Boat thrust force

Discussion in 'Powerboats' started by pa_ad, Oct 28, 2009.

  1. pa_ad
    Joined: Jul 2009
    Posts: 2
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: USA

    pa_ad New Member


    If a boat, with the characteristics is pushing against (pulling) a fixed object (speed is zero), what would be the pushing/ pulling force?

    120' boat
    draft 2.1 m (7 ft)
    propeller diameter 1.3 m (4.2 ft), non ducted
    installed engine power (one machine): 2000 kw
    percentage of engine power being used 0.3%

  2. Ad Hoc
    Joined: Oct 2008
    Posts: 7,043
    Likes: 969, Points: 113, Legacy Rep: 2488
    Location: Japan

    Ad Hoc Naval Architect

    For most "bollard pull" type of situations you get 750kg per 100hp
  3. apex1

    apex1 Guest

    Let me doubt you turn the prop with 6hp engine output!
    So, the answer is ZERO.........
  4. Submarine Tom

    Submarine Tom Previous Member

    I concur.

    0.3% of 2000kw is less than 5hp from the prop at best.

    If the prop does turn, it's not going to be pushing/pulling much.

    Why do you ask?

    Last edited: Oct 29, 2009
  5. CDK
    Joined: Aug 2007
    Posts: 3,324
    Likes: 148, Points: 63, Legacy Rep: 1819
    Location: Adriatic sea

    CDK retired engineer

    This must be a joke, and a bad one.
    Any engine at idle will deliver much more than 0.3% power.
  6. apex1

    apex1 Guest

    And we "experts" missed that, focussed on a serious answer.:D

  7. Submarine Tom

    Submarine Tom Previous Member

    Especially in torque from a diesel.

    Good call CDK

    Tom out.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.