The use of LNG as a fuel is growing in popularity for ships of different sizes and power to provide a solution to increasing fuel costs and reducing exhaust emissions. Using LNG requires storage not only under but also at low temperature. Cooling the gas into a liquid state at the low temperature of approximately -162 ̊C (-260 ̊F) allows it to be maintained at the low pressure of only 3.6 psi (0.25 bar). While cooling plant and well insulated tanks are feasible on a ship, on small vessels - boats, this is not practical. To access the benefits of natural gas operation, a more practical solution for boats is to use compressed natural gas (CNG). The drawback is that CNG is 2.4 times greater in volume than LNG.

In the Netherlands ten percent of automobiles run on LPG and a very small number of boats use is as a fuel, however its use in boats is regarded as being potentially dangerous as it is heavier than air and any escaping gas will accumulate in the bilges. Natural gas on the other hand is lighter than air and any escaping gas is lost to the atmosphere.

Caption: The CNG Water Police 18 ft RIB used to patrol the Netherlands inland waterways and canals.
Image Credit: K.Henderson

This year the Water Police that patrol the Netherlands inland waterways are experimenting with a dual fuel gasoline / CNG Honda outboard powered patrol boat. The boat is a 18 ft (5.6 m) Dolphin RIB powered by a Honda 90 VTEC outboard. In addition to the standard gasoline tank, there is a 24 US gall (90 liter) CNG tank with a capacity for 33 lbs (15 kg) of CNG, held under pressure of approx 3,000psi (~200 bar). The fuel system cold starts on gasoline and when operating temperature is reached switches over automatically to CNG and remains operating on gas under 2,000 rpm. Above that speed it switches over to gasoline to realise the full power of the engine.

In practical terms, the boat can patrol all day on one tank of CNG, when speed is required, it is always available and the performance of the boat is not impaired in any way due to the dual fuel capability. The fuel cost of CNG compared to gasoline in the Netherlands is about half, giving a substantial through life cost saving.

Caption: The 24 gall / 33 lbs CNG fuel tank mounted in the bilges.
(GROENGAS is Dutch for Green Gas!)
Image Credit: K.Henderson

A specially designed coaster for the supply of fish feed to fish farms on the Norwegian coast will be the world’s first LNG-powered coaster. The M/S Høydal, was built at the Tersan Shipyard, Turkey for NSK Shipping, Norway. The ship will operate along the Norwegian coast on a long-term charter for BioMar, Norway. When she enters service in May 2012 with her 2200 t capacity of fish feed she will become the world’s largest fish feed cargo vessel.

Caption: Artist impression of the world’s first LNG fueled coaster, the 2,200t M/S Høydal
Image credit: Tersan / NSK Shipping

The 2,650 dwt vessel has an LOA of 230 ft (70 m), beam 52 ft (16 m) and draft of 20 ft (6.2 m) and will be powered by a single Rolls-Royce Bergen C25:33L6P engine rated at 1,650 kW at 1,000 rpm operating on LNG. Propulsion is by a Rolls-Royce CP propeller and the maximum speed is 14 kn.

The is a 3,200 ct ft (90 m3) LNG tank on board and refueling is planned to be supplied from a permanent bunkering facility near the BioMar factory, once a week. Natural gas (LNG) propulsion will make the vessel environmentally friendly and reduce emissions of NOx (nitrogen oxides) by over 90 per cent.

A feature of the ship is a Graintec Cargo rapid discharge system allowing a fish feed discharge rate of up to 7,000 cu ft / hour (200 m3 /h).

The added capital cost of the LNG installation will be repaid through reduced fuel costs and taxes. The project is partly financed by the Norwegian NOx Fund (tax incentives) which will cover US dollar $3.13 million (NOK 18M) of the estimated total added cost of US dollar 4.87 million (NOK 28M).

Caption: A six cylinder Bergen C25:33L6P propulsion engine.
Image credit: Rolls-Royce Bergen

Specialist ship owner Anthony Veder, Netherlands, new LNG carrier ordered from Mayer Werft, Germany for construction at the Neptun Yard in Rostock is due for delivery in the second quarter of 2012. A direct mechanical drive system is specified for the vessel which is believed to be the first application of its type: previous LNG carriers use a dual fuel diesel electric arrangement. The Anthony Veder Group presently has a fleet of 21 gas tankers with a further four ships on order.

Caption: Anthony Veder’s new LOA 512 ft (156 m) LNG carrier is the first vessel of its
kind to use a direct mechanical drive with a dual fuel engine.
Image credit: Anthony Veder

The new LNG carrier has a capacity of 550,000 ft3 (15,600 m3) with a LOA of 512 ft (156 m) and beam of 74 ft (22.7 m) and is designed for the distribution of LNG rather than long distance transporting from the major gas fields. Its main area of operation will be in the North Sea and Baltic Sea Emission Control Areas (ECA).

