How Thordon delivered a record-breaking bearing in three days
By Jack Burke19 September 2022
It’s not a new material but Thordon Bearing’s SXL polymer material has gone big time. Really big time.
The Canadian company recently supplied the largest rudder bearing it has ever manufactured — 1230 mm long, 1111 mm diameter — for a 7506TEU containership. The bearing is made from the SXL material, which is designed to be self-lubricating and offer superior resistance to shock loading and vibration, said Scott Groves, the company’s vice president of sales.
The 2001-built vessel, operated by a European owner, was retrofitted with the Thordon bearing after the vessel’s original bronze rudder bearing required replacement due to excessive wear.
“You have a material that’s flexible enough to dampen vibration, to take impact, to resist ‘pounding out,’ so it’s not malleable and won’t suffer from plastic deformation,” Groves said, noting that the material is seven times lighter than metals.
Speed of the essence
The ship was undergoing its scheduled special survey and it was discovered the rudder bearing was “borderline,” Groves said.
“The opportunity was there to say: ‘If we can get this bearing in time, we can replace this bearing and make 100% sure that this thing is going to be bulletproof for a minimum of two special surveys, or 10 years.’”
Thordon’s SXL material has a lower modulus of elasticity than other non-metallic bearings, resulting in significantly increased vibration dampening, accommodation of edge loading and better impact resistance. The material has been used with almost 4500 rudder bearing applications. But this wasn’t an ordinary replacement.
Groves credits Thordon’s authorized distributor in the U.A.E. – Ocean Power International (OPI) – for making the project possible. OPI was contacted by DryDocks World (DDW) shipyard to put forward an alternative rudder bearing solution, with OPI recommending Thordon’s grease-free SXL polymer bearing.
From receiving the order, it took just three days to manufacture, ship, deliver, machine and fit the record-breaking bearing using liquid nitrogen during the 12-day drydocking.
“If you were going to have that casting done in a piece of bronze, you would have had the issues with raw material supply, you would have had the issue of scheduling that into a foundry and naturally the cost of freight – that may not have fit on the Emirates A380 (airliner), which is what flew ours to Dubai.”
It was key to have a trusted partner like OPI on scene for the project to succeed, Grove said. OPI is in Dubai and serves the Middle East market. “Once something like this leaves the factory, the infrastructure has to be in place at the receiving end to make sure it is installed correctly,” Grove said. “That’s where the partnership with the distributor comes in.”
OPI had the machine shops to make sure measurements, such as those for the bearing bore and pintle shaft, are made correctly. OPI also machined and fitted the new bearing, which is a cast product and made only in one facility in Canada, Groves said. It takes roughly 24 hours to cure before it can leave the building.
“Ocean Power International is considered an essential service provider to the U.A.E.’s maritime industry, so we do get priority clearance on equipment headed to Dubai Drydocks,” said Rafid Qureshi, managing director of OPI. “DDW couldn’t believe it was manufactured, shipped and delivered in just three days. The CEO called me personally to thank us for the quick turnaround.”
Thordon Bearing prides itself on being able to adjust quickly to special orders and the demands of customers. “The company has grown over the years and regardless of our size, we always keep some capacity back to handle daily rush requirements,” Grove said. “That’s the nature of the marine business. If you don’t have the capacity to react to these types of things, you’re in the wrong business.
“The manufacturing team here absolutely embraced that opportunity,” he said. “That’s a fairly unique type of casting job for us. It was the biggest, and it doesn’t get any more unique than that.”
A longtime product
The polymer material isn’t a new product for Thordon Bearings, which is part of the Thompson-Gordon Group, a family-owned company established in 1911. When it first came to the market in the 1960s, the crosslink polymer alloys were mostly used in industrial operations, including scale pit pumps in steel mills.
“From there, the next logical step was to look at the ship industry, and local ship owners were the first to give Thordon Bearings a try in rudder bearing applications,” Groves said.
Back in the early days, showing this to customers was “a bit of a stretch” because it’s quite different from traditional materials, mostly bronze, Groves said.
“Why would people traditionally use metals? For the same reasons people use traditional materials in other applications – that’s just the way it is,” Groves said. “Bronze…is the industry standard, so if you’re dealing with a ship superintendent, they may say it’s not their preferred choice, but it works. And it does.”
But Thordon Bearings argues its products offer important advantages in the marine market, including the fact they’re grease-free. That means there’s no exposure to environmental risk through the use of grease. And if greased products are used, you’re likely to get particles trapped in the grease eventually, turning the grease into a lapping compound, Grove said.
“Because of the flexibility and elasticity [of polymer], you have a significant amount of abrasion resistance compared to bronze,” he said. “Bronze is quite soft, actually, and if you get something abrasive in there, it’s going to gouge the material out.”
The lubricant is built into the polymer material matrix during the casting process. As the material wears, the coefficient of friction won’t change because the lubricant is throughout the material.
Another key consideration is environmental regulations regarding oil and grease discharge.
“It’s becoming much, much, much, much more stringent,” Grove said of environmental standards in the marine market. “Regardless of what the future environmental regulations are, going with a grease-free solution is future proofing it.”
He noted, too, that since the bearings are self-lubricating, that mean’s there’s one less touchpoint, lessening safety concerns. Eliminating grease also cuts costs and frees up some space onboard.
“Since there is no longer a requirement to grease our bearings, the associated labor, cost and pollution source is removed,” Grove said. “Internal lubricants formulated into the material reduce friction, resulting in smoother, longer lasting, grease-free bearing operation.”
On a new install, Thordon offers a 15-year Rudder Bearing Wear Life Guarantee, which covers the provision of a replacement if the bearing wears out and requires renewal within 15 years of installation. If it’s in a retrofit situation, the company matches the warranty of the material that was replaced, up to 10 years.
OPI is also currently working with DDW on various projects to replace containership fairleads with Thordon’s grease-free ThorPlas-Blue bearings.