Every ship has a permanent hole below the waterline, and without it, the propeller couldn’t turn. This opening, known as the stern tube, is one of the most critical and dangerous parts of a vessel. Discover how engineers use seals, bearings, lubrication, and clever physics to keep the ocean out, what happens when the system fails, and why a small problem here can leave a massive ship stranded at sea. ⚓

Source: How Does the Stern Tube Work?