I have an 18 ft. Lund Fisherman with a Yamaha F115 motor. I'm
thinking of upgrading to the new Yamaha F150, the maximum rated hp for
my boat. My boat's top speed now is approximately 40 mph w/2 people
and gear. I mostly use the boat for fishing, but there's some
occasional waterskiing.

What kind of performance increase could I expect by adding 35 hp,
assuming comparable props?

Any ideas on the trade in value of the 2000 F115? I'm trying to
decide if there would be enough of an improvement to justify the cost.

Thanks.