drag coefficients of an oyster barge

Discussion in 'Hydrodynamics and Aerodynamics' started by arn0, Nov 23, 2015.

  1. arn0
    Joined: Oct 2009
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    arn0 Junior Member


    I am looking to estimate the wave, form and viscous drags of a typical aluminium oyster barge.

    Those workboats are very common in France under the name "Chaland":

    typical lenght 12m & beam 3.5m.

    I guess they are actually planning when empty, but I am particularly interesed in low froude numbers, around 0,20 and 0,30.

    Would one of you have some data on those type of hulls ?

    Thank you very much,

  2. daiquiri
    Joined: May 2004
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    Location: Italy (Garda Lake) and Croatia (Istria)

    daiquiri Engineering and Design

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  3. arn0
    Joined: Oct 2009
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    arn0 Junior Member

    you're my hero

    Thanks so much, this is an amazing paper, I learnt a lot!

    it took me quite long to read it, since i didn't have the vocabulary, and too bad it is not in the metric system - nobody's perfect :p
    But i guess I understood most of it.

    Some differences I see with the oyster barge:

    - this study is ultra well documented on the effect of hull shapes on drag and stability of towed or pushed barges at Froude < .2 (with most of the study at froude .1), Lwl > 100 feet, B/T between 2 and 3.

    - where the oyster barge is self powered, more in the Froude between .2 and .3 (when loaded, because I guess they can actually plan when empty, can someone confirm ?), with LWL = 40 feet, and B/T around 10 with L/B around 3.

    I guess that :

    - the pushed or towed vs selfpowered only affects stability (but maybe it changes the apparent LWL ?)

    - the LWL>100feet doesn't change so much (only used in the "froude friction coefficient" page 18, which should be around 0,009 for 40 feet).

    - it seems hazardous to extrapolate the Rr/froude curves (fig 7 page 14) to froude 0.3.

    Thanks again!

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