Rolls-Royce and Robert Allan Ltd. present the world’s first LNG-powered shallow-water push boat

December 11, 2019

Joint development for environmentally friendly and climate-friendly transportation on inland waterways

Classification society DNV GL grants “Approval in Principle” at International Workboat Show in New Orleans

Robert Allan Ltd. and Rolls-Royce have developed what is believed to be the world’s first shallow-water push boat powered by LNG natural gas engines. At the International Workboat Show in New Orleans, Classification Society DNV GL gave its “Approval in Principle” to the new design. Powered by two MTU 8V 4000 M55RN natural gas engines from Rolls-Royce and designed for use on inland waterways, the push boat is more cost-effective to operate, and produces less pollutants and climate-unfriendly exhaust gases than vessels with conventional propulsion systems.

Robert Allan Ltd. and Rolls-Royce collaborated to design the gas-powered shallow-water push boat based on the proven Robert Allan Ltd. RApide 2800-Z2 design which is already used on some diesel-powered vessels on the Amazon river. The vessel design was specially modified for LNG to accommodate the two 746 kW engines (complete with IMO Tier III emission control systems) and the entire LNG supply system – also provided by Rolls-Royce – as well as the gas control and safety systems and the overall vessel control system.

The hull – externally unchanged from the RApide design – was internally redesigned to accommodate the 70 m3 gas tank as well as the usual engine accoutrements, and to provide the crew with a pleasant working environment. The lower deck crew cabins, salon and galley were moved up one level and the deckhouse was enlarged.

The Approval in Principle from DNV GL certifies that the design complies in principle with the Classification Society’s rules for classification of maritime vessels and the international safety regulations for vessels using gas or other low-flashpoint fuels. It is an independent evaluation of the design concept within a given framework and states that the design is fundamentally feasible and there are no fundamental implementation concerns.

LNG (liquefied natural gas) is a fuel now gaining traction in maritime circles, enabling operators to reduce emissions that are harmful to the environment and to the climate. LNG engines produce no particulate whatsoever, emitting significantly less NOx than diesel engines, and are more climate-friendly overall. DNV GL expects natural gas to cover 40% to 80% of all vessel propulsion power requirements by 2050. In addition, gas, where available, offers lower running costs.

Stefan Müller, who heads up the Marine and Naval Application Center at Rolls-Royce’s Power Systems business unit, sees the use of high-speed, pure gas engines like the MTU Series 4000 as offering great potential in ports, coastal applications and inland transportation. To unlock this potential, a reliable fuel supply infrastructure will be required.

The interest of the market regarding the design study of Robert Allan Ltd. and Rolls-Royce confirms that the decision was right to develop a lean-burn MTU gas engine. We have found operators across the globe who have seen the benefits of operational costs in addition to the reduction of environmental impact,

says Christof von Bank, Director of Sales, Marine and Offshore Americas at Rolls-Royce.

The use of LNG as a fuel for use on the worlds navigable rivers is logical and a natural alternative to more traditional fuels. Robert Allan Ltd is pleased to have worked with Rolls-Royce to develop this design and we look forward to seeing this vessel and its unique propulsion system put in service.

says Mike Fitzpatrick, CEO of Robert Allan Ltd.

Technical data for the RApide 2800-G shallow-water push boat is as follows:

  • Engines: 2 x MTU 8V 4000 M55RN, IMO Tier III
  • Power output: 746 kW each
  • Length overall: 28 m
  • Beam: 10.05 m
  • Topsides: 3.2 m
  • Draught: 2.5 m
  • LNG tank capacity: 70 m³

Rolls-Royce will soon deliver its first MTU 8V 4000 M55N gas engines to municipal works company Stadtwerke Konstanz in southern Germany. These will be used to power the first LNG-powered car ferry on Lake Constance.

For more information on this design or any other Robert Allan Ltd. design, please contact