I can't remember if the protagonist was a man or a woman, but I think it was a man.
He was on a planet (mostly?) covered in water where people carried out research on floating stations. Each station had only a couple of people working on it and they kept in touch by regular transmissions.
Some kind of disaster struck, and he had to travel to another station, and then perhaps on again to another, trying to find survivors or reach a way off the planet. I think he has an engine and a raft for some of it and ends up paddling a lot.
He's having an affair with one of the other researchers, or at least he thinks about his spouse who is off-planet when he is scared of dying. He ended up either traveling with or wistfully thinking about traveling with his other partner.
It's slow-paced for a story where someone's fleeing for their life.
It would have been medium-long, maybe 30 pages, and I read it in a short-story collection like "Best SF nn" so it's likely to have been written between 1950 and 1985.