Why are submarines poor sailers?

Discussion in 'Boat Design' started by misanthropicexplore, Jul 30, 2018.

  1. misanthropicexplore
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    misanthropicexplore Junior Member

    World War I and II submarines spent most of their time on the surface. From what I've heard they were terrible to sail. This is strange to me because when sailing, they have a lot of features that are generally associated with sea-kindliness:

    narrow,
    double ended,
    low windage,
    high displacement ratio
    wave peircing

    Why were they such lousy sailers on the surface? Low polar moment of inertia? Would a submarine bulb keel and heavy rigging be a good sailer? Insufficient rudder since half the rudder was out of the water? Lack of form buoyancy from the cylindrical hull?
     
  2. TANSL
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    TANSL Senior Member

    Among other things that could be commented, the submarines have so much buoyancy that they need to load a large amount of ballast to submerge.
     
  3. Ad Hoc
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    Ad Hoc Naval Architect

    More simple than that. Hint: think transverse stability...
     
  4. misanthropicexplore
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    misanthropicexplore Junior Member

    I wouldn't think that too much buoyancy would figure in, because more than any other ship, the submarine's buoyancy can be "dialed-in" to whatever you need.
     
  5. upchurchmr
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    upchurchmr Senior Member

    What submarine has ever been used as a sailboat?
     
  6. misanthropicexplore
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    misanthropicexplore Junior Member

    I just meant under way on the surface.

    If you want be really technical about it though, Argonaut II was a 66' motor sloop, the British used a 1 man wet sub (Motorized Submersible Canoe) in WWII. Neither really have anything to do with what I was asking about though.
     
  7. upchurchmr
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    upchurchmr Senior Member

    Sub hulls are essentially round. That doesn't keep them from rolling.
    The hull also needs to sink - without taking on too much water (ballast).
    That means the hull is deep in the water. What you see in WW2 was an exterior deck which flooded when it submerged.
    Waves would easily roll over the deck, making it useless for anything but calmer water, or extreme need.
     
  8. Doug Lord
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    Doug Lord Flight Ready

    Underwater modern subs are incredibly fast almost as fast as the fastest sailboat ever to sail-or so I've been told. But now I realize you meant on the surface-sorry.......
     
  9. upchurchmr
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    upchurchmr Senior Member

    Modern subs on the surface are not fast at all.
     
  10. Mr Efficiency
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    Mr Efficiency Senior Member

    I'd reckon they were "lousy" conveyances because the people inside were not in a very well ventilated space, and had no external point of reference, like the horizon. I'd be interested to know what input of fresh air there was, when surfaced, to counter the diesel fumes. These things turned into the coffins, of about 3/4 of German sub crews. Suffer, then die ! That is the real "lousy" part !
     
  11. upchurchmr
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    upchurchmr Senior Member

    Diesel fumes went directly up the snorkel and over board.
    Not to say there would certainly be some leakage - I wouldn't have liked it.
    Air intake for the diesel came from the living spaces, which were fed air from the forward part of the snorkel.
    Those boats were extremely small, with the sailors living "between" the equipment.
    No facilities for washing clothes, little water for washing people.

    Not being able to see the sky while wallowing along on the surface would have put me to puking very quickly.
    Modern air scrubbers did not exist back then. All kinds of nasty chemicals in the living spaces.

    Truely tough, dedicated men who served.
    My uncle was one. He served on 11 subs, 8 of which ended up being sunk. He would not talk about it at all.
     
  12. Mr Efficiency
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    Mr Efficiency Senior Member

    One can only imagine the harrowing scenes aboard submarines in combat, that would have made issues of seakindliness seem minor. Many would have "lost it" under bombardment from depth charges and the like.
     
  13. portacruise
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    portacruise Senior Member

    Search designer Vlad Murnikov "speed dream" and "Fazisi" . Possible 50 knots and round the world record speculations...... very long and low freeboard inspired by a sub. But a lot lighter weight compared to the old Subs

    PC
     
    Last edited: Jul 30, 2018
  14. misanthropicexplore
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    misanthropicexplore Junior Member

    Hey, it's a monomaran!
     

  15. JamesG123
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    JamesG123 Senior Member

    waikikin and Doug Lord like this.
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