ETEC Low Speed Operation

Discussion in 'Outboards' started by fritzdfk, Aug 2, 2016.

  1. SukiSolo
    Joined: Dec 2012
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    Location: Hampshire UK

    SukiSolo Senior Member

    The thing is that a light V or RIB will swing around sideways (at very low speeds) in a seaway, even if the prop is constant speed. This sideways motion becomes the 'upstream' motion too. A more displacement hull or semi displacement will not swing as much so pick your poison. I can assure you that the stern on a 6m RIB will go sideways by it's own beam at sub 4 knots quite happily on moderate (Force 4/5) UK seaways...;)

    As we are not informed of your hull type it is difficult to assess much more. Hull speed in what conditions? Flat water no wind, or 2m sea and Force 7/8? This will give diferent sums to work out.
     

  2. rnlock
    Joined: Aug 2016
    Posts: 242
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    Location: Massachusetts

    rnlock Senior Member

    oops, this was in reply to Gonzo's post about engine inefficiency

    Not to mention the pumping losses. The engine has to drag the air it DOES get past the throttle plate, and then push it out against atmospheric pressure. I don't know just how significant this is, but it's part of the picture. I guess I could calculate it, approximately, but I'm too lazy.
     
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