OK, I appreciate it all depends, but... Let's say, a 16 foot canoe with two male paddlers of average abilities, not busting a gut but not having a nap either. Sort of enjoying themselves. Maybe with a shandy or two. Flat still water, no wind - e.g., a loch on a quiet day. A multi-day trip, in summer in the North (long days, then). Camping gear.
Don't know, did I cover all variables? Ah, yeah, wooden paddles, the canoe is green and one of the paddler's name is John.
What would you say is the average daily mileage?