- Changes in EPA requirements for Environmentally Acceptable Lubricant (EAL) are impacting applications for stern tube and propeller shafts, tunnel thrusters and z-drives, propellers, rudders and more commercial vessel uses.
- Even where not required for deck/dock hydraulic applications, some companies are converting to EAL to limit oil pollution liability.
In December of 2013, the U.S. Environmental Protection Agency (EPA) implemented the revised Vessel General Permit (VGP). This revision requires carriers, tugs, dredges and other commercial vessels operating in US waters to use Environmentally Acceptable Lubricants (EALs) in certain oil-to-sea interfaces. It affects all commercial vessels greater than 79 feet, operating as a means of transportation and calling on U.S. ports. It sets standards for minimizing the discharge through a combination of best practices, required actions, and equipment upgrades.
Required lubricant usage
Section 2.2.9 of the VGP details the requirements for lubricant usage for oil to sea interfaces including wire rope and mechanical equipment subject to immersion. The requirements apply to any thru-hull fitting or propulsion system with an oil-to-sea separation seal. The current status of implementation depends on the equipment and application being lubricated, the availability of approved lubricants, and the approval of the equipment manufacturer. When no EAL products are approved for use in a given application that meet manufacturers’ specifications for that equipment, the operator can wait until the approval is issued. In these situations, a letter of infeasibility should be issued from the manufacturer of the equipment. In addition, products which come pre-lubricated (e.g., wire ropes) and are not available with EALs can be continued to be ordered. However, this applies to the purchase of the product and may not cover the re-lubrication of the application. If products meeting a manufacturer’s specifications are not available within any port in which the vessel calls, the transition can be delayed. Lastly, the changeover and use of an EAL can wait until the vessel’s next dry-docking if the conversion can only be completed during this time. Generally, applications that do not require an OEM approval or a dry-dock period should already have been transitioned.
For stern tube and propeller shaft applications, operators have several options for compliance. All of the major stern tube system manufacturers have now approved at least one EAL for use. The seal material used can be changed during the vessel’s next dry-dock to an EAL compatible material (e.g. EAL compatible elastomer lip seal rings). EALs are available with base oils consisting of ester, polyalkyleneglycol or PAO/ester formulations. Operators should consult with their lubricant supplier and system manufacturer to determine the correct EAL for their operation. There are two options available that eliminate the oil-to-sea interface in a stern tube.
- An air seal system can be installed to separate the lubricating oil from the outside water. This type of system has been conditionally approved by the EPA.
- The other option is to change the shaft bearings to a water lubricated system. The decision on which solution to use should be based on the economics of your operation.
For tunnel thrusters and z-drives a gear oil is required and equipment manufacturers are beginning to approve EALs for use. Several of the top z-drive and tunnel thruster manufactures have approved at least one EAL for new orders. For a vessel currently under construction, the vessel owner should verify that the thruster was built with EAL-approved seals. For thruster systems already in use, manufacturers are requesting notification in advance of a dry-dock to allow for review of maintenance schedules and availability of upgrade packages.
Fixed and controllable pitch propellers are another application for EALs. Depending on the design, either a hydraulic fluid or a gear oil is used to lubricate and power the propeller blades, shaft and hub mechanism of a CPP system. Some major equipment manufacturers have approved EALs for this application while others are still in the test phase. As with thrusters, seal compatibility is the main concern for both new and existing equipment. For fixed pitch propellers, operators should transition to the use of an EAL approved by the equipment manufacturer to fill the propeller cap void space.
Rudder systems require an EAL grease unless a greaseless bearing is used. Several system manufacturers have now approved EAL greases for this purpose.
General deck and Wire Rope grease applications should be converted over to an EAL if the application is intended to be immersed in water. In particular, dredges should be investigating the different greases available to determine which provide the best value for their operation. Mooring lines with wire leads are another example where an EAL should be utilized.
Hydraulic systems for deck/dock cranes, winches and hatch covers are not required by the VGP to convert to EALs. However, some companies have chosen to convert these applications to EALs due to other oil pollution regulations. Discharges of any oil that cause a sheen, film or emulsion into US waters is a reportable offense. However, because using an EAL can reduce the impact on the environment, fines and clean-up cost will likely be less when the discharge involves an EAL.
The Vessel General Permit has an annual reporting requirement for each vessel (or group of vessels) to document their status of EAL conversion. The reports for the first year (December 2013 through December 2014) were required to be submitted by the end of February 2015. The EPA is now assessing the reports to determine the status of implementation and gauge the effectiveness of the transition.