Home | Contact ST  
Follow ST


2018:  JAN | FEB | MARCH

Going Beyond Polar Code Compliance

Craig Carter,
Director of Marketing and Customer Service,
Thordon Bearings

The International Code for Ships Operating in Polar Waters, or the International Maritime Organization (IMO) Polar Code, entered into force January 1, 2017 for ships built after that date. It covers all safety and structural aspects relevant to navigation in waters surrounding the poles—including pollution prevention. The Polar Code prohibits the discharge into Arctic waters of any oil, oily mixture or noxious substance. It will apply to all ships from January 2018.

The introduction of the IMO Polar Code will lessen shipping’s impact on the sensitive Arctic and Antarctic ecosystems, but, unfortunately, it doesn’t go as far as regulating against or eliminating the use of oils and grease in deck machinery, which can, of course, leak into the oceans. To be ever vigilant against polar pollution, shipowners should consider any system that can negate the use of oil or grease completely without detriment to the performance of machinery.

Although some oils and greases are considered biodegradable, many have difficulty degrading in environments where sunlight is limited or temperatures are extreme. Biodegradable oils also harm birds, as they are attracted to the oil, which can cover their feathers and cause hypothermia, leading to birds freezing to death. So, any shipowners operating in the harsh polar environments need to consider the type of lubricants and greases they use.

Another issue to keep in mind is ensuring that deck machinery—davits, fairleads and winches, cables, etc.—is maintained to provide optimum performance and safety when temperatures fall below -10° C (14° F). Not only can lubricant viscosity be severely affected, potentially resulting in the failure of critical equipment, but further challenges arise since deck machinery requires frequent greasing by crew members. Certainly, the length of time crew members will be able to spend on deck in the harsh polar environments to carry out regular maintenance and greasing will be limited, which could have serious consequences on the performance of deck machinery, especially those using conventional bronze or metallic bearings.

Polymer bearings are a great alternative to conventional bronze bearings; for example, thermoplastic deck machinery bearings are completely maintenance and grease-free. These bearings use a tough polymer matrix to ensure a low, stable coefficient of friction, even as the bearing wears. Wear rates are very low compared to greased bronze, ensuring long life and dramatically reduced maintenance costs.

Polymer bearings can operate in temperatures down to -50° C (-58° F) in dry conditions and -10° C (14° F) in water. There is no need for grease as they are completely self-lubricating. Performance is also unrivalled where high operating pressures up to 45 MPa (6,527 psi) are encountered, and these bearings can be simply retrofitted in all deck machinery applications where greased bronze bearings are typically used.

For the expedition-type cruise ship, where being seen to be clean and green is sacrosanct, we are witnessing increased interest in thermoplastic polymer bearings since they prevent blobs of grease from streaking down the sides of an otherwise pristine ship into the surrounding marine environment.

For any shipowner looking to operate in Arctic or Antarctic waters, the importance of environmental protection cannot be underplayed. And while environmental protection often comes with a price tag, since additional or new equipment is required, considerable savings can be achieved from green technologies.

While polymer technology does mean a slightly higher capital investment than a traditional bearing system, operational costs associated with the purchase, storage, application and disposal of oils and greases are eliminated, providing shipowners with a swift return on the investment. Nonbudgeted expenditures resulting from bearing seizure, such as replacing expensive rope or cables, are also minimized. These savings benefit the shipowner, while the technology helps protect the harsh and fragile polar regions.

-back to top-

Sea Technology is read worldwide in more than 110 countries by management, engineers, scientists and technical personnel working in industry, government and educational research institutions. Readers are involved with oceanographic research, fisheries management, offshore oil and gas exploration and production, undersea defense including antisubmarine warfare, ocean mining and commercial diving.