Dave Gerr - Boat Mechanical Systems Handbook-How to Design, Install, and Recognize Proper Systems in Boats

Propeller Shafts: Diameter, Bearing Spacing, and Bearings

Of course, the propeller shaft itself has to be

properly sized and supported. Too little diam-

eter causes shaft whip and vibration, while

too much diameter is waste. The simplest

and roughest rule of thumb is that the shaft

should be one-fourteenth the propeller diam-

eter. In fact, this is pretty close—so much so

Chapter 1: Propellers and Shafts

Figure 1-9. Pocket

or tunnel depth

Figure 1-10. V-section tunnel