This is another part of the previous topic regarding the mainsail.We started a Saturday morning club 2 man race in Long Beach, Ca about 4 years ago. The wind was about 10 to 12 knots. We were 3rd off the line with the YC race boat behind us in 4th. Beating them off the line was the first win of the day. Unfortunately, it was also the last. Racing with middle to back of the pack racers as I do causes me to see the race as a series of events - start, 1st mark, 2nd mark etc. I evaluate how well we do in each event. That way I avoid having a totally bad day because we finished at the back of the pack.Anyway, we are about 1/2 way the first windward leg. The boat is a Newport30 (heavy clunky boat) with a 155. We are clipping along pretty good on port tack. Unfortunately, our view to starboard is obstructed by the deck sweeper 155. We both thought (big mistake) that no one was there. The next thing I see is the bow of the YC race coming across our bow. They are about 50' in front of us. We heard nothing as they approached but all hell was breaking out now. The Newport skipper was about 2 clicks behind me seeing the situation. After I get about 3 excited, unprintable words out of my mouth he catches up with the scene and throws the tiller over. All I was able to do was drop the traveler. I could not cut the jib sheet. We were trying to cut behind them but it was too late and we smash into the rear quarter of the YC club boat. What a mess as you could see right into the cabin.Obviously, the moral of this story is vigilence but another important lesson is the ability to stop or control a sailboat in the shortest distance possable. I almost think if I could have cut the jib sheet we might have made it. Maybe or maybe not.Another important point is marine insurance - the Newport skipper had none!! This is entireley stupid. We could have sunk the YC boat or injured their crew and us included. He worked it out with the YC but if it was an outsider he may not have been that lucky.