I am a firm believer in a back up engine of some type and have always had some back up propulsion system. I have not lost a diesel which I have not been able to fix in short order. However I have lost transmissions twice. I also have had props disabled by floatsum. I have a friend who has a 55 foot trawler with a 150 main and a 50 hp wing engine. This engine has a controlable pitch prop and is used on a regular basis--as well maintaned as the main. My feeling is that a get home engine should have a separate shaft and prop--and maybe even a flanking rudder for that engine. I would want it to have another function--such as powering the watermaker, refer/freezer compressors , large DC generator etc, so that it was run on a regular basis. Perhaps my view is colored by having towed a number of boats which had failed main propulsion systems. Yes, most of these were fuel or electrical related and should have been prevented. One can say--just anchor or sea anchor and fix the problem. Probably in 90% of the time, this would be possiable. There are those other few percent which could be critical for a passagemaker. Of course if there is an adequate sailing rig...I might change my mind. Regards, Bob Austin