Please select your home edition
Edition
A+T Instruments 2024 Leaderboard

New evidence suggests synthetic EALs are behind increase in stern tube seal failures

by Thordon Bearings 28 Nov 2023 07:21 PST

Seawater-lubricated bearings pioneer Thordon Bearings has welcomed the publication of Gard's latest research into the potential hidden costs of synthetic Environmentally Acceptable Lubricants (EALs).

Far-reaching financial and environmental consequences can result when a propeller shaft seal failure occurs, with the Norway-headquartered marine insurance firm pointing to a "significant increase" in propeller shaft aft seal damage following the 2013 introduction by the US EPA of new Vessel General Permit (VGP) rules.

According to Gard, the increase in the number of seal failures directly correlates with the increase in the use of approved synthetic lubricants - these lubricants are among those in compliance with US EPA regulations.

Gard's research, published in October 2023, has taken a deep dive into the data around the shaftline damage claims it has processed over the last 10 years. Its research shows that as many as 80% of the incidents Gard investigated involved stern tube seal failures where an EAL was in use.

Thordon Bearings' VP of Business Development, Craig Carter, said: "It appears that the introduction of a synthetic EAL as a means of mitigating the risk of mineral oil pollution has had unforeseen consequences. Seawater alone is the only 100% pollution-free means of lubricating a ship's propeller shaft bearing."

Gard's research has suggested that one reason for the seal failure hike (and consequent increase in insurance claims) is based on the chemical composition of synthetic EALs, which, while being environmentally preferable to the mineral oils that are being phased out, are typically inferior in performance.

Gard cites a 2019 study by DNV which discovered that two key features of EALs set them apart from the traditional mineral oils widely used before 2013: viscosity and pressure coefficient.

Under high load operations, such as hard turns at high speeds, EALs can operate with a lower safety margin of the minimum oil film between the propeller shaft and the bearings. Secondly, EALs typically operate with lower viscosity under lower temperatures, in situations like mooring trials and cold start-up.

Touched on by Gard, there have also been countless reports in the international trade press suggesting that the increased incidences of discarded fishing nets or rope are adding to the aft seal damage of oil-lubricated shaftlines.

"This research from Gard underscores our own findings that the most environmentally acceptable lubricant is seawater as was recommended by the US EPA in the Vessel General Permit (VGP)" said Carter.

"Thordon's COMPAC bearings are at the heart of our award-winning open seawater-lubricated propeller shaft bearing system, which means zero oil pollution into the marine environment. And let's not forget any oil leak, big or small, can be catastrophic to the marine environment and marine life, with some EALs found to be only slightly less damaging than the phased-out traditional oils."

The Thordon COMPAC system eliminates the need for the aft seal, as well as offering reduced friction, hence diminishing fuel burn and main engine emissions. This proven shaftline design also provides improved bearing wear life, predictability and reliability while offering lower maintenance costs, easier installation, and future-proof compliance.

To read the Gard report in full, please visit www.gard.no/web/articles?documentId=36102314

Related Articles

Excess launched the 100th hull of the Excess 14
Behind this hull #100 are more than 70 passionate staff who have put their expertise to work A symbolic milestone for a model that embodies our vision of the catamaran: sharp design, easily gliding through the water, and pleasure at the helm. Posted today at 8:22 pm
2025 USVI Charter Yacht Show set for November
A rising tide of opportunities for boat crews and brokers A rising tide of opportunities for boat crews and brokers to connect, from one-on-one meet-and-greets to USVI-style social events, is what makes the 2025 USVI Charter Yacht Show a 'must-attend' industry event. Posted on 28 Jun
NMMA Canada hosts successful 2025 Day on the Hill
Building momentum for repeal of luxury tax NMMA Canada wrapped another highly successful Day on the Hill in Ottawa this month, bringing together industry leaders, government officials, and policymakers to advance priorities critical to Canada's recreational boating sector. Posted on 26 Jun
NTG Global Graduate Program
Shape your career and propel yourself into the world of innovation North Technology Group, a global leader in advanced composite technology, is offering an exciting and dynamic graduate program that will shape your career and propel you into the world of innovation. Posted on 26 Jun
Axopar Boats expands US dealership network
Together with OneWater Marine Axopar Boats Ltd., the market leader and originator of Adventure motorboats, is strategically expanding its presence in the US together with OneWater Marine Inc, one of the biggest marine retailers in the United States. Posted on 26 Jun
Despite world politics industry remains resolute
A summary of news relevant to marine businesses across North America As part of NMMA's continued advocacy efforts following the 2025 American Boating Congress (ABC), a group of NMMA leaders visited Capitol Hill last week to meet with Congressman Mike Collins (GA-10). Posted on 25 Jun
Superyacht Mast Servicing in Asia
MC1 Service leads the way As the superyacht industry continues to expand across Asia, the need for specialised rigging and mast servicing has never been greater. Posted on 25 Jun
Vision Marine acquires Nautical Ventures Group
A Florida-based recreational boat dealership, marina, and service provider Vision Marine Technologies Inc. (NASDAQ: VMAR) ("Vision Marine" or the "Company") announced the acquisition of Nautical Ventures Group, Inc. ("Nautical Ventures"), a Florida-based recreational boat dealership, marina, and service provider. Posted on 23 Jun
Garmin unveils flagship Apollo RA800 marine stereo
Advanced stereo features a reimagined internal amplifier, faster processing, high-resolution audio Garmin (NYSE: GRMN), the world's largest and most innovative marine electronics manufacturer, has announced the premium Fusion Apollo™ RA800 marine stereo that brings reimagined design and powerful audio performance to boaters everywhere. Posted on 20 Jun
NMMA members meet with Rep. Mike Collins
A group of NMMA leaders visited Capitol Hill last week As part of NMMA's continued advocacy efforts following the 2025 American Boating Congress (ABC), a group of NMMA leaders visited Capitol Hill last week to meet with Congressman Mike Collins (GA-10). Posted on 19 Jun
Selden 2020 - FOOTERCyclops Marine 2023 November - FOOTERNorth Sails Loft 57 Podcast