Impala Zambrano, the first of 15 triple-screw and twin-screw pusher boats scheduled for oil-to-water conversion, was retrofitted in July 2015 with a RiverTough bearing and TG100 shaft seal combination.
Three triple-screw and one twin-screw pusher vessels have since been converted and Thordon’s Colombian distributor Delta Marine and River Services will now work on the next vessels in the series. All 15 tug/towboats are scheduled for conversion by the end of 2017.
The low level of water in Colombia’s waterways, an effect of the drought caused by El Niño, is a major concern for Latin American owners of workboats operating on the region’s rivers.
Jorge Luis Vélez, Manager, Delta Marine and River Services, said: “By far the biggest problem with the original oil-lubricated system was the small 4mm (0.157-in.) clearance between the propeller and Kort nozzles. When silt or sand lodged between them, it prevented the circulation of lubricating oil, resulting in increased friction and high bearing temperatures. Ultimately it was destroying the bronze bearing, potentially causing catastrophic damage to the shaft.
The success of that first conversion resulted in Impala Terminals Colombia contracting Delta Marine and River Services for RiverTough/TG100 retrofits to a further fourteen Magdalena-operating vessels.
Andy Edwards, Commercial Director, Thordon Bearings, added: “We hear operators with traditional oil-lubricated bearing systems having to replace them every two years or so due to excessive wear, which is completely unnecessary. Data from vessels operating Thordon’s RiverTough bearings show typical wear rates of 0.075mm to 0.100mm (0.003 to 0.004-in.) in 6000 to 7000 hours of annual use. They routinely outlast rubber bearings by a factor of two or more.”
Delta Marine has begun retrofitting RiverTough bearings and TG100 seals to the remaining vessels, each of which will require bearings and seals for shaft diameters ranging from 165mm (6.5-in.) to 186mm (7.3-in.).