Advantages of EALs Over ECLs
1. Environmental Accountability: EALs are backed by a clear definition and regulatory framework, making their environmental benefits more transparent and dependable.
2. Ecosystem Protection: EALs’s biodegradability and nonbioaccumulative properties contribute to the protection of aquatic ecosystems. Their use aligns with global efforts to reduce pollution and maintain biodiversity.
3. Regulatory Compliance: Mandatory usage of EALs in certain regions ensures that industries are actively contributing to environmental protection.
4. Enhanced Performance: EALs are developed to match or surpass the performance of conventional lubricants, dispelling the notion that eco-friendly options compromise functionality.
5. Innovation Incentive: Regulatory demands for EALs have spurred lubricant manufacturers to innovate and develop high-performing, sustainable products.
The Role of the Stern Tube
All types of vessels, whether container ships, bulk carriers, harbor tugs, or cruise liners, have one thing in common: propulsion is by means of large propellers of varying design. With few exceptions, the shafts of fixed-pitch and controllable-pitch propellers run in journal bearings mounted inside the stern tube filled with oil. The radial movements of the propeller shaft in the bearing are larger than those of other industrial shafts and may be intensified by the force of waves or vibrations.
Radial shaft seals or mechanical seals prevent the oil from leaking into the sea and keep the stern tube tight against the engine compartment. Thrusters are filled with gear oil and must be sealed at the propeller shaft as well as at the rotating steering shaft of azimuthing thrusters to prevent leakage into the water. It is, however, not possible to seal the stern tube or the thruster 100 percent tight against exiting oil.