Builders / Rebuilders handy info

Discussion in 'Boat Modification Journal' started by DANZIG, Nov 30, 2009.

  1. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Better yet stay away from qualifying yourself as an engineer capable of engineering home built boats.
    Stay away from plans that other people have qualified themselves as an engineer capable of engineering home built boats.

    Get your plans from a reputable qualified individual person or company.
    Build to the designer's plan unless he approves the changes.
    A good designer puts in quite safety margin on the engineering because of amateurs building.

    Do that and all that is left is using your head in the captain's chair.
     

  2. DANZIG

    DANZIG New Member

    Messages:
    6,672
    State:
    West Virginia
    "Better yet stay away from qualifying yourself as an engineer capable of engineering home built boats."

    Now, where would be the fun in that???


    From time to time these questions come up.

    I am working with the floatation question myself.
    Even without the formulas I can pretty much guaranty that what passed for floatation in my cuddy (at least by the time I got her) was not adequate.
     
  3. fishmonster13

    fishmonster13 Member

    Messages:
    700
    State:
    cincinnati,ohio
    well according to the formula they give for h.p. i can out a 140 on it:smile2:
     
  4. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I think any part of the boat has to stay afloat for like 14 hours.
    That could be a foot of the bow sticking out of the water.
    When you home build you can make em impossible to sink.
    The boat might be slap full of water to the gunnels but it won't sink and will stay upright foamed right.
     
  5. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I can take an 18 foot flat bottom dory and put a 150 on it with no problem structural wise.
    The problem comes when you open up the throttle.
    When a 70 will run it a scary 35MPH in a flat bottom dory what you think a 150 will do?
    It's not about what you can necessarily hang off the back of the boat without sinking it or breaking the transom. It's more about the hull and the speeds it can be safely operated at.
    I don't want to even see a flat bottom dory running 65MPH. Good way to die.

    This is how designers put their minimum and maximum HP's on boat plans.
    The calculations are mechanical. They aren't based off of hull speeds or common sense.
     
  6. fishmonster13

    fishmonster13 Member

    Messages:
    700
    State:
    cincinnati,ohio
    trust me i know way to much about mechanical calculations, i have an m.e. degree,:eek:oooh: just couldn't sit that long at damn desk with out falling a sleep, boring as hell, i'd much rather be tearing something apart and rebuilding it:big_smile:
     
  7. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I hate calculations myself.
    My state electrical was riddled with them.

    They act like an electrician pulls up to a house and pulls out a pencil and paper to figure out how small a service he can put on a house when in actuality we slap a 200amp on it and let it ride.

    I got one wrong on a calculation for a service on a 12 unit apartment building.
    I figured it all the way down to the size of the service when they were just asking for the total VA load.
    Why would I stop in the middle of a calculation in the real world?

    I always hated math unless I was counting money and that money was profit.
    I was starting to hate the test writers too.
    After 8 hours of that sitting in a hard plastic chair I barely had sense enough to drive home. I had to find a bar halfway home.
     
    Last edited: Dec 1, 2009
  8. Dredge

    Dredge Member

    Messages:
    754
    State:
    Arnold,Missouri
    I don't intend to build a boat,but I bought mine used,with no max H.P. knowledge.Thanks to your post,I now know I can run up yo 110 horses.Thanks.This is valuable information whether you build or buy used.(My boat is a 1988 Grumman,with no manuals or capacity ratings I can find.)
     
  9. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Your boat, your life. Go for it.