Thordon Bearings’ authorised distributor in Mexico, TZ Industrias, has secured an order to supply the Canadian company’s TG100 shaft seals, equipped with a safe return to port (SRTP) emergency seal, to a quartet of shrimpers operated by Pesquera Axel, one of the country’s leading fishing vessel operators.
Bearings and seals
TZ Industrias will deliver four 127mm (5in) diameter mechanical seals to the Mazatlán-based repair yard Constructora y Reparadora de Buques for installation in June to the 7m (23ft) long fishing vessels Kukulkan, Chavito, Chavito 2 and Judilily.
The scope of supply also includes Thordon’s seawater lubricated SXL tail shaft bearings and grease-free ThorPlas-Blue bearings, of which the latter will be installed to each of the vessels’ rudders and winches.
TG100 tail shaft seal
We became very interested in Thordon’s TG100 tail shaft seal when we heard about its safe return to port function"
Edgar Perez, Managing Director, Pesquera Axel, said, “We became very interested in Thordon’s TG100 tail shaft seal when we heard about its safe return to port function. With a fleet of 72 fishing vessels operating in some difficult marine environments, the safety of our crew and vessels is of the utmost importance.”
Arturo Selvas, Managing Director, TZ Industrias, said, “Fishing vessel and crew safety is very important in Mazatlán right now. There have been several incidents where Mazatlán-based fishing vessels have taken on water or sank. In April, for instance, a tuna fishing vessel sank, and in April 2021 a shrimp boat collided with a ferry off Topolobampo, Sinaloa.”
Reliability and maintainability
Arturo Selvas continues, “Fishing vessel operators want a seal with an emergency function capable of preventing water ingress, but they also want a seal that’s reliable, effective, and low maintenance. The TG100 is widely seen as offering a greater level of redundancy while delivering greater reliability and maintainability compared to other mechanical seals on the market.”
Pesquera Axel, a new customer for Thordon Bearings, has joined a growing number of fishing companies to have converted their vessels’ tail shaft seals and bearings to Thordon’s environmentally safe alternative. In 2021, TZ Industrias and Thordon began converting all the shrimp vessels in the Pesca Industrial Maros fleet to TG100.
Thordon TG100 emergency seal
Changing to a Thordon TG100 emergency seal is the optimum solution for vessel safety"
Jason Perry, Thordon’s Regional Manager for North America, said, “This latest order underpins the increasing interest for Thordon technology among the fisheries of Mazatlán.”
“Changing to a Thordon TG100 emergency seal is the optimum solution for vessel safety. It has an excellent performance record with hundreds of units now in service. It is an important component to vessel safety, protecting not only the lives of the crew but also the vessel.”
Approval in Principle
Thordon Bearings has welcomed the announcement by classification society ABS to award Approval in Principle to the “stern tube-less ship” concept developed in cooperation with the Shanghai Merchant Ship Design & Research Institute (SDARI), the National Technical University of Athens (NTUA), and Thordon Bearings Inc.
The revolutionary design replaces a vessel’s stern tube with an irregularly shaped chamber that allows a shorter, water-lubricated propeller shaft to be inspected and maintained while the vessel is afloat, without having to withdraw the shaft in drydock.
Cost savings
The design is likely to save shipowners hundreds of thousands of dollars in capital and operational expenditure
While the concept eliminates the need for oil-lubricated stern tube seals and bearings, a major source of marine pollution, the design is likely to save shipowners hundreds of thousands of dollars in capital and operational expenditure over a vessel’s lifespan.
Speaking ahead of an ABS-organized seminar in Athens during the Posidonia trade fair, Anthony Hamilton, Technical Director, Thordon Bearings, said the concept “revolutionises the ships’ traditional sealed propeller shaft”.
Vessel design
Anthony Hamilton adds, “We started wondering why a vessel with a water-lubricated shaft line needs a stern tube. Why couldn’t the shaft simply run in the larger space outside the stern tube?”
“This space is designed into virtually all vessels where an oil-lubricated stern tube is traditionally exposed to seawater for cooling. With a water-lubricated shaft, this space still exists but it’s wasted space.”
Sterntube-less ship
A stern tube-less ship features a shorter shaft with the prime mover further aft the vessel
Hamilton said the space could be used to access the shaft for inspections, and a lot of the shaft installation and operational challenges “completely disappear”.
A stern tube-less ship features a shorter shaft with the prime mover further aft the vessel. An additional bulkhead seal and a torsional vibration damper would be required but there is no aft seal and Thordon’s COMPAC seawater lubricated bearing replaces the oil-lubricated bearing aft.
Freeing more space
“ABS and the Technical University of Athens have done the math and the engineering behind it. They’ve looked at system pressures, temperatures, loads, noise and vibration levels, shaft alignment everything works,” said Hamilton.
Craig Carter, Thordon Bearings’ VP of Business Development, said, “There are huge savings here. You would never have to withdraw the shaft again, which can cost $100,000 in drydocking costs alone. We are not changing the design of the ship or the stern but by moving the engine further aft we free up more space for cargo.”
Virtual tour
Dr. Chris Leontopoulos, Director of Global Ship Systems Center, ABS Athens, said, “The use of seawater to lubricate the propeller shaft is well-established but the proposed design takes this further by removing the stern tube, decreasing the shaft line length, reducing engine room space and increasing the cargo space. It enables significant efficiencies and cost savings for operators.”
Thordon Bearings is taking shipowners, shipbuilders, repairers, and members of the maritime press on a virtual tour of a stern tube-less ship on the Thordon (Technava) booth 3.111, during the Posidonia trade show, which takes place in Athens, Greece.
