As pressure has mounted to reduce underwater radiated noise (URN), a new technology that drastically cuts propeller noise has been invented.
The new technology is from a collaboration between Oscar Propulsion Limited and the University of Strathclyde.
The new invention called PressurePores places a few small holes at the tips of each propeller blade. These allow water to pass through the blade by relieving the pressure on the blade. This reduced pressure results in radically decreased propeller tip vortex cavitation, which reduces underwater radiated noise. The new invention has been shown to reduce cavitation by 14% and sound by up to 10Db.
According to Oscar Propulsion Marine Director Lars Eikeland:
“Underwater radiated noise is one of the most adverse environmental by-products from commercial shipping, yet unlike other forms of marine pollution, there is currently no international legislation in place to prevent or reduce this source of environmental damage…Increasing noise levels, especially in the low-frequency range, is disorientating marine fauna and disrupting their communication signals, leading to behavioral changes or extinction. We now have a cost-effective, easy-to-apply solution that prevents this from happening.”
“It’s not a case of simply drilling holes into the blades, as this will affect the propeller’s thrust capability. We know exactly where to place the holes for maximum efficiency and for optimum noise reduction. We have found the optimum number of holes required to reduce the noise. So long as the right number of holes are placed in the most effective positions, a cavitation sweet spot can be achieved.”
You can check out a video of the effects of noise below.