Scrubber retrofit

A scrubber retrofit installs an exhaust gas cleaning system on an existing ship so it can continue burning high-sulfur residual fuel while complying with the MARPOL Annex VI 0.50 percent global sulfur cap in force since 1 January 2020. The work routes the main engine and often the auxiliary and boiler uptakes through the scrubber tower, adds wash-water treatment and monitoring, and carries significant weight high in the funnel that the stability book must absorb. The payback depends on the price spread between high- and low-sulfur fuel.