It would catch everything, including canoes AND swimmers.water equiv to a spike strip on tires.
And it would get messy real quick... ever see a boat "nose in" at speed? The soft squishy humans get tossed out the front, to be pelted with shattered boat... and fuel tanks and coolers. Fun to watch... if you don't know anyone involved. I watched my cousin nose in, in an unlimited outboard hydro, at a bit north of 100mph... the biggest part of the wreckage was the transom, the rest of the boat was just GONE. Cousin didn't fare so well... he got hit by the motor, spinning at maximum revs