Broad Carbon LTD produces and supplies brushes for propeller shaft grounding on ocean going vessels around the world.

Propeller shaft bearings are vulnerable to corrosion.
This is because turning shafts are electrically insulated from the hull by the lubricating oil in the bearings and by the use of non-metallic bearings in the tail shaft.
The problem is eliminated when the propeller shaft is grounded to the hull structure using a shaft slip ring.