I have never had the little plastic disc that is on the boom crack, but the holder that attaches to it has. I have replace at least two rod holders because of this. The stress was greatest on the port side as the pressure was causing the holder to separate where it meets the part on the boom, as much as 1/8th of an inch. On the starboard side the rod holder is forced into the boom and the bottom have did not separate away from the section on the boom. I have since turned the port boom 180º so that the rod holder is now on the fwd side of the boom. Essentially now the same as the starboard. I replaced the boom extension retaining nut with a lock nut so that the locking bolt would not vibrate out, as it is now on the bottom of the boom.