Need Advise : Flat Bottom + V Seaworthy ?

Discussion in 'Boat Design' started by bingo, May 26, 2013.

  1. bingo
    Joined: May 2013
    Posts: 17
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Karachi

    bingo Junior Member

    We are thinking for a budget boat. Do you think this boat can be used on sea's with swells upto 3-4 feet @ 5-8 sec interval with winds of 8-12 Knots.

    Boat is 18' Long & 5'5" wide

    We are planning to use it as a dive boat and put up an 20Hp Yamaha 4 Stroke engine (already bought).

    Sincere advise will be highly appreciated ...
     

    Attached Files:

  2. Squidly-Diddly
    Joined: Sep 2007
    Posts: 1,455
    Likes: 54, Points: 48, Legacy Rep: 304
    Location: SF bay

    Squidly-Diddly Senior Member

    Sure, I've been out in homemade skin on frame kayaks in "bigger seas".

    But are you going to be overloading it, or loading it top heavy, or allowing everyone to gather on one side?
     
  3. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 471, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Agreed, that boat will do fine, though the boat's shape is less important than the skipper's abilities. 3' - 4' rollers aren't much to overcome, though it might be a wet ride, if powering very hard into them. The boat is fairly narrow for use as a dive platform, so she'll tend to roll around while parked over a spot in certain conditions, but hey, everything is a trade off of some sort. Most boats of that length will have 7' - 8' of beam, which makes for a more stable, static platform.
     
  4. Landlubber
    Joined: Jun 2007
    Posts: 2,640
    Likes: 123, Points: 0, Legacy Rep: 1802
    Location: Brisbane

    Landlubber Senior Member

    Sure, looks like Panga design type of boat, Google them for some incredible stories of seakeeping. The Pacific Islanders here use them for excfeptional voyages.
     
  5. bingo
    Joined: May 2013
    Posts: 17
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Karachi

    bingo Junior Member

    We have to put in
    6 Scuba cylinders(20Kgx6=120Kg),
    2 kit bags (80Kg)
    4-5 persons Max (60Kgx4= 240)

    Approx 500-600 Kg Payload .. I guess
     
  6. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 114, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    The Panga is a great boat. you will be happy

    20 hp is a bit small. you need a 40 to operate fully loaded
     
  7. bingo
    Joined: May 2013
    Posts: 17
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Karachi

    bingo Junior Member

    Well ... I under estimated this boat but still have doubts about it.
    Thanks for Pin pointing the hull design

    Do you think its worth buying for our purpose ... and would a 20Hp 4 stroke take it around 12 Knots with 600Kg pay load ...
     
  8. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 471, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    I don't think this is a Panga and I think this boat is a wee bit small for you needs. Maybe you'd be better off finding one with either more length or more beam or both. I also think your weight estimate is low. You'll have a 410 kilo crew load alone and haven't considered running tackle, spares and other essential items all boats take along. A 5.48 m by 1.65 m boat is going to be darn crowded, with guests, tanks and gear on a calm day, let alone in a pitching sea.
     
  9. bingo
    Joined: May 2013
    Posts: 17
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Karachi

    bingo Junior Member

    Yes the deck might be cluttered with gear, but we are on tight budget here.
    I think anything Bigger then this would render our 20Hp OBM useless.

    If it can handle the sea conditions, we can use it. This New boat is costing us US $3000
     
  10. bingo
    Joined: May 2013
    Posts: 17
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Karachi

    bingo Junior Member

  11. Mr Efficiency
    Joined: Oct 2010
    Posts: 7,759
    Likes: 272, Points: 83, Legacy Rep: 702
    Location: Australia

    Mr Efficiency Senior Member

    A lot of these things originated in Japan, for Third World/Pacific islands fishing and island hopping market. Too narrow gutted to be survivable in extreme conditions imo.
     
  12. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 471, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Particularly grossly under powered with a 20 HP outboard.
     
  13. daiquiri
    Joined: May 2004
    Posts: 5,372
    Likes: 239, Points: 73, Legacy Rep: 3380
    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

    60 kg per person is a bit too low estimate, particularly if you plan to carry western tourist divers. 75 kg is a weight per person commonly used in design calculations, but that too is an optimistic value, imo. 85-90 kg per person would be more close to an everyday reality.

    Sorry if I ask perhaps an obvious thing, but did you account for 7-10 kg of lead per each diver?

    I also agree with previous posters that going into an open sea on such a heavily loaded boat powered by just a 20 HP motor is not advisable.

    Cheers.
     
  14. bingo
    Joined: May 2013
    Posts: 17
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Karachi

    bingo Junior Member

    Agreed ... under-powered.... If we put in an 40-60 Hp diesel inboard .. do you think it will handle the sea
     

  15. Tad
    Joined: Mar 2002
    Posts: 2,300
    Likes: 176, Points: 73, Legacy Rep: 2281
    Location: Flattop Islands

    Tad Boat Designer

    Too big a load for this boat.....

    600 Kg will sink her 4-5", which is too large a freeboard reduction for the anticipated sea state. You need a bigger boat with higher sides. Also think about how you will get the water out once it comes in.....
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.