"Boards" are just the concrete slats that surface a boat launch. Assume they measure a foot across and the ramp is inclined at 25 degrees, then multiply by 0.42 for the approx WSE in feet above the base of the ramp.

This is unnecessary, of course. Up here we've gotten used to gageing the Duc simply by the number of boards. You see, it's possible to be both "book smart" and wise to the "real real world" at the same time.