Adrift in the Pacific(1982)

Juugo Shounen Hyouryuuki

Fifteen young students embark on the boat that should lead them to their families on the coasts of New Zealand. Unfortunately the boat loses its anchor and heads to the open sea in the middle of the night without sailors on it. In the morning, a violent storm prevents the children from sailing back to the harbor. A few days later boat grounds on a deserted island in the Pacific ocean. During 20 months the fifteen children will be left alone and will have to get organized in order to survive. they manage to store up food for the cold winter that will be soon there. Briant, Doniphan, and Gordon lead the group of children who find out that a sailor has lived and died on the island 20 years before.

(Source: Anime News Network)