Project Description

DIVING STATUS uses always Rubert Scale comparator in order to confirm the quality of the propeller roughness.


The presence of even immature barnacles or tubeworms on the propeller causes a severe loss in propulsion efficiency. The technical solution on this problem is removing all calcium deposits and any basal plates with propeller polishing. Propeller polishing should be carried out to maintain the propeller surface roughness at or near-equal to Rubert scale A.

In service, regular underwater cleaning and reconditioning of the surface of a propeller is done with a small rotating disk that can easily conform to the complex shapes of the blades without gouging the surface. This tool removes all fouling and produces a very fine surface scratch pattern in the range of 1 to 2 μm. This is similar to what would be expected of a newly manufactured blade surface. Any large nicks or damage, especially to the leading edges or tips, should also be repaired and smoothed out.

To easily assess the condition of the surface it is common to use a comparison guide like RUBERT SCALE SHIP PROPELLERS ROUGHNESS GAUGE that provides actual surface roughness examples for visual and tactile comparison. The specimens are labeled A to F, with A and B representing expectations for the roughness after polishing.

Necessary equipment:

  • Polishers
  • Handheld brushes
  • Abrasive & Diamond Discs
  • Rubert scale comparator (Ship Propeller Roughness Scale)

Materials of Cleaning Discs:

  • Diamond
  • Silicon Carbide
  • Aluminum oxide

The bristle size, abrasive grit and matrix and density of the fiber can make these discs more or less aggressive.


  • Our purpose is to remove fouling and provide a smooth surface.
  • Extreme care must be taken to retain the proper contour of the 3-inch area adjacent to the propulsor leading edges, trailing edges and tips.
  • Localized fouling concentrations should be spot-cleaned
  • The personnel shall be familiar with the critical areas and areas of high curvature geometry.
  • Positive control of the equipment to prevent tool motors, housings and controls from contacting the propulsors surface