An ocean of noise could be greatly reduced if more ship owners opted for noise-free marine bearings.
This is according to Vesconite Bearings, which is promoting its bearings materials as ones that exhibit low squeal, vibration and noise because of their low friction, small clearances, and no slip stick.
Vesconite bearing materials have an unusually low coefficient of friction so there is little squeal when using Vesconite since:
• Vesconite has a coefficient of friction of 0.12 – 0.15 running dry on stainless steel;
• Vesconite Hilube has a coefficient of friction of 0.08 – 0.12 running dry on stainless steel; and
• Vesconite Superlube has a coefficient of friction of 0.05 – 0.08 running dry on stainless steel
In addition, the materials exhibit little to no slip stick, the jerky motion associated with sound that is common in applications with intermittent motion. This is because Vesconite Hilube and Vesconite Superlube, in particular, have excellent stiction characteristics, since their coefficients of static friction are lower than their coefficients of dynamic friction … and this results in less noise or no noise at the start of motion and during slow rotations.
Moreover, because Vesconite does not swell or distort, Vesconite bearings can be machined with small clearances. This considerably reduces vibration and associated noise, since there is much less play between the bearing and its housing.
These bearing characteristics are important in an ocean environment in which noise levels are believed to have doubled every decade since the 1950s. This has largely been due to the increase in shipping and is also contributed to by small boat traffic in coastal waters.
Depending on the species, and the noise frequency and intensity, various physiological conditions have been noted in animals, including increases in blood pressure, heart rates, cortisol levels, cholesterol levels and respiratory rates.
For marine animals, besides physiological disturbances, there may be behavioral responses to avoid noise, including ascents that are too rapid and spending too much time on the surface.
These factors make the choice of bearing important for those who are concerned with the environmental impact of human activities in marine environments.