December 10, 2019 – Rolls-Royce and Canadian vessel designers Robert Allan have developed 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 8V4000M55RN 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.
Rolls-Royce and Robert Allan collaborated to design the gas-powered shallow-water push boat based on the proven Robert Allan RApide 2800-Z2 design which is already used on some diesel-powered vessels on the River Amazon. The vessel design was specially modified for LNG to accommodate the two 746 kW MTU 8V4000M55RN engines (complete with IMO Tier III emission control systems) and the entire LNG supply system – also available from Rolls-Royce – as well as the gas control and safety systems and the overall vessel control system.
The hull – externally unchanged – was redesigned to accommodate the 70 cubic meter gas tank as well as the usual engine accoutrements, and to provide crew with a pleasant working environment. The lower crew cabins, saloon and galley were moved up one level, and the deckhouse was enlarged.
The Approval in Principle from DNV GL certifies that the design complies 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 over 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 & 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 and Rolls-Royce confirms that the decision was right to develop a lean-burn 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 & Offshore Americas.
Rolls-Royce is shortly to 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.
Technical data for the RApide 2800-G shallow-water push boat:
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