Small Boat Drag Question....help!

[Biomechanist]

A quick question about small boat drag. We are using Reynolds Number vs. Froude Number graph to get a drag coefficient to plug into our main equation and find out the actual drang of our boat.
The problem is that the graph we are using is for huge ships...and so we are getting wrong numbers. We were wondering if someone could get us a graph or a site online that has a graph for Froude Number vs Reynolds Number for smaller boats like kayaks ets.
We would really appreciate that.
Thanks
BioMechanist

[tspeer]

You don't say what kind of boat you're interested in. Re vs Fr is an interesting approach, but would be highly dependent on the wetted area for the displacement, etc.

For sailboats, take a look at
http://www.rina.org.uk/rfiles/HISWA/...resistance.pdf
http://www.curtin.edu.au/curtin/cent...8/bmcrae1.html
http://www.curtin.edu.au/curtin/cent...8/bmcrae2.html
http://www.curtin.edu.au/curtin/cent...ernyacht98.pdf

For slender hulls, see
http://www.cyberiad.net/michlet.htm

[jehardiman]

If you are after Cf, why not just calculate it directly with the ITTC line. Or are you trying to use some of Froude's "circle" factors for a given "shipshape" hull? Better to use Taylor's data from a modern re-analysis or one of the standard boat hull series out there if you are doing something small.