I had my boat (PC34 Hull68) pulled for the winter two weeks ago and had my yard block her for the off season. Upon my inspection of her yesterday, I found two groups of small cracks in the floor liner just forward of the port engine compatment. Upon further investigation, I found out the boat needs to be blocked in a "specific way" to prevent any hull flex or stress. My boat was not blocked correctly. This info of placement does not exist in the MV34 Manual as far as I can see. I'll share what was told to me by PDQ. Three supports are needed on each hull. The forward blocks should be located under the bulkhead area just aft of the generator compartment. The mid-ship blocks should be located under the bulkhead enterance into the cabin berths (under the door area), and the aft supports should be located at the stern behind the rudder. (I am sure it's a bit different in the other sail cats) I am told these hull can flex quite a bit but the interior liners are less forgiving. I am hopefull the hull is not damaged as no visible cracks are evident but I 'll have a little bit of glass reapir to do in the spring. Just wanted to share my experience with you folks and check your blocking this winter. (I know you Southern boaters are just gloating in the warmth and sunshine.... 
) But you northerners, check your supports....
Sandy Kramer
MISHIGAS PC34