I believe there is an inherent design flaw with many older sailboats with full keels and keels that are part of the tiller assembly. These boats all seem to sail quite well, but under power, especially in reverse, their performance and maneuverability falls off dramatically. The boats that seem to perform best are those where the keel is situated a good distance from the prop. To me, this makes perfectly good sense.
Prior to 5 years ago I was strictly a powerboat guy. I've owned loads of them, both outboard and inboard powered, and even in nasty wind situations I was always able to back into a slip. With the inboard powered boats, all but two of which were single screw boats, the basics were the same as any sailboat--you had to have movement in order to obtain steerage. The difference was that there was nothing impeding water flow or propulsion of the prop. If the boat was sitting dead still, and you put the transmission in reverse, the boat would initially experience prop-walk. Within a few seconds, the prop-walk was overcome and the boat began to travel backwards--not sideways. Keep in mind that the rudders of most power boats are relatively small in comparison to sailing vessels so there was far less resistance to the water for overcoming prop walk.
Now, here I am 5 years later, When I was 65 years old, and I purchased my first sailboat. That was 5 years ago. My wife thought I had completely lost my mind, which still may be the case--the jury is still out on that one! I purchased a 1978 27-foot Catalina, a boat that needed a fair amount of work, most of which involved lots of elbow grease. The first trip I made on the boat was with Sheriff, who at the time was my sailing instructor. Back then he taught sailing at the local community college, a course that was very comprehensive and involved at least three days of sailing aboard his Catalina 30. When I got to the marina that first day, a trip of 22 miles, it was cold, drizzling and a bit windy. I was only a few yards from the slip when I put the boat in reverse and tried backing in--not a prayer. At best I would have wiped out three boats in the process. We motored out to the middle of the Susquehanna River, spent a few minutes getting the feel of the boat in reverse, and backed it into the slip just as if I had been doing it all my life. The difference was, IMO, the sailboat, for it's weight and displacement, is frequently under-powered. The engines, generally, are relatively small--just enough to get the boat away from the dock and cruise along at hull speed under ideal conditions. It doesn't have the awesome power of a powerboat that you can stop on a dime using just the prop thrust.
The boat I recently purchased and is still on the hard is a 33 Morgan Out Island, a craft that I've been searching for for more than 3 years. The reason I wanted this particular boat was not for speed. (6 knots would be considered an exceptional day aboard the 33 OI.) It wanted this boat for comfort and its live-aboard capabilities. Additionally, it has a full keel, which I've been told is best for spending time offshore. The very first thing I noticed when looking at Morgan OIs all along the U.S. east coast was how thick the keel was, and how little clearance there was between the prop and the surrounding keel/rudder assembly. I figured the turbulence factor alone would make the engine very inefficient in any direction. I guess I'll find out for sure in late April when the boat goes in the water.
Interestingly, there are several sailboats in the marina where my Catalina now lives that are powered with outboards. Some are on brackets that are situated well away from the keel. The outboard motor's cavitation plate is positioned an inch or two lower than the hull, thus there is no obstruction to propulsion in any direction. These guys merely lock their rudder in a neutral position and back the boat into the slip using nothing more than their outboard engine. Keep in mind that in order for an outboard engine to work, the cavitation plate MUST be below the hull. It the plate, which is just above the prop, is above the bottom of the hull, the prop will just sit there and spin and the boat will barely move. Kinda' like placing an electric fan in the cockpit of the sail boat on a windless day and blowing it on the sails--nothing happens.
I've looked at a couple web sites that discussed ways to improve this situation by modifying both the keel and rudder. For the life of my I've never understood the reasoning behind making a rudder with a nearly blunt leading edge. If we designed aircraft wings that way they wouldn't get off the ground. The same holds true for the trailing edge of a keel. It should be tapered to provide the least resistance to water flow. One site I looked showed how part of the keel could removed and tapered, which I believe would alleviate much of the problems associated with full keel boats and tight rudder assemblies.
Oh well, got to go to work so I can pay for the updates on the Morgan,