The West Marine 275 HP weight is about 50 lbs the larger 310 is closer to 60 lbs. Even with our bad backs, we can get these dinghies easily on the top of the C Dory (although I now have a Davit hoist) what we have done, is I go foreward, and Marie is aft on the side deck. I bring the bow up with the painter. Marie has one hand on the cabin top railing, and then grabs the boat as low as she can by the life line on the side of the inflatable. As she pulls up, I grab the boat even lower than she has it, and usually we can easily just stand the boat up on its "tail" and slide it up over the cabin top athwartships. Then we spin it around, turn it over or what ever we want to do with it. Granted we don't have a radar arch. I would think that the radar arch would give you a better hand hold. If you are queezy about standing on the narrow side decks, then I could see a problem. We pedistal mount the radar, and the inflatable will fit over it upside down. No problem with the inflatable extending over the front or back of the cabin top. We lash the inflatable in place using the hand rails. Launching is a one person event--just slide the boat over, tie the painter to the top railing with enough slack and ease the boat into the water. At times we deflate the boat and carry it on top (including when towing behind the truck). We have never felt that the 50 or so lbs has been a problem with stability. Often the radar arches, and radar domes etc equal this much weight.