Propeller Roughness (shown at left, front & back)

Specimens A & B are replicas of the surface roughness of new or reconditioned propeller blades to be used as a standard for comparison with similar surface roughness taken from propellers eroded by periods of service, since propeller efficiency deteriorates in time due to the increasing surface roughness and also with the growth of marine fouling.  Specimens C, D, E, & F can be used to assess and report upon the propeller blade surface condition after periods of service.  Propellers in service should be examined frequently and any fouling removed as soon as it is noticed. After cleaning, the surface condition should be checked using the comparator and the roughness recorded.  The propeller should be repolished if the roughness exceeds the maximum allowable amount in the figure shown at left.

• Designed for measuring the roughness of propellers
• Underwater -- a must for any company offering propeller polishing services.
• Consists of a pocket-sized reference scale with 6 specimens resembling various stage of propeller roughness, plus a waterproof table for recording readings underwater by diver.

Recognized worldwide by the shipping industry for propeller inspection and repair.

Required by ABS (American Bureau of Shipping), Lloyds of London, US Navy, and other class societies worldwide, for the determination of the condition and serviceability of ship's propeller.