I looked and looked for hp equivilents when I was looking at one for my big AK drifter ... never found a good comparison. I chose a Minn Kota Riptide 74 and I zip along pretty well with five of us in the boat. The newest Cabela's shows a 48 volt version for a party pontooner and they rate it a 2hp ... that's a lot more power than I'm currently running based on the current draw and such.

With a 50-55 lb. thrust, you ought to have plenty of power for even a fast troll.