The single shaft propulsion system comprises a Wärtsilä 50DF dual-fuel engine going through a reduction gearbox to a controllable pitch propeller. Two Wärtsilä 20DF dual-fuel auxiliary engines provide electrical power. Wärtsilä dual fuel engines operate on LNG as the main fuel with pilot diesel fuel injection to initiate combustion. If required the engines can operate on diesel fuel only.

Operation on LNG all but eliminates SOx emissions and reduces the production of CO2 and NOx to levels that are sufficiently low as to be within the IMO Tier 3 NOx regulations and compliant with the requirements of the ECAs.

Caption: A Wärtsilä 50DF series dual-fuel engine
Image credit: Wärtsilä Corp.

DNV is heading the project FellowSHIP which is the name given to a joint industry R&D project to investigate sustainable energy generation for marine and offshore applications. The other partners are the owner of the test ship MV Viking Lady, Eidesvik Offshore and ship designer/power electronics developer Wärtsilä with overall financial support for the project being provided by the Research Council of Norway.

Caption: The hybrid 6,200 dwt MV Viking Lady Offshore Supply Vessel, owned by Eidesvik Offshore,
is the world’s first application of a merchant ship using fuel cell propulsion.
image credit: Eidesvik Offshore

The 6,200 dwt MV Viking Lady Offshore Supply Vessel was built in 2009 and has an LOA of 300 ft (92 m). beam of 69 ft (21 m) and draft of 31.5 ft (9.6 m). There are four Wartsila 6L34DF gensets each with an output of 2.6MW able to run on diesel or LNG (Liquefied Natural Gas) fuel. In addition there is a MTU 330kW fuel cell operating on LNG, which is the world’s first application in a merchant ship of a fuel cell providing propulsion power. Since its installation in 2009, it has been running successfully for over 18,500 hours.

The first phase of the FellowSHIP project started 2003 with a feasibility study, development of concepts and initial design studies. The second phase (2007-2010) finalized the development and installation of the marinizied fuel cell power package and its integration with new electronic systems, power electronics and control systems technology. The project also includes safety and reliability studies and approval and rule development.

The third and final phase (2011-2013) adds an energy storage capability in the form of a battery pack thereby creating a full hybrid energy system. The battery is a lithium-polymer type with a solid polymer composite electrolyte and is built up from 6.5 kWh modules to give a total capacity of 0.5 MWh and is capable of delivering 5MWh over a short period of time. A full scale hybrid installation would be expected to include a 2 - 3 MWh battery pack, but the 500 kWh pack is sufficient to demonstrate the technology. The battery pack and battery management system, supplied by Corvus Energy, Canada, is being tested on land will be installed on board in 2013.

Compared to a traditional ship, MV Viking Lady has annually reduced harmful NOx emissions by 180 t, an amount equal to emissions from 22 000 cars. CO2 emissions are reduced by 20 percent. A future hybrid power solution including LNG-fuelled steam turbines and fuel cells, could reduce the ship’s fuel consumption by up to 30-50 percent, CO2 emissions by up to 50 percent, and NOx , SOx and particle emissions to negligible values.

Caption: Cutaway drawing of the MTU 330kW fuel cell operating on LNG,
onboard the MV Viking Lady. Since its installation in 2009, it has been running
successfully for over 18,500 hours.
Image credit: MTU Friedrichshafen

Owners of the Russian nuclear icebreaker fleet, Rosatomflot, have announced a new giant LK60 Class of nuclear icebreaker, construction of which is planned to commence later this year.

Caption: Artist’s impression of the LK60
Image credit: Rosatomflot

Tenders for the project will be invited this summer for the estimated US $1.4 billion (€ 1.1 billion) project which is expected to have a construction duration of six years giving an in service date of 2018.

The tender is open to foreign bidders. A previous nuclear icebreaker, the Vaygach was built in Finland and completed in 1990 with the nuclear plant being installed at the Russian Baltiysky Shipyard in St Petersburg. The most recent Russian nuclear icebreaker is the 50 Let Pobedy built at Baltiysky Shipyard and completed in 2007.

Caption: The 34 m beam cuts a wider channel for larger tankers to transit the Northern Sea Route
Image credit: Rosatomflot

The LK60 has a massive beam of 112 ft (34 m) and draft of up to 35.4 ft (10.8 m). This will allow the creation of a wide enough channel through the ice for larger tankers. The nuclear reactor is rated at 60MW and will power a three shaft propulsion arrangement, capable of operating in ice thicknesses of up to 9.8 ft (3.0 m).

As the extent of ice recedes due to global warming, the prodigious power of the LK60 will allow Rosatomflot to keep the Northern Sea Route open through the winter months, thereby offering this shorter route between Europe and Asia as a permanent all year round, rather than seasonal route.

