Bailer

A Hand Bailer is a device used for removing water which has entered a boat. In the simplest case, it is merely a container which can be filled manually and then emptied. This kind of device is in use since early times. It is still in use on small boats and rafts. Some regulations require them as mandatory equipment.

Iron Age hand bailer from Nydam Mose

Norwegian "auskjer", traditional hand bailer

modern plastic hand bailer

For some modern types of dinghys in sailing sports hand bailers can be obsolete when they are equipped with self bailers, sometimes also called automatic bailers.

self bailer, rear type

self bailer, bottom type outside the boat

self bailer, bottom type inside the boat

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Wikipedia