Longitude Engineering is ready to support its customers with their efforts to reduce harmful emissions from ships. With the 2020 Sulphur cap to limit emissions of oxides of Sulphur (SOx) approaching, all ships are affected. Additional requirements exist for the limitation of emissions of oxides of Nitrogen (NOx) and particulate matter (PM), although the latest of these are aimed at new tonnage, when operating in special areas.


The options available for reduction of SOx are, at a high level, either remove the Sulphur before the fuel is burned or afterwards. The cost of low Sulphur fuel oil is relatively high and marine gas oil is even higher when compared to residual fuel oil. Longitude can assist with the decisions on which approach to take, based on the economics of installation of flue gas desulphurisation technology versus operating with low sulphur fuel.

The reduction of NOx is generally carried out using one of two methods – exhaust gas recirculation (EGR) or selective catalytic reduction (SCR). Both methods are often available from the manufacturer of the engine to which they are connected and are also supplied as retro-fit solutions. Longitude has carried out engineering design for the installation of SCR plants on vessels fitted with medium speed Diesel engine power plants, as shown in the design model generated by Longitude for a conversion project with an installed power of 8MW.

Exhaust systems

Longitude are experienced with working on ship’s exhaust systems. From the basic requirements to go into an outline specification, through to detailed design for installation. Shown here are a single line diagram for a newbuild design with a 12MW plant as well as a finite element geometry model of part of a 20MW plant’s system, generated to solve noise and vibration issues experienced.

Design engineering

Retro-fit work is always balanced against the capital expenditure required and the off-hire time spent during the installation. Longitude have a number of partner organisations we work with to carry out the 3D scanning of machinery spaces prior to docking periods. With the right amount of planning and engineering design, retro-fit projects can be completed on time and on budget, as Longitude most recently demonstrated with two ballast water treatment plant installations. These were installed by a UK shipyard to the integration design drawings Longitude delivered.