I just changed boats this year from an O'Day 25 to a Douglas 32. In addition to the full keel, extra 8000 lbs and left hand prop with an inboard diesel, we have switched from a mooring to a slip at our local marina. To say that we have had some challenges coming and going would be an understatement, as I need to reverse and turn to starboard to leave, and my boat does not want to do that ever. I provide this information to say that I am not an expert, but am cautious when coming and going.Anyway, we have been struggling but getting by - but while I was on the boat today doing some maintenance and upgrades (most of the day) I did witness a powerboat collide with another powerboat on leaving the dock (he actually tried to leave at full power with a spring line still tied), as well as a sailboat collide full speed in reverse with another sailboat returning to the marina. Once the shock wore off, I got to thinking that this must be a fairly common occurance. I have seen lots of high speed approaches with a big thrust of reverse at the last minute, and this seems reckless to me. Do these things happen at other marinas? Why don't people ask for assistance rather than risk damaging their own - and others - property? I am beginning to reconsider the safety of remaining where I am now, given what I've seen over the last few weeks. Maybe a row of fenders over the stern would help?