Efficient ocean cruiser

Discussion in 'Boat Design' started by DesioMedia, May 31, 2006.

  1. DesioMedia
    Joined: Apr 2006
    Posts: 17
    Likes: 1, Points: 0, Legacy Rep: 11
    Location: Bangkok, Thailand

    DesioMedia Junior Member

    Hi

    I'm looking for some information about a long narrow dispacement ocean cruiser of about 60'-80'. I would like to use the boat as a live aboard for my ocean videography. I would lke the boat to be fast, efficient, and ocean worthy. I am willing to trade space onboard for these things. Hopfuly I would like a top speed of 30kts.

    With my criteria I think a long, skinny, low, light weight boat would be the best. However I have been reading and am wondering about putting a long sharp bulbous bow on the front in order increase wetted surface area. In addition with a sharp bulbous bow I could have a tall wide and deflectiave bow inorder to deflect water in bad weather. I got this idea form the Mathew barney film Drawing restraint 9, A crazy film. One of the actors travels to the Whalingboat on a 30'-35' foot narrow fishing boat with a sharp bulbous bow that extends about 8' out.

    I haven't seen this type of hull any where was wonderign about it
    Any Help

    -Alex

    Possiably something like this execpt with a sharp blubos bow taller hull and a long range cruiser deck.

    [​IMG]
     
  2. marshmat
    Joined: Apr 2005
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    Location: Ontario

    marshmat Senior Member

    When I think "fast efficient 80ft ocean cruiser", I think Dashew FPB-83: http://setsail.com/dashew/do_PARADIGM.html
    30kts in an 80' would be a speed-length ratio of 3.37, awfully difficult to do without climbing at least partly to plane. This would require a LOT of power, perhaps twin 1200hp diesels. If you can tolerate 14 knots, you can probably get by with twin 150-200hp motors.
    I think the "sharp bulbous bow" you refer to is a form of the wavepiercer concept. The idea here is that instead of riding over waves, you have a very fine bow that cuts through them instead. Most power wavepiercers are cats or tris. Some sailing monos (ie. VO70) use a similar concept. Such hulls need to be very long and thin, and are hard to fit much stuff into. The physics involved in making them work is horrendous, and successful implemetations usually have at least a couple of Ph.D's behind them- it's awfully easy to screw it up. Conventional bulbous bows, which essentially trick the bow wave into taking a less wasteful shape, work best in the pure-displacement speed range and only add drag above that range.
     
  3. Wellydeckhand

    Wellydeckhand Previous Member

    That is a nice cruiser without a doubt, money afterburner:)
     
  4. tom28571
    Joined: Dec 2001
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    Location: Oriental, NC

    tom28571 Senior Member

    Matt,

    I am sure that you are trying to be diplomatic but someone really needs to take Alex in hand and discuss some realities.

    Maybe have him list the top priorities and then offer some proposals to realize them if they are practical.
     
  5. DesioMedia
    Joined: Apr 2006
    Posts: 17
    Likes: 1, Points: 0, Legacy Rep: 11
    Location: Bangkok, Thailand

    DesioMedia Junior Member

    Ok thanks for the help.

    I now see that for what I want 30 knot top speed is out of the question. My math for a hull speed was very wrong (using 2.5x square root fo 80 ft). I can live with 14 kts with such low hp engines. The Dashew seems to be a large version of what I want.

    My needs are as folows
    1)Efficiency
    2)Bad Weather worthy
    3)Saftey
    4)Speed

    The boat I would be used as a live aboard for my ocean videography. We often travel to exotic locations around the world and shoot films underwater. I have a crew of 5-6 people. We have a 16' RIB we carry. Sometime we need to get to a place fast inorder to catch an event. Thoes are the criteria.

    Thx
     
  6. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    The Dashew is ez to love ,but a bit pricy to purchase and operate.

    Longest nonstop passage by a trawler yacht has been completed by Idlewild, shallow-draft 55-footer design by George Buehler.

    4495 nautiacal miles at 6.4 kts burning 1.39 US gph (4.57 mpg) from East London, South Africa to Fremantle, Australia.

    Here's the link to her site again. Lots of info and photo's.

    http://www.idlewildexpedition.ca/

    A bit better for the billfold.

    FAST FRED
     
  7. Wellydeckhand

    Wellydeckhand Previous Member

    Narrow hull and small engine will really get you far........ but cant outrun anything in reality............... 1.3 gallon still a lot yes?
     
  8. FAST FRED
    Joined: Oct 2002
    Posts: 4,519
    Likes: 111, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    ............... 1.3 gallon still a lot yes?


    Not really , it probably translates to 30 hp , not a lot of power to move a 55ft boat in open ocean..

    FAST FRED
     

  9. Wellydeckhand

    Wellydeckhand Previous Member

    They in Japan wonder they would go to China:D:D:D............ But the idlewild is very slim boat....... it seem the whole family is with the boat isnt it to much load for a small boat on a 1.3 gallon per........... :)

    WDH
     
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