Ok, finally I got it working! (almost drowned trying...)
But I still have some trouble with the variable types of the height fields "h" and "v".
Declaring them as BYTE or WORD to avoid any rounding the image distorts completely atfer the first few waves.
There also seems to be a direct relationship between gravity "g" and "friction".
g=0.2 and friction=0.1 works fine for the moment.
And I'm still not satisfied with my coloration, I think I'm somehow misunderstanding the way colors are calculated in Freepascal using RGB values, alpha and/or these strange $FF1234 numbers...
I added some code to load an image "wasser.jpg" into a TBGRABitmap and read the colors into another heightmap "hCol" to have it disturbed by the waves.
Still, I'm not totally convinced by the result and would like to improve the way any image is put behind...
Anyways, here's the code, have fun with it! :-)
Doc