The blade's leading edge enters the water first, while its face, back, trailing edge, fillet, hub, and boss describe the surfaces that transmit force and connect it to the shaft. Behind the propeller, bearings and the stern tube support the rotating shaft where it passes through the hull. Seals make that opening controllable rather than perfectly dry, because some leakage becomes more likely as a ship and its fittings age. A Royal Navy carrier example shows how a wrongly specified seal can cause trouble even on a new ship, while fitting the correct part can resolve it quickly. Correct specification, inspection, and replacement of those seals are essential parts of propulsion reliability.
Chapter · 13:14-15:39
Propeller anatomy, shaft bearings, and stern-tube seals
A compact terminology guide connects blade faces and edges to the shaft, bearings, stern tube, and seals that control seawater leakage through the hull.