Hypothetical boat question, power needed to shift a hull..

Discussion in 'Boat Design' started by WMitty, Jan 13, 2022.

  1. WMitty
    Joined: Jan 2022
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    Location: Isle of Wight

    WMitty New Member

    Hello guys. This a complete fantasy but I’m curious.

    When I win the Lottery, I will be wanting a boat like the Seacor Leopard/Lynx.

    I will not be wanting to travel at 42 knots, nor burn 750 USG ph.

    What power would be needed to propel the boat at 6/7 knots, 10 knots, and 16 knots?

    My imaginary boat would have 4 engines, much like the current layout, but smaller, perhaps two hybrids, and two straightforward diesels.

    I’ll try to upload images and specs.
    upload_2022-1-13_17-33-23.jpeg


    upload_2022-1-13_17-34-14.jpeg


    Ok, so I’ve lost the specs page. I think* it’s just under 200ton displacement, 190 feet long.
     
  2. WMitty
    Joined: Jan 2022
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    Location: Isle of Wight

    WMitty New Member

  3. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Welcome to the Forum Walter (I am guessing this is what the 'W' stands for, with a surname like Mitty :) )

    I know that this is a complete fantasy, but when you win the lottery, and commission the construction of this vessel, what do you then intend to use her for?
    Will she still be a crew boat, but working at slower speeds, or do you like the hull shape for a private yacht, with lots of room on deck for carrying 'toys', or ........??

    You need to develop your Statement of Requirements in more detail (never mind that it is a fantasy), including how much time you estimate (roughly) you will be travelling at 6, 10 and 16 knots (and the distances that you have to cover) - you might well find that another type of vessel will be more suitable for meeting these requirements.
     
  4. Ad Hoc
    Joined: Oct 2008
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    Ad Hoc Naval Architect

    In addition to Bj reply above - all very valid the SOR if you need a more realistic reply.
    However on pure numbers alone, the LD ratio is circa 7.0, so at low Fn (speeds) it wont take much to push her at 6 knots....but as Bj notes, for what purpose etc? It would be like buying a Ferrari to just potter around town below 20mph all day.
    But, where on the IoW will you be able to berth her??...can't see you getting her into Bembridge, especially on a low tide :oops:, Cowes, hmmm.. turning may be an issue too the farther down the Medina you go :(
     
    Last edited: Jan 13, 2022
  5. WMitty
    Joined: Jan 2022
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    Location: Isle of Wight

    WMitty New Member

    It’s all fantasy. I win the lottery and want to mooch about on a boat. I’ve picked the style because it’s efficient, or so I’m told, and it needs to be a useful boat, not a “white yacht”.

    Perhaps I should say what I want to avoid. Speed, unless there’s a situation that requires it. Fuel consumption, because boats are shockingly bad at eating the stuff. Planing hulls, because I don’t want to have to tell my passengers to hold on for their safety. Looking like a rich man. The boat should fit in to a working harbour with all the other boats, not look like a pampered palace.

    SOR, which is flexible, is for a multi-purpose work boat, 12 cabins, galley and stores for 12 passengers for 1 month at sea. It could support divers collecting ghost nets, carry out sub sea surveys, or go from one bay to another researching the temperature at which the beer is served in each taverna. Important research. It could borrow the Red Jet terminal and collect passengers for fishing trips, noodles to the needles trips, or play a game of getting round the Island using no fuel, without sails, using solar charged batteries. Does that make the SOR clearer? About 16 knots for avoiding storms and getting to fires or disaster spots that need the water makers. About 6 knots for the most economical movement possible, because speed is for people in a hurry. The only toy is a tender, unless someone wants to transport their submarine somewhere. The name’s Mitty, Walter Mitty.
     
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  6. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    This 50 m. catamaran humanitarian support vessel might meet some of the requirements in your brief above, so it could perhaps be a useful reference for developing your design?
    Project Echo: HSV Humanitarian Support Vessel - Echo Marine Group https://www.echomarinegroup.com/humanitarian-support-vessel/

    And M/Y Charley appears to be a slightly more 'yachty' version of the above -
    51m Catamaran Adventure / Support Yacht - Echo Marine Group https://www.echomarinegroup.com/51m-catamaran-adventure-support-yacht/
     
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