Nowadays, commercial ships, including ocean transportation, ocean fishing and scientific investigation, are large enough to store food and fresh water needed during the voyage. The bigger problem is only the problem of vegetables and fruits, because the characteristics of vegetables and fruits have not been preserved for a long time. In this case, the crew will find their own way, for example, when they go to the ocean, the chef will make their own bean sprouts. In addition, the ship doctor has all kinds of vitamin tablets, which can be requested. In fact, after a long time, the ship doctor will take the initiative to send them.

Then when we land, we will make up the food and fresh water we need.

Those personal adventures you mentioned are special cases. They just want to experience the life that they have nothing to live by themselves, so they try not to fish, catch seabirds, collect rainwater and so on. In fact, far from the coast, fish are easier to catch, and sometimes even bait is not used. In addition, although the seawater is salty, the juice on the fish is light. After catching the fish, remove the head and skin, and then squeeze it by hand, which will squeeze out some fish juice and save lives at critical times. But speaking of it, it's strange and fishy, but when it comes to saving lives, it's also nectar.

You might as well try. Don't complain. I didn't say it.