Drive line questions..

Discussion in 'Inboards' started by Johan@sea, Feb 26, 2012.

  1. Johan@sea
    Joined: Feb 2012
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    Johan@sea Junior Member

    Hello to all, I Just signed up. So im new here but i have been around looking a lot before..
    I have some questions about driving a prop/boat and a high power pump by one engine. I have search the web and come up whit some ides, the right ones im not sure, and Im hoping u could help me out..
    Here I where I stand:

    I have a boat that will be fitted whit a 300 to 400 hp inboard diesel enging. I haven’t bought any engine ore driveline but a used engine is what im looking for.. The driveline will be an “in line”, I think its called. Engine mounting will be rebuild so there is some flexebilety..

    The pump need 100 to 150 kw.. (300 bar and 130 L/min and above) so a normal pto is to small i think..

    These pumps come whit different rpm options and whit or whit out different reduktiongears. And can be driven from the right ore left side. So they will “always” fit somhowe.. The pump does not need to be driven at the same time as the prop. If I can it would only be done at wery low loads on prop and pump.

    So Im looking for some way of mechanic connecting to the crankshaft or gearbox. No hydraulic, No beltdrives..

    #1 At the back end of the main shaft of the gearbox, on a drop-down ore angle-down gearbox, If that is possible.

    #2 An engine mounted split shaft pto , if they exist for marine engines? I know they use them on firetrucks for driving the truck ore the firepump..

    #3 At the front end of the enging. If the engine/crankshaft can deliver that much power at that end. It would also mean that the pump would be in the engine room instead of in a aft room. These pumps sometimes leeks, but a box of some can could be build..


    # 1 and 2 is my favorite when it comes to space on the boat. # 3 I like because I have used it before on a smaller engine and a smaller pump but it would really mess up the engine room .. The pump would be driven more then the prop , so nothing close to the limits when it comes to different ratings.. That’s why I think a normal pto would be to small?

    I have looked around here and found some info but not much , maybe i dont know the right words for what i need...


    Any opinions an ides are welcome, thanks..
    Johan
     
  2. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Hi Johan and welcome! There are marine reduction gears (forward/reverse) with a power take-off available. Check with IRM, Hurth, TwinDisc, Technodrive, et c.

    Normally the auxiliary shaft comes out above the propeller shaft, and there are various gear ratios for both shafts.
     
  3. Johan@sea
    Joined: Feb 2012
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    Location: Brasil

    Johan@sea Junior Member

    Thanks baeckmo..

    I have search the web, but the info u get from those companies isn't great product names and their pages are easy to find, but to make sens of whats there isent .. Sens i don't yet have engine ore pump I'm locking for general info..

    The reduction gears you think of , how do they work? Can u start/stop the pto whit a "lewer" ore does it always run. does it drive the prop ore the pto ore both at the same time? How much power can u take out , the same amount as to the propshaft? Do u have to stop/start the engine to shift?

    And are these "normal" products ore high price special things?

    Thanks again
     
  4. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    You can't specify the transmission until you have calculated the shaft RPM you need. That will determine the gear ratio. The shaft RPM is determined by your HP, propeller design, hull speed target and hull resistance.
     
  5. Johan@sea
    Joined: Feb 2012
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    Location: Brasil

    Johan@sea Junior Member

    Hi gonzo , I agree whit that statement, normaly..

    But this is not a new boat that will be designed, and the main engine will not be specified for the boat.. The most inportant thing is that it can drive the pump.. The pump will at times run all day.. So the engine/pto need to be sized for that.. something like 100kw is needed at the pumps end.. the pump comes whit ore whit out different gears.. so a rpm of 1200-2000 ore about 400-600 is what i need.. 100 kw at low rpm i think will give to much torq..

    How it works whit the boat is of second interest.. I will shop for a used engine. There is not a budget to custom build this system to an optimum.

    So is there a pto for this.. I have looked at the suggested web pages , and did not find any.. I have E-mailed Volvo Penta , ZF and Yanmar , they dont seam intrested in helping if they dont smell mony..

    Thanks
     
  6. philSweet
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    philSweet Senior Member

  7. Johan@sea
    Joined: Feb 2012
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    Location: Brasil

    Johan@sea Junior Member

    Thanks Phil..

    It seams that firefighting trucks use this .. And in some 4wd options for trucks , ect.. And this might be the option as it my be i can find something used that fit , ore can be made to fit..

    I was sure there was some "marine" version of this.. I have been a mecanic but i dont know a lot about transmissions in boats..

    Take care ,
     
  8. Johan@sea
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    Johan@sea Junior Member

    here is one pdf file..
     

    Attached Files:


  9. Johan@sea
    Joined: Feb 2012
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    Location: Brasil

    Johan@sea Junior Member

    after lots and lots of idees it seam that the easiest the solution is a V-drive whit a front mounted PTO.. Using a Twin disc SP-211..

    It seams like a Volvo Penta D9 can deliver the power needed that way..

    Just if someone els is reading all this..
     
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