hey keeper,
welcome, i just joined too, about a week ago. i just got back into fishing after taking off several years. lots to learn.
anyway about your question: referring to "hull speed," do you mean the maximum speed that particular boats hull can attain no matter what power is applied or do mean other criteria ?
i ran a 28# trust on a square back canoe it was ok speed wise. it beat the heck out of paddling and was certainly faster.
these electric tooling motors are fractional at best and unless one gets into the big expensive 80# - 120#+ thrust, horse power is less than one. and the high power tm's require 2 -3 or more batteries. lots of weight too.
suggest you get the biggest one you can afford, a good deep cycle battery, and a good battery charger.
take a set of oars to have backup power. and a push pole if you would explore very shallow waterways.
silent running is a wonderful way to see, hear, and smell the nature of a body of water.
enjoy, wistex