Rules, Rules, Rules - for a free country, there sure are a lot of GD rules.

Not telling you to do it - but I would try it, especially if the PD can't even tell you either way.

The "intent" of the sign is to stop, dirtbikes, snowmobiles, powerboats, water skiing, etc

Seeing how you would lose a race with a canoe or a kayak - no harm in trying IMHO. Anyone asks - tell them how you called the PD.

The Anglers Guide doesn't mention no motors, nor does the Boaters guide. I think you're good to go.