Help with Propulsion

Discussion in 'Boat Design' started by standman, Nov 27, 2021.

  1. standman
    Joined: Mar 2015
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    Location: Cebu

    standman Junior Member

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  2. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    You had mentioned this in your original post -
    -------------------------------------
    Power will be from twin 360HP 2200 RPM Diesel
    ZF V drive 2.06:1
    Waterline length 45'
    draft 2ft
    beam at waterline 12'
    vessel weight about 13 tons loaded
    Target max speed 24 cruising 18 knots
    ---------------------------------------
    And she seems to be going along very nicely in your videos, congratulations!
    Especially after that huge setback from the storm - that must have been very upsetting (to say the least).

    Re your target max speed of 24 knots, what was your maximum speed on the trial?
    And is your vessel weight around 13 tonnes as expected?
     
  3. standman
    Joined: Mar 2015
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    Location: Cebu

    standman Junior Member

    Hi Bajan,
    Weight was within 200KGs. Only hit 18.9 Knots but can only go 2100 of the 2400 RPM engine rating which leads me to believe I'm overpropped.
     
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  4. tonipu
    Joined: Dec 2014
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    Location: croatia

    tonipu Senior Member

    what propeller you used on the end?
     
  5. Barry
    Joined: Mar 2002
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    Barry Senior Member

    A question
    When the boat is turning to starboard, the boat appears to tilt to port. This seems a little unusual.
    Any reasons why?
     
  6. standman
    Joined: Mar 2015
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    Location: Cebu

    standman Junior Member

    28D X 30P 3B
    I did make a mistake of telling prop maker of my max RPM which is 2400 amd not 2200 as I thought so we adjusted from 28d x 34.6p to this. I have had it repitched again and now it is 28d x 28P. I hope to do sea trials later
     
  7. standman
    Joined: Mar 2015
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    Location: Cebu

    standman Junior Member

    Until you pointed it out, I didn't notice. May be a rudder issue. We did make another rudder set with less surface and balancer and hope to do sea trials later.
     
  8. tonipu
    Joined: Dec 2014
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    Location: croatia

    tonipu Senior Member

    i think you will have cavitation with this 3 blade smal area propeller
     
  9. standman
    Joined: Mar 2015
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    Location: Cebu

    standman Junior Member

    55% blade area. why'd you think it'll cavitate?
     

    Attached Files:


  10. tonipu
    Joined: Dec 2014
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    Location: croatia

    tonipu Senior Member

    see the post 21 picture 3, it says check for cavitation
     
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