Since December 2013, the EPA’s Vessel General Permit (VGP) regulations on Environmentally Acceptable Lubricants (EALs) have been impacting owners of tugs, dredges, carriers and docks. Nearly two years later, it’s worth seeing how the change is being implemented.
For stern tube and propeller shaft applications, all of the major stern tube system manufacturers have now approved at least one EAL for use. That gives operators several options to handle the oil-to-sea interface in a stern tube, based on the economics of the situation:
- The seal material can be changed during the vessel’s next dry-dock to an EAL compatible material (e.g., EAL compatible elastomer lip seal rings). EAL options include base oils consisting of ester, polyalkyleneglycol or PAO/ester formulations.
- Other options include changing to an air seal or changing the shaft bearings to a water lubricated system, which eliminate the possibility of an oil discharge.
For tunnel thrusters and z-drives, several manufacturers have approved at least one EAL gear oil. Again, ester, polyalkyleneglycol or PAO/ester formulations as the base oil are good EAL options.
Fixed and controllable pitch propellers may use either a hydraulic fluid or a gear oil to lubricate and power the propeller blades, shaft and hub mechanism of a CPP system. As with thrusters, seal compatibility is the main concern for both new and existing equipment. For fixed pitch propellers, operators can use an approved EAL to fill the propeller cap void space.
Rudder systems require an EAL grease, unless a greaseless bearing is used. Several EAL greases have been approved by system manufacturers.
General deck and wire rope grease applications require an EAL if the application is intended to be immersed in water. Dredges and mooring lines with wire leads are examples of where an EAL grease should be utilized.
Hydraulic systems for deck/dock cranes, winches and hatch covers are not required to convert to EALs. However, some companies have chosen to convert to EALs due to other oil pollution regulations. Discharges of any oil that cause a sheen, film or emulsion into U.S. waters are a reportable offense. However, because using an EAL can reduce the impact on the environment, fines and cleanup costs will likely be less when the discharge involves an EAL.