Re: proper horsepower for 1947 Arkansas Traveler
HI Jim. I have a '59 14' aluminum, Arkansas Traveler that I run a '66 20 hp Johnson that pushes it along nicely (over 20 mph). I think you're boat may be a bit smaller, but I think you could run up to 25 hp safely, but I wouldn't go much more than that. Also, be sure your transom is nice and solid before you put a motor on. Replacing it easy enough, but there are a few rules when dealing with aluminum boats. 1.) NEVER use Pressure Treated lumber. The preservatives in it can cause and electrolytic reaction with the hull which will result in pitting and fatigues. Instead you should use quality, exterior grade plywood (or marine grade if you like) sealed with either epoxy or polyester resin and fiberglass. If you're not going to use the boat too much, you can get away with simply painting the new transom with a quality exterior grade paint like porch paint, I also like Rustoleum Professional Oil based enamel. The paint will by no means waterproof the plywood, but it should give you several seasons of use. 2.) Use Stainless Steel hardware dipped in 3M 5200 marine caulk, especially for any through-hull fittings such as the carriage bolts used to hole the transom in place. That's really about it.
As far as the motor is concerned, you may find that the motor sits a bit too low on the transom. Vintage motors of this era (50s-60s) had 18" legs that were a bit longer than modern "short shaft" motors (approx 15.5"), but shorter than modern "long shaft motors" (approx. 21"). As a result, they tend to sit a bit too low at times. You may want to build up the transom a bit in the middle to make up for this and/or use a jack plate to get the motor to just the right height. The cavitation plate should be level, or 1"-2" higher than the keel of the boat.
You're boat is an oldie for sure, but this link may help all the same. Glad there's another AT in the forums. Cheers!
http://www.fiberglassics.com/library/Arkansas_traveler
View attachment USCG HP rating guide.pdf (Official USCG HP rating guide for all boats)