drag coefficients of an oyster barge

[arn0]

Hello,

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":
http://www.navalu.fr/chalands-ostreicoles-aluminium

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,

Arnaud

 

[daiquiri]

Hi Arnaud,
perhaps this SNAME document can be of help: http://www.sname.org/HigherLogic/Sy...tFileKey=447d4293-087a-481d-88d6-1ad699d76326
See the attached test report too.
Cheers

 

[arn0]

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
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!

Arnaud