MarQuip said it created a marine exhaust system that combines the principles of selective catalytic reduction, which eliminates nitrogen oxide compounds, with highly efficient noise reduction.
The Dutch exhaust manufacturer is working with an Italian boatyard to develop the custom module silencer/SCR system, which is compliant with International Maritime Organization Tier III emissions standards and reportedly reduces sound levels by 35 db(A).
The silencer/SCR module is integrated into MarQuip’s water-injection side of a system that also features underwater exhaust. The exhaust manufacturer said the first challenge was to stay within the maximum back pressure specified by the engine manufacturer.
This can be complicated because adding after-treatment equipment to exhaust systems can increase back pressure. A specially designed underwater scoop helped reduce it.
Noise reduction was the second step, and MarQuip said it combined the high-frequency capabilities of the SCR unit with dedicated low- and medium-frequency components.
The final step was to marinize the SCR module. MarQuip said it knew from experience that pressure pulses in waves of up to 500 mbar in heavy weather cause equipment failure, so its engineers designed the unit to withstand up to 600 pressure pulses.
Production of the new silencer/SCR system has begun. It is slated for delivery in September.