Some one once asked me "What's the difference between a kayak that goes 3 mph and a kayak that goes 3.5 mph?"
I replied "the difference is that after 30 minutes the other guy is a quarter mile ahead of you!"
It is my experience that differences that would be trivial in other vehicles are huge in sea kayaks.
Yeah and I think it's mental too .. I've seen this with my recent experencies alone...
I rode the strongest part of flood last Saturday morning and made an over 8 mile cruise in about hour - ten. It's taken me as much as 2+ hours to do that same trip under harder conditions..