This is another version of the story "Walking Shadows" by Alfred Noyes which was done a bit better as "The Log of the Evening Star" on Escape. A lot of good dialog in this one and none too slow but they pissed away the big shock with a filtered "ghost voice"... The simple revelation of the captain alone in his cabin, speaking as though to his wife - as seen by the last survivor - would have worked better. Then they beat us over the head with the point several times (Yes, his wife is dead. She was dead before the voyage. Yes, we got that...) before the captain follows her.
Still looking for a few really good episodes. 