When the LK60 enters service, it will replace one of the Arktika class nuclear icebreaker  and one Taimyr class nuclear icebreaker.

In December 2011, the United Shipbuilding Corporation, Russia received and order from the Russian Federal Agency for Maritime and River Transport Rosmorport for four diesel electric icebreakers, one of 25 MW and three of 16 MW.

Caption: Drawing of the LK60 showing hull and propulsion arrangement
Image credit: Rosatomflot

Details of the propulsion system of the world’s first seagoing hybrid ferry have been released, following the announcement of the start of construction. Two ROPAX (roll-on, roll-off passenger) ferries are contracted to Ferguson Shipbuilders, Scotland by Caledonian Maritime Assets Limited (CMAL) for delivery in May and August 2013.

Caption: Drawing of world’s first seagoing hybrid ROPAX ferry.
Image credit: CMAL

The vessel has a LOA of 142 ft (43.5 m), beam 40 ft (12.2 m) and draft of 5.7 ft (1.73 m) with 135 tonnes  deadweight. Maximum capacity is 23 automobiles, 2 heavy good vehicles and 150 passengers. The ferry is designed to operate on a wide range of routes at all tidal states that may include some small islands with steep loading ramps with a gradient of as much as 1:8.

The hybrid propulsion system consists of three Volvo Penta D13 generator sets of 360 kW at 1500 rpm, two 700 kWh lithium ion battery groups and two 375 kW electric propulsion motors, each driving a Voith Schneider propulsion unit. Model tank tests carried out at the Hamburg Ship Model Basin (HSVA) predict a cruising speed of 9 kn with a draft of 5.7 ft (1.73 m) that requires only 276 kW, thus in normal use, with good weather  one genset is sufficient to supply the needs of the ferry, with a further two gensets in reserve.

It is planned to use a shore to ship power supply during overnight ferry stopovers for hotel load and battery charging, thereby eliminating exhaust, vibration and noise emissions.

The overall advantages for using a hybrid propulsion systems is an estimated 20 per cent  reduction in harmful emissions with zero emissions in harbor and fuel savings between five and ten per cent.

Caption: Block diagram of the Modes of Operation.
Image credit: CMAL

Many of the world’s ports are located in major cities, in fact to be more accurate where there are  major ports, large cities have grown around them.

As increasing attention is focused on the reduction and eventual elimination of greenhouse gas emissions such as nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM), port authorities are under pressure from their governments to play their part in improving air quality.

Caption: Schematic of shore to ship power supply
Image credit: ABB

Ships visiting port have to maintain onboard services that require electrical power - usually provided by onboard auxiliary generators, creating noise, vibration and exhaust pollution.

ABB offer a shore to ship power supply system that can connect any ship to the grid, thereby allowing “cold ironing” or the shutting down of on board engines while in port.
According to them, the 100,000 vessels docking annually at the world’s 4,500 ports produce 900 million tonnes of CO2 - equal to 220 coal fired power stations. ABB also give an example of a cruise ship using shore power in port that not only reduces genset running hours and exhaust emissions to zero, it could save up to $750,000 in operational costs.

The ABB system comprises transformer and converter substations with berth terminal(s). As the standard grid frequency in Europe is 50 Hz (Hertz) while most ships use 60 Hz, frequency and voltage conversion is required with automatic control of the synchronization process to achieve a seamless power transfer without disruption of the onboard services

The first installation was completed last year at the port of Gothenburg, Sweden and they are  currently installing two new systems for completion this year in Sweden and the Netherlands.

The new Netherlands installation is at the port of Hoek van Holland and will permit the simultaneous connection of two Stena Line vessels to the local grid. On board modification to the electrical and automation systems to enable shore-side power supply will be carried out on two ROPAX (roll-on/roll-off passenger) vessels as well as on two RORO (roll-on/roll-off) ferries.

The second installation in Sweden, at the port of Ystad, will have the world’s largest shore connection frequency converter and is capable of supplying up to seven ships simultaneously.

Caption: Quay terminal facility for shore to ship power supply
Image credit: ABB

Rolls-Royce Marine is to deliver gas engines and propulsion systems for the world’s first Liquid Natural Gas (LNG) fuelled tugs. The two vessels, with the dimensions of  LOA of 115 ft (35 m), beam of 50 ft (15.4 m) and draft of 24.6 m (7.5 m), have been ordered by Buksér og Berging AS, Norway and are scheduled to enter service in late 2013 for offshore oil & gas industry duties along the Norwegian coast.

