Surface-effect ship with water jet for towing operation?

Discussion in 'Jet Drives' started by MartinGrossmann, Oct 10, 2017.

  1. MartinGrossmann
    Joined: Oct 2017
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    MartinGrossmann New Member

    Hi, I am trying to learn more about this combination: Surface-effect ship fitted with water jet propulsion system performing towing operation. I am struggling to find any information regarding this topic. Do you have any theoretical ideas what are the limitations and advantages there? I wonder how would SES with water jet deal with this issue. SESs are usually very light ships and I can’t imagine what happens if they are about to tow a heavy object… danger of rolling over? Is water jet propulsion suitable for towing?
    Many thanks for any hints.
    Martin
     
  2. DCockey
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    DCockey Senior Member

    Why are you interested in this combination? Are you a student with an assignment?

    My recollection is the US Navy considered towing sonar systems with SES vessels in the 1970's.
     
  3. gonzo
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    gonzo Senior Member

    Towing is a slow speed operation. Why would you choose a surface effect ship? It's like buying a Formula 1 car for towing.
     
  4. DCockey
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    DCockey Senior Member

    My guess this is an assignment in a naval architecture class. Not intended as a serious proposal but rather to have the students consider the differences in various types of vessels and propulsion systems.

    An operator of a SES might want to consider towing by the SES in an emergency situation.
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    Picking up DC point- you need to ask yourself these questions:

    1 - what is an SES and how does it distinguish itself from a conventional hull.
    2- Why does it use waterjets
    3- Are waterjets suitable for bollard pulls
    4- what is being towed
    5- At what speed is it being towed
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    You can fish out of a helicopter in theory, but not very practical.
     
  7. MartinGrossmann
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    MartinGrossmann New Member

    Yes, you are right, it is a school assignment and the topic is to evaluate this ship design for operational requirements of emergency response and rescue boats. And one of the requirements is the towing.
     
    Last edited: Oct 11, 2017
  8. Ben Landgren
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    Ben Landgren Junior Member

    As SES is a fast craft, the waterjet needs to be for designed for high speeds, so it would not make sense to use one of those jet drives that are designed for low/towing speeds. Waterjets that are designed for fast crafts tend to have relatively poor efficiency on lower speeds and many of them cavitate on bollard pull/tow. For emergency and rescue point of view waterjets have the advantage of not having rotating underwater parts that might be a dangerous combination with people on water.
     
  9. BlueBell
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    BlueBell Ahhhhh...

    Look at what's important in emergency-response and in towing...
     

  10. BMcF
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    BMcF Senior Member

    In the last several years, SES designs for windfarm CTVs have been developed and built that have waterjet units sized to provide the required bollard thrust for pushing on to the towers yet still perform well at the 40+ transit speeds. The diameter of the selected jets is a good bit larger than would be installed were the low-speed thrust requirement not in play.

    Way "back in the days" of early naval SES development programs, multi-stage jet pumps and variable-geometry waterjet intakes were being developed and tested to make jet propulsion efficient and cavitation-free over a very wide operational range. However, those designs were complex and never matured to production hardware. That's not to say they could not be "resurrected" as a potentially enabling technology for purposes of an academic exercise.
     
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