So for slender beachcat hulls and kayaks the wave drag vs speed relationship seems to follow a sigmoidal curve (After 8 knots wave drag stays more or less constant). While for conventional displacement monohulls, the wave drag vs speed curve looks like there is a quadratic trend.
Is there a critical width/length ratio or critical width which determines the transition between these two very different relationships?
Or maybe the weight of the hull comes into play (the g in Froude number)?
I have seen people mention width/length ratios, but I have never seen anyone give a good reason why a certain ratio should alter the wave drag vs speed relationship dramatically.
