I also have a Nacra F18 and posed this question to Bob at the Performance Catamarans factory on a tour I took there a few months ago. He said that is ok to stand on the daggerboards when righting the boat. I believe he advised against any kind of bouncing.

I was asking the question from the perspective of a solo sailor since I often solo the boat. I did not ask him if 2 people could safely stand on the daggerboards when righting.

I am an even bigger gorilla than your friend. I weigh about 230 pounds, plus the weight of my wetsuit, harness, lifejacket, waterproof Ipod, and VHF radio, gets me up to about 240. I find that I am able to right the boat by myself when its on its side, but it is critical to have the mast pointing upwind, but slightly rotated from straight upwind so that the wind can come under the leading edge of the sail and help to lift the sail out of the water. The less wind, the less help you get. The technique if very similar to waterstarting when windsurfing: you use the wind to help lift you up through proper positioning. If I dont do this, and choose to ignore the angle of the mast & sail to the wind, the leverage of the weight of the water on top of the sail at the end of the mast is tough to overcome. Your friend may not have water in his mast. It might just be poor positioning. I do not normally stand on the daggerboards. Despite Bob's reassurances, I am uncomfortable with the concept and have found it is unnecessary for me and my mass. I have not tried to get right my boat from a turtled position.

As a backup, I do always carry a waterbag with a block and tackle. I did buy and install a Power Pole righting system and was less than excited about it. When it was not being used, it formed a lump in the center of my trampoline I could feel when tacking. The first time I tried to use it, the sheet metal screws used to secure it at its base came out. It is not longer on my boat.