Environmentally friendly, maintenance-free, and proven – water-lubricated bearings have many advantages but are still rare in Danish waters. Henrik Ziska Damsgard from Damzgard Mechanics is trying to change that.
In both the USA and Canada, it is becoming standard to use water-lubricated bearings for stern tubes and rudder stocks – especially to avoid oil slicks in harbors and vulnerable waters. In Denmark, however, they stick with oil, even though saltwater is cheaper, cleaner, and potentially more environmentally friendly.
“You would think that the fishing industry, in particular, would have an interest in clean water, but it is still very rare to see water-lubricated solutions in Denmark,” says Henrik Ziska Damsgard, owner of Damzgard Mechanics and the sole Danish distributor for the Canadian company Thordon Bearings, which has specialized in oil- and grease-free polymer systems.
With oil, you have to analyze, change, and top it up continuously. Water takes care of itself. There are fewer components, and the seals last longer.
Henrik Ziska Damsgard
The basic idea behind a water-lubricated stern tube is simple: you pump seawater in to cool and lubricate the shaft, which eliminates the need for oil and advanced sealing systems. This reduces both operating costs, the risk of leakage, and environmental impact.
“With oil, you have to analyze, change, and top it up continuously. Water takes care of itself. There are fewer components, and the seals last longer,” explains Henrik Ziska Damsgard. The installation is typically a bit more expensive, but in the long run, you get both lower maintenance and better operational economy.
“In the USA and Canada, water-lubricated solutions are more common than oil-lubricated ones, but in Denmark and Europe, we are lagging a bit behind on this front,” says Henrik Ziska Damsgard.
However, development is moving in the right direction. Several newly built electric ferries and patrol vessels – including some of the Home Guard cutters from the 1990s – already use water-lubricated solutions. Henrik Ziska Damsgard sees great potential in future ship design, where both environmental considerations and operational optimization carry significant weight.
“It is a technology that both makes sense and works in practice. We just need to get better at thinking long-term and choosing solutions that last – for both the sea and the economy,” he says.
Damzgard Mechanics is not just a supplier. With a background as technical manager at Hundested Propeller for 13 years, Henrik Ziska Damsgard also offers technical consulting and design assistance to both shipyards and designers who want to switch to the new components.
“We also function as a design office and can help with the adaptation of structures so that Thordon’s products are implemented as effectively as possible – for example, by replacing bronze bearings with the self-lubricating ThorPlas-Blue, which can handle high loads and requires minimal maintenance,” he explains.
