As someone who never taught physics but has raced boats for many years - the speed of a wave in water in knots is 1.34 * sqrt(L) where L is the wavelength. I don't recall the constants in metric.
This is independent of water depth - until the water gets below the wavelength. So keep the water to a decent depth and it'll be easier to understand.
You could of course have fun with soliton waves...
Andy