[alanw]

The energy needed to increase speed is exponential, like Mr. Nice Guy said. For my wide kayak, to go from an easy 2mph paddle up to 3mph might take a little bit of effort, but to go from 3mph up to 4mph might take so much extra effort that it's not practical for anything other than short bursts.

Look for a yak with a fast hull speed if you're concerned about speed and distance. A PA probably isn't it.