BOATS & GEAR
THRUSTERS
— newbuilds or major conversions — have picked up on the technology since then. “There are definitely applications for the Z-drive and L-drive on longline vessels, even factory trawlers,” says Schottel’s West Coast Account Manager Ingi Huswick. “There are a lot of advantages. When you get to these larger vessels, one of the more complex things can be the long, complex shaft line that’s a maintenance headache, and it’s also going through your tankage and taking up space. With the Z-drive or L-drive, you have options for installation where you don’t have to build around the
“Our equipment maximizes efficiency.” — Ingi Huswick, Schottel
shaft line.” Huswick explains that both Z-drive and L-drive are azimuth thrusters — able to rotate 360 degrees — the Z-drive requires two gearboxes, one up at the motor and one down in the propeller, while the L-drive the motor is mounted on top of the propeller
Product Spotlight Solid and powerful, Wesmar thrusters work
W
ashington state-based Wesmar has been turning out solid, reliable, and powerful bow and stern
thrusters for the commercial fishing industry for more than 55 years. Bryan Thiemann, Wesmar’s account sales manager for the United States, said the company’s longevity and reliability have made their products ubiquitous across the nation’s fisheries. Wesmar
“If it’s a commercial fishing boat, it potentially has our stuff on it,” Thiemann said. Part of Wesmar’s success comes from their unique design, Thiemann added. Each Wesmar thruster has two counter-rotating four-
Dual props increase thrust and efficiency.
blade Kaplan propellers. The dual-prop system raises efficiency by splitting power between two different gear sets, and the wash from the forward propeller is picked up by the aft, creating greater thrust. Wesmar bow and stern thrusters run from 5- to 500-horsepower, and the efficient dual propellers add up to more thrust per horsepower unit. This means space savings on smaller boats. “For instance, with the Bristol Bay gillnetters, which is a big market for us, they’re often very shallow-draft vessels, so they don’t have a ton of space for a bow thruster. The Wesmar allows them more thrust in a smaller profile tunnel,” Thiemann said. Gillnetters, Thiemann said, typically use thrusters with 8-inch propellers, but Wesmar offers 12 sizes running all the way up to 48-inch propellers, covering a wide range of boats across many fisheries. Solid stainless construction has been another key to Wesmar’s presence in the fishing industry. “All of our thrusters, bow and stern, are full stainless steel construction. It’s 305 cast. We have stainless housings, gears, bearings, props. Everything we do is commercial duty… and manufactured in the USA. We’ve been doing it since 1965, and we make quality products that are built to last,” Thiemann said. Thiemann noted that thrusters that are 25 or 30 years old often come into Wesmar’s shop in Arlington, Wash., and need just a simple seal and O-ring service to get back on the water. According to Wesmar, they use “the highest quality seals to the input and output shafts to prevent water ingress and oil leakage.” Service on the seals is simple because the thrusters do not have to be taken apart to swap out seals. Wesmar’s two-bolt drop-in design makes retrofits simple for metric tunnels, with a couple models that can easily replace Max Power, Side Power, and Vetus thrusters. All Wesmar thrusters can be run on hydraulic power or a choice of DC 12-, 24-, or 48-volt power or AC variable speed.
44 National Fisherman \ Spring 2022
— Brian Hagenbuch
and eliminates the need for the upper gear box. “Our equipment maximizes efficiency,” says Huswick. “Eliminating the rudders, for example. Even when the rudder is turned a little, you start losing propulsion because you’re pushing against it. You can lose up to 30 percent efficiency when it’s turned hard.” The system also gains efficiency in the way it manages power. “There’s also a lot of redundancy in the system,” Huswick says. “With all those generator sets, you can run both drives with one or two, and the failure rate on an electric motor is much lower than on your typical diesel engine.” According to Huswick, the system utilizes a load share module to shift loads between engines, enabling each engine to run at maximum efficiency. “I may shut down some engines, or shift power where it’s needed,” he says. Maintenance on the rudder propellers used on the Northern Leader is vital. Failure of the seals would wreak havoc on the units. “We did our five-year ABS overall on it after six years of service,” says Huswick. “We replaced all the seals and bearings. It only took a day or two, but those technicians don’t www.nationalfisherman.com
