The Ballast Water Management Convention (BWMC) of the International Maritime Organisation (IMO) will take effect in September 2017 and it may drive some of the oldest cruise ships out of business due to cost of compliance.

The Convention requires owners of existing vessels to fit equipment that will prevent the spread of organisms with ballast water discharges at the first dry docking of each vessel after Convention has taken effect.

Speakers at the annual conference of the International Chamber of Shipping in London last month said that the equipment will cost between $0.5 million and $5 million, depending on the size of the installation.

At the end of May 2016, there were eight cruise vessels built in the 1960s still in service, which had a combined capacity of 4,232 lower berths. Cruise vessels built in the 1970s numbered 14 and their combined capacity was 8,512 lower berths. The global cruise ship fleet had a combined capacity of 506,356 lower berths at the same point in time, according to figures in Global Ocean Cruise Market Analysis & Forecast by Odo Maritime Research.

Should all the ships built in those two decades leave the market, it would not have a material impact on the supply of cruise berths. However, it might lead to some companies finding it difficult to find suitable replacements to the aged tonnage due to be taken out of service.