The first step is to think of how much weight you will have on the board. For rigid boards if you will have under 160 pounds (paddler plus gear) the 10'6" is the way to go. Anything over that, 12' will be best. Keep in mind, it is easier for a smaller paddler to paddle a larger board, than a larger paddler to paddle a smaller board. With the Traveller boards, the longer the board the faster it will be. The 12'6" Traveller is best for smaller paddlers looking to get some good speed, while the 14' is best suited for taller paddlers looking for greater speeds. With the Rackham, the 12' gets the job done in most occasions. The 14' is really only needed in situations you'll be in very rough water or will have tons of gear, massive fish sold separately.