I was sailing with a dingy sailing freind on a 30'' lwl 9 ton gaff rigged sloop coming into Portland Maine. The day was perfect, the sun was out, The wind was strong, 20-30 miles per hour, we were on a beam reach in protected water with no waves to speak of and sailing as fast as the boat will ever go. She had a bone in her teeth and a long wake spread out behind. I was loving it, my freind was terified that the boat was about to roll over...
It all perspective. To knock down the 34 footer will take either really bad seamanship or really bad weather. Do you plan to go sailing in gale force winds? If you do will you refuse to reef the sails? I won''t go any further because I think I have made the point. Don''t spend a lot of time worrying about knockdowns on a 34'' sailboat of the type your thinking of buying. Worry about weather, worry about becoming a competent sailor. If you do those two things you will probabley avoid knockdowns all together.