The report is indeed very interesting. As in many, if not in all, such disasters a combination of actions and failures produced this tragic outcome. The autopilot apparently failed b/c it had leaked hydraulic fluid sufficient to interfere with its function. This was not noticed possibly b/c it was not routinely being inspected. Several hours to minutes prior to complete failure the autopilot was evidently having some difficulty holding course. This may not have been known to the crew due the subtleness of it. However, there was NO WATCH posted at the helm. This alone is a bizarre failure of good skippering, IMHO.
The preventer failed in part due to the crew’s modification of the rigging as installed w/o due recognition of their insertion of a “weak link.” Also, due in part that a certain critical pad eye, mistakenly undersized, had been installed during a refit. Rigging the preventer had not been practiced b/f leaving port. It was an ad hoc modification done at the time of rigging it at sea. Apparently, the skipper did not supervise and could not describe to interviewers how it had been modified.
It evidently took a couple of slams of the boom (i.e., 2 or 3 uncontrolled jibes across the cockpit) b/f the traveler failed from shock loading (i.e., broke free of its track). Up until then it might have been possible to get control of the yacht even in the high wind and confused seas by disengaging the autopilot, heading the yacht up or perhaps by completing a jibe, bringing the yacht hove-to (?), then sheeting in the boom, etc. But—-NO WATCH at the helm at the onset!!
Once the traveler broke up it was really goodbye Charlie. The boom kept jibeing uncontrollably, slamming into the swept-back spreaders until the rig came down, etc. Tragically, two crew members where killed. One was knocked off, no life jacket on, and not recovered. The other was hit in the head by the traveler apparatus attached to the end of the boom which acted as “wreaking ball” according to crew accounts, and died of the injury.
A very thorough report which highlights how simple “oversights” and even common, though not entirely sound, practices can add up to BIG problems. Remember, a gigantic rogue wave, as often called, is really a bunch of smaller waves whose amplitudes coincide, additively, for some few minutes.