VESSEL REVIEW | Muria – Versatile diesel-electric pusher tug trio for Chemgas Shipping

Barkmeijer Shipyards, a company under Netherlands-based Thecla Bodewes Shipyards, has handed over three shallow-draught pusher tugs in a series ordered by local operator Chemgas Shipping.

In keeping with the owner's tradition of naming its inland tugs after volcanoes found around the world, Maderas takes its name from a volcano in Nicaragua while Merapi and Muria have been named after two volcanoes in Indonesia. Each tug has an LOA of 29.5 metres, a moulded beam of 11.4 metres, a draught of 1.2 metres, and space for five crewmembers. The vessels' shallow-draught design was specifically selected by Chemgas to make river transport possible even during the dry periods in a year when water levels throughout Europe drop below ideal levels.

A diesel-electric arrangement consisting of a trio of Caterpillar C18 small diesel generators supply over 1,140 kW of propulsive power for the electric motors on each tug. The diesel-electric propulsion is unique in that it can allow a tug to draw power solely from a fourth Caterpillar C18 generator installed on a connected non-self-propelled barge as an alternative source to the three main generators. In addition to maximising each tug's endurance, this operating mode proves adequate for low-speed cruising in narrower and shallower waters.

Chemgas said the diesel-electric propulsion will enable each tug to better manage the required power under different sailing parameters, namely, sailing upstream or downstream, laden, or in ballast. Thanks to an optimised connection between the tug and the barge (i.e. the fourth Caterpillar generator), the combination will help achieve a significant reduction in fuel consumption, as the distribution can be deliberately set to ensure that just the right amount of propulsive power is delivered even with the changes in the tug's operating profile.

The owner has also claimed that the diesel-electric system will allow for easier upgrades once newer alternative fuel options become available. Barkmeijer said the tugs were thus designed from the outset to be capable of undergoing modifications in the future to allow the installation of other types of low-emission propulsion systems such as fuel cells and batteries.

Each tug has also been fitted with a JCB 80kVA diesel generator for supplying electrical power for all onboard systems.

Maderas, Merapi, and Muria have already begun operating on Chemgas' inland shipping routes that pass through Vlissingen, Basel, Antwerp, and Rotterdam. The owner said each tug has been paired exclusively with a tank barge with a total capacity of between 2,700 and 3,000 cubic metres and a draught of only 1.2 metres even when laden with with 250 tonnes of cargo. Each tug-and-barge combination will measure 135 by 11.4 metres.

See more stories from this month's Tug and Salvage Week here.