Sponsored by Imtra

Better Boating Technology

Modern thruster and stabilizers transform the handling and performance of older yachts.

February 23, 2017
imtra side power
Many yacht owners are discovering the advantages of proportional control as they upgrade from older systems. Imtra

The new technology and fresh designs of the Side-Power systems deliver improved maneuverability, greater comfort, and superb performance.

Twenty years ago, bow thrusters were wish-list options. Now, they’re standard equipment on most new motor and sail boats. The refit market has also seen gains in thruster installations, mainly from owners upgrading older one-speed thrusters to new proportional control models.

Side-Power, which designs and builds about 160 thruster options, has been making marine equipment since 1908. Its thrusters have been market-share leaders for years. “Side-Power has been making proportionately controlled DC thrusters for a long time,” says Prentice Weathers, a Side-Power specialist at Imtra, the U.S. distributor of its thrusters and stabilizers. “But refitting a proportional thruster to older on/off systems is a relatively new trend among boat owners.”


Many yacht owners are discovering the advantages of proportional control as they upgrade from older systems. “Proportional gives you full control of the thruster’s speed as opposed to on-off, which offers full speed or nothing,” says Weathers. “The proportional thrusters tend to have much longer run times. They’re also much quieter.”

Imtra helps owners find the right-sized thruster through drawings of their motoryachts and sailboats. “We calculate how much force the thruster needs to overcome the wind on the boat,” says Weathers. “Side-Power rates thrusters by how many pounds of thrust they produce so it’s a straightforward equation to match the boat with the right thruster.”

“Bow thruster installation usually involves through-hull cuts, requiring tools and expertise that many DIYers may not have,” notes Weathers. “We can help in the refit to proportional. The owner sends us his motor (no need to haul the boat), we recondition it and return it with the proportional controller and other components. This upgrade also starts a new 2-year warranty on the motor. But we also recommend working with companies specializing in thruster installation.”


Within its wide range of DC, AC and hydraulic thruster options, Side-Power has also designed thrusters for different niche boats which work well for refits. The Side-Power EX series, for instance, is a pod where the motor and thruster are enclosed in an external package. “It’s ideal for boats such as catamarans or houseboats where you don’t have room for a tunnel 5 to 10 inches below the waterline,” says Weathers.

Side-Power’s SX series is a stern thruster for boats with dual outdrives where conventional stern thrusters would not work. The company also makes retractable thrusters for sailboats. Weathers says that Side-Power’s position as a market leader isn’t just because of its wide product range. “It’s because they’re so good at what they do,” he says. “They’ve grown by virtue of their quality and excellent support network worldwide, of which Imtra is a proud member.”

For higher speed yachts, the Vector Fins™ create lift. Improving overall speed and fuel efficiency compared to straight fins. Imtra

Side-Power has also grown with other products like its Vector Fin™ stabilizers. Imtra has worked with many yacht owners who have refitted their vessels with Vector Fins. The curved stabilizers have been proven to be up to 50 percent more efficient than standard fins in reducing roll at anchor, and 30 percent more effective under way.


Most owners, says Weathers, notice the difference immediately. “They see big gains in many directions,” he says.

“The curved shape directs the stabilization force more vertically than a straight fin, so it counteracts roll force more efficiently,” notes Weathers. “The curved shape also reduces the negative side effects of yaw and sway. The greater efficiency allows the Side-Power fins to be smaller than straight fins, too.” For higher speed yachts, the Vector Fins™ create lift. Improving overall speed and fuel efficiency compared to straight fins.

Another feature that sets the Vector Fins™ apart are the much smaller size of the actuators. “They take up less space and don’t intrude into the living space like others do,” says Weathers. “That’s particularly important for the refit market since actuators are often positioned in the main stateroom. Side-Powers are also virtually silent—another significant advantage over its competitors’.”


Of course, the ultimate refit is getting a thruster and stabilizer combination from Side-Power. The systems connect through S-Link and can work with other on-board systems. “Side-Power’s proportional joystick systems integrate seamlessly with modern engine joystick systems from Volvo, Xenta, Twin-Disc, ZF, Glendinning and others,” notes Weathers. “Side-Power provides a plug-and-play gateway to integrate with all major systems. That’s just another feature that shows the sophistication of their systems.” At last technology seen in larger yachts and commercial vessels is now available to all. Zero Speed stabilization, Dynamic Positioning and station holding, and precise vessel control can all be retrofitted.

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