Offen Group has started installing scrubbers on nine 14,000-teu vessels this year.
The first was slated to be fitted at a Chinese shipyard last month, with the remainder retrofitted on a rolling four-week cycle.
Under a long-term charter deal, charterer Mediterranean Shipping Co (MSC) will reap all of the benefits of cheaper fuel. In return, the vessels will not be taken off-hire while being retrofitted.
