Chine & Spray Rail Geometry

Is there any hard data available that calls up chine and spray rail widths and angles with respect or in proportion to beam or some other relevant factor, or is this still decided empirically or by experiance and precedent.
I have not been able to find anything of note on the subject in all the text books I have been able to get my hands on like "Lindsay Lord" & "Peter du Cane"

 

Spray rails

Did you manage to get some leads - if so. please advise as I am seeking similar information for tunnel & mod vp hulls.

regards

nevd

 

I have installed and designed many of them. However, it was all trial and error.

 

As I know, there is not much on spray rails, as many fashinating aspects of boat producing/designing,each designer/architect/builder has it's own version (as for flaps, steps etc) and ideas he/she has developed with direct experience.
The only thing I know is 1 the rail must be parallel to the water plane in it's lower face, but then, it can also be a little bit down oriented,2 it shouldn't cover the entire lenght of the boat to reduce resistance...bu then it might be long all the way to the transom to prevent rolling 3 all the inferior intersection with the hull should be rounded to reduce resistence...4 I've ssen many kind of rails on fast boats and many different knd of them...

 

Carolina Sportfishermen have rails the whole lenght. They are integrated with a forward spray rail. I install them on lobster boats full length and they work fine. These rails are part of the chine.

 

spray rails

Thanks for your response Gonzo & Fede. If you come across anything else, please keep me in mind - particularly radius to hull (both at top & bottom of spray rail) and whether or not spray rail should be laterally parallel to water.

Thanks again

nevd