AdamLein's idea is good. You'll need a dinghy anyway for cruising, so get one now. If you're shorthanded, consider "hipping" the dinghy alongside, next to the cockpit, made fast tightly bow and stern. this will work in calm water, like in the harbor. Take it slow (since reverse, if you have one, won't be very effective), then let the dinghy trail aft when you get into open, or rougher, water (not too rough though, you don't want to swamp the dinghy while it's alongside).
Returning to slip with hipped dinghy, get your nose halfway into the slip, then let the dinghy trail aft. You should be able to pull yourself the rest of the way in with the mooring lines you left on the slip for that purpose. This idea would work "backwards" too, for when you're backing out of the slip. With the dinghy hipped-up, you'd be able to back your "flotilla" with at least some control.
When I was a kid, working around a boatyard, we used a small skiff/Whaler with 10-hp outboard, hipped up alongside yachts much heavier than yours, to shift them around the harbor, it worked well. Also, around then, I grew up with a *lot* of Atomic (and Utility) Fours, they worked fine and the gasoline wasn't a problem if you took the usual precautions (meaning get down near the bilge and sniff first). Less vibration than a diesel, and with a crank handle, you could even start them by hand if the battery was too low to turn the engine over.
Last edited by nolatom; 05-03-2010 at 11:27 AM.