there are several threads on here that address righting a catamaran - there is certainly a technique to it. Briefly however, there are a couple of things you need to do.

1) make sure your mast is sealed! If you are getting water in your mast while the boat is capsized...even a little...it will make righting very difficult. To check, submerge the whole mast in the water (while it's off the boat) and look for bubbles. Seal any leaks.

2) uncleat the mainsheet and the jib.

3) you must orient the boat into the wind and use the sails to your advantage. With the boat capsized, put your weight on the bow and you'll see the boat start to spin as the bows drag in the water (sometimes standing on the stern works too). You actually want to get the boat to the point that the wind is blowing into the "V" formed by the top decks of the hulls and the mast - you probably will not be able to get the mast to point into the wind. With the righting line already in place, quickly move back to the righting line and lean out.

3) As the boat starts to come up, you will notice that the sails will catch the wind and make righting much easier. Be prepared to grab the dolphin striker as the boat gets right side up. You want to hang on to keep the boat from rolling right back over to the other side. Once the boat is up, quickly get back on board before it could start to accelerate (it's unlikely - but possible if the sails are not released completely).

I weigh(ed) 170lbs and I've been able to right my 400lb F18 catamaran on three occasions by myself.