Hi! Thanks for your dream.
Here's the most likely explanation for your recurring dreams, which I've taken from Michael Sheridan's dream interpretation dictionary:
"Saving people at sea usually indicates that you have the ability to rescue lost souls. This is an unusual gift and is used while your body sleeps. In actuality you can traverse the astral plane with ease. We all go there when asleep and souls who are crossing over after death can find themselves lost and confused. You, and others like you, specialize in finding them and helping them make their journey. You particularly use this when someone close to you dies. Apart from dreams of rescuing someone at sea, most people with this ability are blissfully unaware of it."
Hope that puts your mind at ease!

Olly