daf bit: Kiddushin 29

[cellio]

Some commandments are binding on men but not on women, among them the following obligations to his son: to circumcise him, to redeem him, to teach him torah, to find him a wife, and to teach him a craft. Some say: and to teach him to swim. Rabbi Yehudah said that a man who does not teach his son a craft teaches him brigandry. (29a)

Comments

[cellio]

On the serious side, even though bodies of water are dangerous, they are also pleasurable, and a fantastic natural resource. Without the ability to swim, one loses a substantial amount of the utility of the water.

That's an important point. The safest reaction to something potentially dangerous is to stay away, but that's not what the rabbis call for. Balance is important, and pleasure is worth a small risk.