Having a daughter about the same age as the girl who survived, I am very touched by this story. These 2 articles seem to put together enough pertinent information to get some understanding of what happened and the emotions that the girl must have felt.
It sounds like her father was essentially trapped in his lifeline and harness by the rigging as the water repeatedly washed over the entire boat. Mercifully, one could hope that he was already gone by the time they could cut him from the trap. It sounds like the rigging could have been killing him or holding him under water until he drowned. It also sounds like they realized as they were cutting him loose that they had no chance of rescuing him, and that the only hope was that he could somehow rescue himself if he was still alive.
What was really compelling to me is the way she described how she lacked the desire to survive at first and then somehow found the strength - attributing it to her father. This is a heartbreaking story and I feel for the survivors.