Sailors mostly wouldn't fish out in the open ocean because of a lack of fish. For a better answer I would like to refer to an answer that redditor backgrinder had written for the question "Why didn't ship crews fish when lost?"

"This misconception is based on a common mistake made by people who haven't spent much time on the water: that fish are freely available and easy to catch everywhere because hey: ocean! The ocean is full of fish the way the land is full of humans, which is to say there are quite a lot of them but they are very unevenly distributed. Most people think of the ocean as teeming with fish but this is because most people's experience with the ocean is very close to shorelines, and shorelines are hot spots for fish populations just like they are hot spots for human populations, and for the same reason, the easy availability of food."

So if they were close to land they could fish.

Catching rain to use as drinkable water would be something that sailors practiced because it was a valuable and efficient way to top off fresh water. Sails would be used to catch rainwater from storms and showers.

I found this article that says that sailors did fish during the trip. It mentioned water in passing as a less-preferred beverage, but nothing about collecting rainwater.