I have a 1978 CP-16, and have used a $5 trolling motor that was a 20lb trust. It worked great until head winds where above 10mph. Yes, $5; I got it at a yard sale. I only needed it for a few hundred yards to get back into the marina.
I got a 55lb trust trolling motor from New Port Vessels at Thanks Giving and can handle head winds up to 25mph. I made a point to test it before I needed to use it, against head winds, getting back to my boat slip.
The Motor was $199 and free shipping with fast delivery. Talk to Amos, (866)-721-0002, 55lb trust, NV series and has a battery charge indicator on the top of trolling motor. Also, has 50 amp fuse included, which you may or may not use. The trolling motor has 5 forward and 3 reverse speeds. Speeds 1-3 will push a CP-16, 1978 model for a long time with head winds 15mph or less. Speeds 4 & 5 will push the boat good in 20 - 25 mph winds but I wouldn't expect a marine battery to last for more than an hour at number 5 speed. This is just my experience, so test your boat and motor setup before you really need it to get you out of a pickle.
Anyway, I hope this post helps someone looking at the pros and cons between gas or electric. I think any 55lb trust trolling motor should work for a CP-16. I don't have the long range that gas motors do but I have the power I need at the turn of my wrist.