angle of mounting/working engine

Discussion in 'DIY Marinizing' started by brighttemples, Jul 6, 2011.

  1. brighttemples
    Joined: Jun 2011
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    Location: Bombay, India

    brighttemples New Member

    Hello All,
    I am a new entrant into the marine and boat design sector. I have questions regarding using a regular automotive/industrial diesel/petrol engines inside my hull. I am looking at using one of the above mentioned engines to drive my propulsion system.
    I have heard and read that automotive and industrial engines work only at a maximum angle from horizontal as the oil pump is not able to supply oil if that angle is exceeded. Is this right?
    The reason I am concerned abt this is because, I am design a planning hull and it might plane at close to 20-23 deg and I dont know if the engine will get oil via the oil pump if it is at 20-23deg from horizontal.
  2. Stumble
    Joined: Oct 2008
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    Location: New Orleans

    Stumble Senior Member

    Buy a marinized engine and follow the manufacturers recs. It will save you and you consumers a lot of money. In fact I wouldn't even consider a non-manufacturers marination job in a new or used boat. At least not without a huge discount for it.
  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    How can you be "designing a planning hull" with a 20 - 23 degree shaft angle? This isn't remotely possible (well it is, but it's a lot of engineering, just for crappy preformance figures) and any moderately skilled "designer of planning hull" forms would all ready know this. Why in the world would you even consider such an angle? Let me guess FreeShip? Which is why it's free. You can modify an engine to work standing on it's pulleys if you want, but the question still remains, why would you want to.
  4. ldigas
    Joined: Feb 2011
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    Location: Zagreb, Croatia

    ldigas Senior Member

    Marine engines usually have recommendations for static angles (in which mounting angle is specified) and dynamic (while-running) maximum angles. For example, static angles could be 2-3 degrees, while dynamic could be 7-9 deg. (just an example here from the booklet I have on my desk).

    20-30 degrees is definitely a very high value (unrealistic), not only for engine performance but for the operation of the boat in general.

    You say you are designing a planing hull? Could you perhaps show or describe what you have done so far, using what reasoning so people here can maybe clarify some small errors your design might have?
  5. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    15 degrees is the maximum shaft angle that is reasonable. The oil pan in marinized engines usually has the sump in the rear. Often the oil pump pickup is different.
  6. brighttemples
    Joined: Jun 2011
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    Location: Bombay, India

    brighttemples New Member

    First thanks for the replies.

    Well, to start of with I am quite a beginner when it comes to boat design. However, I am working on a R&D project for jet propulsion system for planning hulls.

    the 20-25 deg angle which I mention is based on some data which the hull fabricator predicted.

    Anyway, for my planning hull -I have total displacement (hull + engine + propulsion system + payload) of around 1.1 Ton. I want to use a 120HP engine and get the boat to 30+ Knots.

    Now, the engine I am talking abt will be the prime mvoer for my propulsion system. There are plenty of automotive/industrial engines available in market and so I wanted to see if I can use them.

    About static and dynamic angles - I found a Duetz marine engine - which can take the dynamic angle (i.e. during running) upto 40deg.
  7. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Look at a drawing of the engine you intend to use or unscrew the oil pan from one.
    You'll quickly discover what is the maximum operating angle.

    If there is a possibility that the pump draws air at the required angle, extend the suction tube to the lowest part of the oil pan.
  8. pistnbroke
    Joined: Jan 2009
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    Your engine angle is all about the design of the sump and oil pump pick up ...a land rover is designed to climb a 45 deg slope 24/7 and ford /rover engines from cars vans have been adapted for these vehicles so its up to your engine not intended to run at full output for long periods ..20% in a vehicle so think on that ...plain bearings not roller bearing .....

  9. Inboard
    Joined: May 2012
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    Location: Johannesburg

    Inboard Junior Member

    Check out the inboard motor installation book from GlenL it is a mine of info for inboards.
    I am fitting a flat six Subaru into a barrelback 19 which will sit at about 12degrees with 15
    Being the max
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