The five-year window to September 2024 in which to carry out retrofit of a BWMS will see installations peak in 2022 but not all the existing fleet will make it past this milestone.

As retrofit capacity becomes tighter, projections indicate there will likely be a bottleneck of ships seeking installations, resulting in a peak of potential removals.

This phenomenon can be attributed in part to the decision by IMO in MEPC.297(72), adopted 13 April 2018 and effective 13 October 2019, to de-harmonize IOPP certificate renewals from the BWM Convention compliance process.

On a global basis, ABS estimates that approximately 45,000 vessels of 2,000 dwt and larger have yet to adopt BWMS for compliance. On average it expects that approximately 25% of these vessels will not likely complete their fourth Special Survey at 20 years and would not be retrofitted with a BWMS.


Even so, approximately 30,000 vessels of 2,000 dwt and larger will have BWMS retrofits during their Special Surveys (coincident with IOPP certificate renewal surveys) between September 2019 and September 2024, taking into account that some will need to install a USCG-approved BWMS before their IMO regulation B-3 (as amended) dates.

This works out to about 500 retrofits per calendar month. Based on the man-hours of work required to add these retrofits to the normal out-of-service periods (engineering/designers, BWMS manufacturers, class, flag, shipyards and owners) the industry will likely need a lot of additional technically qualified personnel to accomplish this work by the deadline. If any of these stakeholders have not yet ramped up to meet these challenges, the entire five-year implementation plan would be at risk of failure.

Retrofit challenges include fitting the BWMS itself (footprint, dry and wet/operating weights affecting structures) and increased power demand, often challenging the vessel’s existing electric generator capacities. Coincident with some earlier BWMS retrofits will be 1 Jan 2020 SOx regulations/exhaust gas cleaning systems (scrubber) installations.

Scrubbers have significant power demand and water pumping requirements that can exceed the vessel’s current power generation capacity. Replacing auxiliary engines requires compliance considerations with progressive NOx regulatory Tiers that would add to the costs for the vessel’s compliance and could make relatively newer vessels no longer economically viable post-retrofit.

ABS recommends proper and early BWMS technology choices, selecting experienced designers (with early experience on retrofits), proper BWMS vendor selections based on market staying power, technical assistance and service level, and effective operator training will be new predictors of performance for retrofit vessels. Getting any of those wrong can doom a vessel to the scrapyards.


The views presented hereabove are only those of the author and not necessarily those of  SAFETY4SEA and are for information sharing and discussion  purposes only.

About William Burroughs 

William Burroughs is a Senior Principal Engineer at ABS responsible for promoting environmental related services and providing guidance in support of international, national and regional marine environmental regulations.

Bill’s previous experience includes Product Line Manager for the BALPURE® BWMS manufactured by De Nora Water Technologies and serving his country as a Lieutenant in the United States Navy’s submarine force. He has 33 years of experience in engineering and project management. He earned a bachelor’s degree in Chemical Engineering from Auburn University and has extensive experience in the fields of chemical, electrical, mechanical and nuclear engineering.

He is also a Chartered Engineer and Chartered Marine Engineer of The Institute of Marine Engineering, Science and Technology and member of the IMarEST Ballast Water Experts Group