| Year | 1939 |
| Date | 06-Apr |
| Volume | 80 |
| Issue | 1,978 |
| Page | 396 |
| Category | Nautical |
| Part | |
| Title | Propeller Gearing |
| Author | "The Spectator" |
| Notes | Arrangement of four gears to drive twin screws, pattern with interior bored, the finished pattern, a boring jig, showing oil grooves in a shaft |