If you want to be safe, don't go sailing. I've always thought of a motor as a convenience item. Sure they're great to have, but as Tom says, you can certainly get around without one. You may not have the same access to certain areas as someone with a motor but it's a stretch to say it's a safety item. Now if you are set on using an inflatable then you pretty much need a motor. I wouldn't want to row an inflatable more than a few yards.