Demo Case

CNG powered RSD shiphandling tug

This demonstrator case will provide a prototype harbour tug, namely the RSD (Reverse Stern Drive) 2513 CNG, which operates with compressed natural gas (CNG) as a fuel. For the time being there are four tugs operational with liquefied natural gas as a fuel worldwide. These tugs use medium speed engines, which are big, heavy and expensive. The presented demonstrator would use high speed engines, provided by MTU, to directly drive the thrusters. The use of these high speed natural gas engines offers a high power density, matching the compact ship design, combined with cost-efficiency, compared to the medium speed engines, being used in the existing LNG fuelled tugs. It will be the first use of high speed gas engines in a maritime application in this power range.

The tug will also be of an entirely new type with improved hydrodynamic characteristics, which will increase the efficiency by allowing a smaller tug to do the same job in a safe way. To optimise the hydrodynamic behaviour, comprehensive computational fluid dynamics (CFD) calculations and model scale tests will be carried out. In LeanShips work is being carried out to get a functional unit in place to compare the effectiveness of different tugs. The new design will also allow the use of a smaller crew (three instead of four to five), which contributes to a decrease in operational costs, and to making natural gas a competitive green alternative to conventional tugs.