Boat waves - how many?

[DickR]

With the water quiet as a mill pond, and almost no boat traffic midweek this time of year, it's interesting to see wave patterns on the water. I've noticed that a fast moving boat, on plane, seems to make relatively few waves, and of course they tend to come in almost parallel to shore. The low angle of the wave relative to boat path of course is due the boat's speed.

This morning I noticed a small work boat type of craft moving slowly through a thin fog. Looking out over the water, each wave was identified by the change in reflected light at the low angle. It seemed that there were dozens of waves being left by the slow moving boat.

Wave speed, of course, is simply a matter of water depth and density (fresh vs salt). But can anyone shed some light on what determines how many waves a boat will make?

[Moderator: I ought to have posted this in General Discussion]