By using two propellers that rotate in opposite directions, a ship can use less energy to move forward.
By using two propellers that rotate in opposite directions, a ship can use less energy to move forward. New knowledge means that more ships can use the technology, including Hurtigruten’s Sea Zero project for its coastal cruise ships.
SINTEF has now designed and manufactured new measuring equipment for model testing of contra-rotating propellers. This could be good news for many large ships.
“We see that propulsion efficiency increases when we utilize some of the energy lost from the front propeller at the same time as the rear propeller gets better water flow. This can provide more than ten percent better efficiency compared to conventional propellers,” says Øyvind Rabliås, a researcher at SINTEF.
Although contra-rotating propellers are not new, they are still rarely used on commercial ships. The reason has been their cost and more complicated design than traditional layouts. That may be changing now.
Read More: Norwegian University of Science and Technology
Image: One of the setups investigated in the Sea Zero project was a combination of contra-rotating propellers (the red propellers in the middle of the picture) and two pulling thrusters. A pulling thruster acts as a propeller that pulls the ship forward, much like an aircraft propeller. Photo Credit: Brunvoll
