bpyhullgen silver bullet 4.8

Discussion in 'Boatbuilding' started by zukobo, May 6, 2021.

  1. zukobo
    Joined: Sep 2019
    Posts: 53
    Likes: 12, Points: 8
    Location: taiwan

    zukobo Junior Member

    Reducing the ribs above the waterline is a great idea.
    To be honest I'll probably just borrow my friends ~80lb (about 1kW) trawling motor to start with.
    I had thought about an outboard motor or something like that with but the way the interior space is enclosed I don't really want gas fumes in there. I could have had a separate compartment with a blower but for this build keep it simple.

    I have seen some commercially available trawling motors that are 160lb thrust they say equivalent to about 7hp - this could be interesting.

    I don't have any speed requirement and haven't done any analysis on drag or power required. Based on 1.35 x waterline length calculation the "hull speed" should be a bit over 5kt.

    For starting I'll take it to a lake with no current on a calm wind day and try with my friends trawling motor... If I can leisurely navigate a mile or two and camp on the water the objective is complete.

    Revisiting this before going on a river with any sort of current or longer journeys will be necessary.
     
  2. Dejay
    Joined: Mar 2018
    Posts: 720
    Likes: 136, Points: 43
    Location: Europe

    Dejay Senior Newbie

    According to hullcalc.xls you should be able to get going a 5 knots with 674 watts. Which is probably a bit optimistic but doesn't sound too bad. I would have thought the weight would make a bigger difference.
     
  3. zukobo
    Joined: Sep 2019
    Posts: 53
    Likes: 12, Points: 8
    Location: taiwan

    zukobo Junior Member

    I've never heard of hullcalc.xls - do you have a link or reference to where I can learn more about hullcalc.xls?
     

  4. Dejay
    Joined: Mar 2018
    Posts: 720
    Likes: 136, Points: 43
    Location: Europe

    Dejay Senior Newbie

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