Commercial marine industry professionals met virtually to discuss practical solutions to meet the fleet decarbonisation regulations that are coming thick and fast from January 2021.

The second session of the Commercial Marine Network’s five session Decarbonisation conference, sponsored by Southerly Designs, was based around the subject area of refitting the fleet. 250 delegates were registered for the event.

Following the usual introductions from Moderator Kerrie Forster of the Workboat Association and Chairman Andy Page of Chartwell Marine, Andy Osborne of the Port of London Authority got the ball rolling with some real world experience of integrating the regulations in a very mixed fleet of vessels.

The PLA runs a fleet of 30 powered craft, some of which are decades old, and the organisation has taken on some quite serious targets for itself, quite apart from the overarching legislation. Most notable of these is to reduce its annual carbon output by 60% (from 2014 figures) by 2025.

There is also an air quality strategy and a tight decarbonization roadmap that have been implemented. While some of this will call for repowers, Andy was quick to point out that many of the vessels simply do not have room in their engine compartments for the Tier III solutions with their bulkier aftertreatment components. There’s clearly also not budget available to replace the fleet. So there has been a large exercise at the PLA of seeing what options are available from the manufacturers, for each vessel and which vessels will require more temporary workarounds. Andy was quick to point out that especially for the smaller vessels, Teir III engines that could fairly directly replace the existing engines, in some cases, were impossible to find from any manufacturer.

Cedric Merveillaud, the Europe Sales Director of Cummins Marine was on hand to fight the corner of one of the manufacturers at least. Of the various aftertreatment options to meet the Teir III NOx limits, Cummins has gone for SCR (Selective Catalytic Reduction). It’s a low back pressure system that Cummins are happy to supply a two-year warranty with. One sobering fact that Cedric provided was that the reduction in NOx between Tiers II and III is 70%, so no surprise that the reworking of products has been a major job for all the manufacturers. The gaps in what new engines are available versus the PLA’s new engine wish list, began to make sense, as Cedric pointed out that for certain engine families the business case was just not yet there for introducing a Tier III variant.

Cedric provided two interesting Cummins-powered case studies; a Norwegian hybrid ferry and a series hybrid food delivery catamaran in the USA, both of which were already demonstrating significant benefits to their operators.

Owen Preece of Bureau Veritas clarified matters on what the new rules are and when they are coming in with a useful timeline from where we are now all the way through to 2050. BV’s also had to do some fast work to keep up with the changes, and Owen was able to share three new vessel notations that the classification society has introduced: ELECTRIC HYBRID, BATTERY SYSTEM and ULEV (Ultra Low Emission Vessel).

Back on the original subject of repowering existing vessels, Owen clarified the rules. A repower is usually considered, as far as the IMO rules are concerned, the same as a new vessel. Ie., any keel laid after January 2021 needs Teir III power. But for older vessels there is one workaround, in that an exact like-for-like engine replacement does not count for this. The problem will increasingly be finding exact replacements for engines for older vessels where the engine might no longer be in manufacture, but for older fleets, it could be a temporary option to keep boats working. A similar workaround solution is to rebuild engines instead of replacing, and in older workboat fleets there is going to be plenty of that going on in the next few years.

Don’t miss the next sessions in the Commercial Marine Network’s decarbonization webinar series in the new year, when we will be stepping ahead into the 2030s where drop in fuels, repowering with cleaner diesels and rebuilding engines will no longer be realistic options.

Missed this webinar or any of the others? Watch them (free of charge) at

By Jake Frith