How fast is your boat? Do you know? Does the question even make sense? Isn't any boat going to go faster if you apply more power to making it move? What people really should ask is" "how efficient is your boat?"
What efficiency means is that for a certain amount of energy applied to making the boat move, you will get a certain amount of motion. A more efficient boat will move more with less effort. This could mean that for a given speed a more efficient boat will require less effort, or for a given effort, a more efficient boat will move faster.
Efficiency is typically measured as "drag". Drag refers to how much slowing force is created by the boat while moving through the water. More drag means that the boat will be forced to slow down more rapidly. A boat with less drag will go faster for a given amount of effort.
There are two main sources of drag on a boat. The one people with a little knowledge of boat tend to think of first is wake drag. This is a force created by the effort required to make the waves in the wake of a kayak. Most people are familiar with this idea through the term hull speed