A water-cooled exhaust system enables compact installation and flexible positioning of the exhaust outlet, including mounting in or through the hull — both above and below the waterline, depending on the design and sailing characteristics. As a result, a chimney or funnel is no longer always necessary, which provides completely unobstructed visibility from the bridge, especially on workboats, patrol vessels, and fast aluminium boats.

Because the exhaust gases are cooled back drastically, they rise less quickly and smoke nuisance on deck is noticeably reduced. This increases the comfort and safety of crew and passengers, especially when a vessel is manoeuvring or lying still and cannot sail out of its own smoke screen. In addition, some of the soot particles are washed out with the water, reducing contamination on deck and equipment. These properties make water-cooled systems particularly suitable for modern, functionally designed vessels.

A water-cooled exhaust system operates under challenging conditions in which hot exhaust gas, water, and fluctuating loads continuously affect one another. In salt water, salt crystal formation can occur, remaining behind in the system as a hard deposit and increasing back pressure. In fresh water, limescale is more likely to form, causing similar problems.

Over many years, Discom has transformed the practical experience it has gained into detailed knowledge of material behavior, enabling us to know exactly which alloys, wall thicknesses, and systemic measures are reliable in specific sailing areas. In doing so, we do not only look at the official sailing profile; in practice, a so-called “freshwater system” regularly still comes into contact with seawater. Through our attention to system design, injected water behavior, and controlled discharge, we minimize corrosion and unwanted deposits. In this way, we create durable, low-maintenance, and safe solutions that remain usable for many years.

For water-cooled exhaust systems, reliable backpressure management is essential, especially when the exhaust outlet is positioned below the waterline and pressure varies due to speed, wave action, and changing water depth. Excessive backpressure causes increased engine temperatures, additional fuel consumption, and potential engine damage; with direct consequences for engine manufacturer warranties.

That is why Discom designs not only the exhaust system itself, but also the associated management around prediction, monitoring, and control. For high-speed vessels, for example, we apply a specially designed scoop that creates negative pressure and reduces backpressure. Our engineering combines many years of accumulated practical experience with simulations such as two-phase flow and CFD analyses, supplemented by onboard measurements and validations. This integrated approach ensures that our calculations correspond with reality; a prerequisite for safe, efficient, and long-term reliable maritime installations.