Page 32: of Maritime Reporter Magazine (February 2024)

REPAIR

Photo Courtesy Marine and Industrial Transmissions ings to optimize load distribution.

A large number of the incidents analyzed by

Gard were attributed to ghost ? shing gear that enter the stern tube seal area causing seawater to contaminate the lubrication oil. A 2022 study by CSIRO scientists estimated that the amount of longline ? shing gear littering the ocean each year can circle the Earth more than 18 times.

Additionally, 14 billion longline hooks litter the sea each year, but this too could be a de- clining problem. Huge as they are, the research- ers found lower levels of ? shing gear losses in this study than in a previous study published in 2019 – potentially the result of better weather forecasts and improved marking and tracking of ? shing gear.

President Bob Shortridge says Lignum Vi- tae’s water-lubricated stern tube bearings stand out for its longevity and shock resistance. The company places a strong emphasis on address- ing the issue of high bearing wear, particularly in slow sailing vessels. In pursuit of optimal performance, Lignum Vitae is engaged in engi- neering tests in collaboration with Hydro Tech

Removing the stern tube bearings.

in Canada. These tests are focused on modeling bearing performance under different loads and speeds, enabling customization of clearance and of the propeller in combination with hydrodynamic propeller loads in certain operating conditions can lead to aft end edge pitch angles. This approach deviates from the one-size-? ts-all loading. The most critical parameter for ensuring that doesn’t method commonly observed with other bearings and has led happen is to slope the bearings to better match the slope of the to dramatically reduced bearing replacement time in drydock.

Unsurprisingly, seawater-lubricated bearings pioneer Thor- shaft. A good bearing design is important.” DNV’s November don Bearings welcomed the publication of Gard’s data. “Let’s 2023 guidance suggested the use of double-sloped aft bear-

A Thordon Bearings stern tube- less ship concept.

Photo Courtesy Thordon Bearings 32 Maritime Reporter & Engineering News • February 2024

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