I57.

    I included time as part of my 2 - 5X cost estimate, same with mental suffering which comes in all forms of course.

    It's not true for everyone but is, unfortunately, common.

    Rhinox has agonised for years over what to build and hasn't even started yet!

    I see it as a real shame as this takes away from the time he could be spending on the water.

    He'll find his way.
     
  7. Coach Dave
    Joined: Jun 2011
    Posts: 70
    Likes: 4, Points: 0, Legacy Rep: 40
    Location: Malabar, FL

    Coach Dave Junior Member

    Godzilla run

    Rhinox,

    I did a Godzilla run assuming 435# total displacement (375# + 60# for boat & drive train) and 24' length with the search parameters pretty wide open. That yielded
    T (m) , 0.161042 (6.3" draft)
    B (m) , 0.337929 (13.3" beam)

    That is basically a 47% wider version of Rick's V11
    http://www.rickwill.bigpondhosting.com/V11.htm

    I attached a speed vs. power plot that shows 135 watts of effective power (input power * efficiency - parasitic drag from other under water elements and air resistance) required at 7 MPH. This should give you an estimate of an "optimized" monohull performance. I showed results up to 12 MPH to give you and idea of the sprint performance.

    Dave
     

    Attached Files:

  8. Submarine Tom

    Submarine Tom Previous Member

    Well that's pretty interesting CD. Can you give the graph a degree of accuracy?

    That would be right up Rhinox's alley... if he hadn't disappeared, again.
     
  9. Coach Dave
    Joined: Jun 2011
    Posts: 70
    Likes: 4, Points: 0, Legacy Rep: 40
    Location: Malabar, FL

    Coach Dave Junior Member

    Godzilla run

    I made the graph using the Godzilla / Michlet results. I did some searching and found a thread about the accuracy.

    http://www.boatdesign.net/forums/design-software/michlet-30472-3.html

    I don't have the instrumentation to test accuracy but Rick commented several times in that thread about accuracy. He designed several hulls with Godzilla / Michlet and seems to be pretty happy with the agreement between his measurements vs. the predictions. So I am thinking the graph should be "close enough". :)

    Dave
     
  10. Submarine Tom

    Submarine Tom Previous Member

    CD,

    Thanks.

    I concur.
     
  11. spidennis
    Joined: Feb 2007
    Posts: 519
    Likes: 11, Points: 0, Legacy Rep: 124
    Location: south padre island, texas

    spidennis Chief Sawdust Sweeper

    What do you guys think about the Shuttle Bike?
    http://www.shuttlebike.com/
    I got a bicycle trip in the planning stages ....
    gonna use a fat bike, and I have a few water crossings .....
    this might be just the ticket?
    It'll be a two week trip I'd guessimate.

    my only concerns is will a fat bike fit,
    and can it carry any weight?
    I got an email off to them .....
    most of the weight will be drinking water.
    I got to carry about 4 gallons for the longer stretches.
    I'll be unsupported except for re provisions at towns.

    yeah, by now I can build a similar device,
    and the cart I tow can also be the bike platform ....
    there's pros and cons of course !

    build or buy?
     

    Attached Files:

  12. portacruise
    Joined: Jun 2009
    Posts: 1,114
    Likes: 32, Points: 48, Legacy Rep: 218
    Location: USA

    portacruise Senior Member

    If your few water crossings are short, why not a packable, rowable, inflatable raft and find a way to carry the bike on it? The pictured bike conversion is inefficient friction drive to the prop and very high profile which is not good for crossing large distance of open water. There is a similar model made in Oz where you remove the rear wheel to get direct drive to the prop, but still high profile. The high profile might be ok in protected waters, some have used them on canal tours in Europe...

    Hope this helps,

    Porta


     
  13. spidennis
    Joined: Feb 2007
    Posts: 519
    Likes: 11, Points: 0, Legacy Rep: 124
    Location: south padre island, texas

    spidennis Chief Sawdust Sweeper

    Attached Files:

  14. I57
    Joined: Feb 2008
    Posts: 172
    Likes: 6, Points: 0, Legacy Rep: 62
    Location: Melbourne, Australia

    I57 Senior Member

    V15-i

    Been busy upgrading my boat from an inline shaft to a side mounted shaft. Same sort of setup Rick uses, have put on one of his folding carbon fibre props. Inline shaft was awkward for launching and transport. Put in a 52 tooth chain ring connected to a 15 tooth gear off a 90 deg 1:2 ratio gearbox.
    Shaft is 10mm dia aluminium 2.3m long. Gear ratio is 1:6.9 which gives me about 13-14kmh at 100rpm cadence, feels a bit light. Putting in a 14 tooth gear this week to bring the ratio up to 1:7.4, will be a bit harder to pedal but should give a higher speed. I can go to a higher ratio with a 13 tooth gear or even a 12 tooth gear but whether thats too high I'll have to see. Haven't changed the rudder, under the hull is the most efficient but dosen't let me sit the boat flat on the beach. Have to work out which is better a kick up rudder that is less efficient or stick to the one I've got.

    Ian
     

    Attached Files:


  15. GMR
    Joined: Sep 2011
    Posts: 54
    Likes: 1, Points: 0, Legacy Rep: 22
    Location: Nova Scotia

    GMR Junior Member

    Hi Ian,
    That is a great looking boat! It is a beautiful calm sunny morning here and would be a perfect day to be on the water..........if my boat was finished. Just wondering what the specs are for the prop you are using. I am building the cat first so my requirements will be different and I expect the single hull version will still be heavier and slower than yours.
    Cheers, Glen
     
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