If they didn't keep her partner alive, the movie would sink to the level of All is Lost.apparently they took a few liberties with the original story:
On Oct. 12, shortly after Sharp told her to go below deck to rest, Ashcraft heard Sharp scream and was knocked unconscious as she was thrown against the cabin wall when the boat capsized. When she regained consciousness a day later, the storm was over. Scrambling above deck, she discovered Sharp's safety line dangling over the end of the boat, but he was gone. Ashcraft surmises the waves and wind were so powerful that Sharp was jerked out of his safety tether and swept overboard. The cabin was half-filled with water; everything in it was smashed or scattered on the floor. The masts were broken off and the waterlogged sails floated uselessly in the water. The engine, radio, electronic navigation system and emergency position-indicating radio device were broken.
Alone, terrified, injured with a bad cut on her head, and grieving for her fiance, Ashcraft nonetheless managed to rig a makeshift sail from a broken spinnaker pole and an extra storm jib and pump the water out of the cabin. Navigating manually using just a sextant and watch, and surviving on peanut butter and canned food, she sailed 1,500 miles in 41 days to reach safety in Hilo, Hawai