Minimum sized motor boat to round around non stop ?

Discussion in 'Boat Design' started by longcours62, Aug 22, 2013.

  1. longcours62
    Joined: Jul 2011
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    longcours62 Junior Member

    Since 1989 we still thinking it is possible to navigate around the world non stop with a (relatively) small motor boat.
    First proposition came from a friend with this uncommon type of boat.
    http://long-cours.62.over-blog.com/article-le-concept-77271358.html

    Later we thinking mono hull our actual boat was the final step of this way.
    Unfortunately for different raisons , mainly $$$ or €€€ we never try.
    Now I am thinking smaller and cheaper …

    And I looking just under 15 meters , but the first challenge is the possibility of a hull
    design able to support at full load around 26 t , said 6,7 t for alloy hull, 1,2 for engine ( and all around shaft, spare part ,tools, filter etc.) and 2,6 t for all the rest (small rigging, chain, smalls arrangement, food etc ) and 15,5 t of diesel (around 18600 lt).
    With 10% reserve the average weight ( between the start an the arrival…if arrival !!:confused:)of the boat will be 19 t.:mad:

    The question are :
    - a drawing able to cruise safely between 26 t to …12 t (weight at the end with just 10%)
    - able to use around 20 hp (less it is better of course)at a cruising speed of 5,5 nds for the average weight of 19 t ( in theory 20 hp at 6 nds could be around 0,68 lt per nm if all perform at the best…)
    - find better compromise between «*thin efficient*» and «*fat loadable*»
    just for get enough volume I arrive at 14,90m wl beam overall 4,6m, beam wl 4,15 m, draft full load 1 m,….but this characteristics are far from «*efficiency*» !!!:D

    In clear a hull able to cut the consomption of Arielle by 45% for cruise 2 kts slower withe 2,5 m more at wl and 6 t heavier at the start :eek:

    Ok some advices ?
     
  2. michael pierzga
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    michael pierzga Senior Member

    Non Stop ? Impossible.

    I run out of coffee after 4 weeks
     
  3. dskira

    dskira Previous Member

    I will interested of the finality of this adventure. Pleasure? Call of the high sea? Stock on a oil company? Want to be a chess champion? Motorship are soo boring, ask a crew on one, they will tell you.
    Classic diesel engines manufacturers don't have to prove anything anymore.
    Try to do it with an hydrogen engine. Ask Mercedes or BMW for help.
    That will be a first.
    Disclosure: I don't know nothing about hydrogen :D
     
  4. longcours62
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    longcours62 Junior Member


    May be just like wrotte Marin Marie 77 years ago : "J'aurais d'ailleurs eté bien embarrassé de lui dire l'interet que j'y voyais moi même. Je croyais la chose faisable, et je voulais le vérifier, c'était tout."
    Translated by Google : "I would also quite embarrassed to say the interest that I saw myself. I thought the thing feasible, and I wanted to check it out, that was all. ":rolleyes:
     
  5. longcours62
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    longcours62 Junior Member


    Never try Pomerol or "montagne St Emilion ? For replace coffee ?
    The problem with the vine ..it is the weight of a hudge amount of bottles !
    :p
    but the advantage you can send messages in bottle twice (at less ! ) a day :confused:
     
  6. Tad
    Joined: Mar 2002
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    Tad Boat Designer

    I think that, so far, Idlewild has made the longest small boat passage. Something like 5000 miles non-stop across the Indian Ocean (East bound). They travelled very slowly (< 5 knots over the bottom) on much less than the 50 installed HP.

    P1010043.jpg
     
  7. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    What a fabulous looking boat that is Tad.
    Would love to own that.
     
  8. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    I'd go with less Beam and maybe deeper draft.

    How about a 3.0m WL Beam and a 1.5M draft.

    Believe it or not, going that direction will cut whetted area, which causes friction drag, which is the major portion of your over all drag at that speed.

    Also, going narrower leads to less temptation to build up high with your superstructure.

    At an average power to weight ratio of slightly over 1.0 hp per ton, you have to cut down your frontal aerodynamic drag as much as possible, or you won't be able to make any headway at all against strong winds.

    Also, with more hull in the water and less above it, it will be easier to control in strong cross winds.

    The Olympic class ocean liners were able to get by with a little over 0.75 hp per displacement ton, but they were 260m ships that were only 32m wide. The laws of scale are working against you.

    You will be piloting what amounts to be a diesel tanker around the planet. It aught to look more like one than a fishing trawler or tug boat.

    Less Beam for given displacement and length means a more gentle roll at sea. That should also be a major consideration.
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    I'd be carefully studying oceanic currents and their direction and speed of circulation, as well as prevailing seasonal winds, not to mention areas of known pirate infestation, then decide not to proceed anyway !
     
  10. longcours62
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    longcours62 Junior Member

    Less Beam for given displacement and length means a more gentle roll at sea. That should also be a major consideration.[/QUOTE]

    When I read the crossing of Ideiwild from South Africa to Australia they wrott : Rolling 60° ! but I don't understand clearly if it is 60° each side or the total (30° starboard = 30° portside ) ?

    If thinks roll could be more gently :) or your stomacs is far stronger than mine :?:
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    If its 60 degrees either side of vertical, time to activate the EPIRB.
     
  12. longcours62
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    longcours62 Junior Member

  13. dskira

    dskira Previous Member

    The picture seams to be Yogi, which capsize due to large amount of water intake.
     
  14. dskira

    dskira Previous Member

    A New Zealand patrol boat was having 50 degree roll on each side in a very rough passage. And it is not extraordinary.
    Motor yacht can be quite lively for frail stomachs.
    The galley was closed.
     

  15. longcours62
    Joined: Jul 2011
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    longcours62 Junior Member

    Idlewis

    I don't find the article where they wrote 60°
    30° each side(total 60°) it is not uncommon on big weather but 60° each side it is a lot ...
    But on the same article they wrote : between South Africa to Australia they just eat "hot" just during few day ,the rest of the time they was not able to cook .:mad:
    Sure 60° each side kitchen is closed, or may be whith flying saucer !?:confused:
     
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