Seafarers of yore had no maps, GPS, or satellites to warn them of hazards that lay ahead.
To give sufficient notice of danger, the ship’s lad would be sent to the crows nest, and a neutered male sheep would be thrown overboard to swim ahead of the ship. If the sheep came upon a reef, it would stop swimming, stand up, and look back to the ship in the hope of being picked up. The first person to notice it would be the lad aloft. Upon seeing the whether eye, the lad would shout to the helmsman to adjust course to avoid the reef.
When hurricanes struck, another neutered male sheep would be cast overboard, tethered to the stern. The drag of the sheep would keep the ship facing head on to oncoming seas, and the vessel would whether the storm.