What size outboard motor should a 16 foot boat have?

I'm doing research on this as I write this. I'm contemplating the purchase of either a 17' or 19' Carolina Skiff. This is a fiberglass boat so it weighs a lot more than one made out of aluminum. Anyway, the important thing is how much weight are you normally going to be "pushing" around? You need to size your motor so that, when you have your maximum anticipated load on (disregard manufacturer's statements as to how many people the boat will haul), you can get the boat up on plane. The proper operation of an outboard motor depends on its' prop rotating at a certain RPM which is usually attained when the boat gets up on plane. Think of how your legs work when you are riding a bike. If you were to attempt to haul people on the back of it and do hills while in high gear, your legs would soon wear out. This is what will happen to your motor as well. If you want to stay with a smaller motor because of economy, you might want to consider going to a lower pitch prop as the motor won't have to work as hard. I've looked at many different boats and it seems as though the best way to find out is to go to a reputable dealer, explain what the boat is (aluminum, fiberglas, V hull or Jon boat) and let him recommend the engine. All boats must show a "Maximum HP" rating also. This is a "not to exceed" figure. If you have that number and are not going to load the boat down with 1000 pounds of gear and people my bet is that you would be fine with a 50HP engine.