tug boat engine mounts design (rigid? or flexible?)

Discussion in 'Propulsion' started by Brian.Lin, Nov 16, 2018.

  1. Brian.Lin
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    Brian.Lin Junior Member

    Dear All,
    a tug boat with a single 320kW main engine.
    estimated bollard pull is 13 tons.

    is there any suggestion on engine mounts?
    rigid? or flexible?
     
  2. Ad Hoc
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    Ad Hoc Naval Architect

    Estimated by who?
     
  3. TANSL
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    TANSL Senior Member

    And that, what is the importance? Can you, knowing that, answer Brian.Lin's question?

    How is the propulsion system, engine, transmission, propellers?
     
  4. Ad Hoc
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    Ad Hoc Naval Architect

    Oh dear oh dearie me...same old MO from Tansl

    So...you tell everyone to answer the Q...yet you do not practice what you preach....no surprises there... o_O

    So...please Mr Tanls...enlighten everyone...show me a vessel with a single engine of 320kW that has a 13 tonne bollard pull.
     
  5. TANSL
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    TANSL Senior Member

    Oh dear, oh dear, ... AH, even if you're right in what you say, that's not the point ("....no surprises there... o_O"). The OP, probably, would appreciate if you, and everyone else, answered his question. That's the only thing I wanted to clarify and, I'm sure, it's already totally clear so, oh dear, oh dear ..., the one that has nothing to say, please, to shut up (I already shut up).
     
  6. RonL
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    RonL Junior Member

    This boat had rigid mounts when built and in 40 years of operation is likely the same :)
     

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  7. baeckmo
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    baeckmo Hydrodynamics

    Since at least two of the possible solutions mean that the engine mounts will take the total thrust, it is relevant to ask who has "estimated" the bollard pull value, how this is done, and to what certainty. If TANSL knew anything about propulsion, he would have asked these questions when seeing the 13 ton figure given by the thread opener. If you don't understand why AH brought this to the surface, then you are not qualified to offer any advise on the subject. Misleading counseling can be dangerous!
     
  8. TANSL
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    TANSL Senior Member

    Okay, we already know that Brian.Lin (BL, hereafter) has given the wrong information. We, who know a lot, could tell the OP that for a certain range of powers the solution would be one or the other. That is, in addition to telling BL that he was wrong, one of us could help him to find the solution he was asking for. That's my point of view.
    This approach does not suppose to despise anybody, neither to BL, nor to AH, nor to myself, and, I am sure, it is more positive than to make clear,without more intention, that BL has been wrong.
    Although it has nothing to do with this issue, I can say that I have intervened in the design and construction of different types of tugs, with different types of propulsion. If I know something or I do not know anything about tugboats I think is not relevant for what we are discussing. The response of @baeckmo can lead the Op to give some more information that allows us to help him. AH's response does not help anyone. Knowing "who" estimated it does not lead to anything.
    Best regards to all.
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    And as stated before, endlessly (which is so tiresome):-

    Just endless verbal diarrhea and a waste of bandwidth.

    Precisely!

    See, proper qualified and experienced engineers understand the relevance of the question. As baeckmo posits succinctly:

    So Tansl, please, for the sake of everyone attempting to answer and assist, in your own words and intent:

    And let those that can contribute do so.
     
  10. Sparky568
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    Sparky568 Junior Member

    Don’t claim to be an expert in tugs either but I have some simple questions.

    What is the drive application? Straight shaft and prop? Shaft to Z drive? Diesel electric? Given the engine size could be either. I seen draggers in the400-450hp range with both. May ultimately be up to the engine manufacturer and their warranty.
     
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  11. Brian.Lin
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    Brian.Lin Junior Member

    Dear Ad and TANSL,
    sorry, my mistake for the bollard pull.
    the 320kw only have about 4.5 tons.
     
  12. Ad Hoc
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    Ad Hoc Naval Architect

    Still I reckon a tad high, but much more ball park value now, for an engine of that power.

    So, as baeckmo notes, where is the thrust, from the prop, transferred into the hull?
     
  13. Brian.Lin
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    Brian.Lin Junior Member

    Hi AH,
    we intend to use traditional propulsion system.
    main engine, reduction gear, drive shaft and FPP with Kort nozzle.
     

  14. Ad Hoc
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    Ad Hoc Naval Architect

    So...where is the thrust transferred into the hull..?
     
    rxcomposite likes this.
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