Caption: Drawing of the world’s first LNG tug showing single LNG fuel tank and propulsion details.
Image Credit: Rolls-Royce Marine

Each tug will be powered by two in-line six-cylinder Bergen C25:33L6P series spark ignition, lean burn gas engines based on the C diesel series. The output power of this Tier III compliant model is in the approximately range of 1,880 hp to 2,346 hp (1,400 to 1,600 kW) at 900 or 1,000 rpm respectively. A feature of the C series is simplified maintenance achieved by using a two piece connecting rod, allowing the cylinder liner, piston (including upper con-rod) and cylinder head to be removed / exchanged as a single unit, thereby  reducing overhaul time and cost considerably.

Unlike some other LNG engines, the Bergen gas engines have spark plugs allowing it to operate purely on gas and not requiring pilot diesel fuel injection to initiate combustion. It therefore  eliminates the requirement of a secondary (diesel) fuel system and supply.

Opposite to the situation with diesel engines, LNG engines produce lower NOx emissions at lower engine loads. This is advantageous for tugs which have a duty cycle of majority use at low power outputs. NOx emissions for these new tugs is very low with an estimated reduction of about 92 per cent: the reduction in Green House Gas (GHG) emissions is up to 17 per cent. Further emission reductions are 98 - 100 per cent for SOx and 98 per cent  particulates.

Caption: An in-line Bergen C25:33L9P series spark ignition, lean burn LNG engine, is based on the C diesel series.
Image Credit: Rolls-Royce Marine

The product tanker MV Bit Viking has completed the first ever conversion worldwide, of a vessel from HFO to LNG and is now in service with Swedish owners Tarbit Shipping. Operating along the Norwegian coastline by Statoil. the very low emissions now attainable will qualify for lower Norwegian NOx emission taxes.

Caption: MV Bit Viking after conversion showing the two deck
mounted 17,850 ft3 (500 m3) Wärtsilä LNGPac tanks.
Image Credit: Wärtsilä Corp.

The Bit Viking has a very high safety specification. Delivered in 2007, the double hulled product tanker of 24,783 dwt has an LOA of 580 ft (177 m) and a beam of 82 ft (26.3 m). The original propulsion was with twin Wärtsilä 6L46B engines each with an output of 7,842 hp (5,850 kW) driving twin screws and features two separate engine rooms, double steering gears, rudders and control systems.

Apart from the modifications to the ship for the LNG refueling, storage and supply, the conversion required a major rebuild of the engines. The Wärtsilä 6L50DF engines with output of 7,460 hp (5,700 kW), although having the same stroke as the old engine, required increasing the cylinder bores from 460 mm to 500 mm and replacing most of the engine parts.

Operation of the engines on LNG uses Wärtsilä’s LNGPac system with two 17,850 ft3 (500 m3) LNG tanks located on deck. The tanks are of sufficient capacity to give an autonomy on LNG fuel of approximately 12 days on 80% load. As the engines are dual fuel, reverting to HFO operation is always and option.

The planning of the conversion project commenced in Mar 2010, docking and conversion work was in Aug 2011 and sea trials took place in Sept 2011. Safety analysis and approval was undertaken by Germanischer Lloyd (GL) classification society.

Caption: A Wärtsilä 6L50DF engine with output of 7,640 hp (5,700 kW).
Image Credit: Wärtsilä Corp

DDG 1000 Program Tests Integrated Power System

By Joseph Battista, Naval Sea Systems Command Public Affairs

PHILADELPHIA (NNS) -- The Chief of Naval Operations (CNO) observed live tests of the DDG 1000 Integrated Power System (IPS) at the Land Based Test Site at Naval Surface Warfare Center Carderock Division - Ship Systems Engineering Station (NSWCCD-SSES) July 22.

DDG 1000 will be the first U.S. Navy surface combatant to use electric power for propulsion and ship services. An IPS generates the total ship electric power requirements, then distributes and converts it for all ship loads, including propulsion, combat systems and ship services. The first successful test of the IPS occurred May 11.

CNO Adm. Gary Roughead received an overview of the DDG 1000 program from Capt. James Downey, DDG 1000 program manager from Program Executive Office (PEO) Ships, and a tour of the test site by Matthew Stauffer, NSWCCD-SSES DDG 1000 IPS LBTS program manager.

"Providing the CNO an update on the DDG 1000 Program and demonstrating the equipment in operation was a unique opportunity to highlight the significant progress the program has made," said Downey.

"It is rewarding to see the hard work of our Philadelphia engineers and industry partners being recognized by the chief of naval operations," said Patricia Woody, Machinery Research and Engineering Department head at NSWCCD-SSES. "DDG 1000 is currently under construction, and the testing being conducted on the IPS at the LBTS will greatly reduce ship activation timelines, therefore providing overall cost savings to the Navy."

The IPS is a unique design integrating the power system with fight through power to allow for automatic reconfiguration following damage to the power distribution system. The next test, scheduled for early 2012, will integrate and test portions of the DDG 1000 Engineering Control System software with the IPS to verify software and hardware compatibility.

The lead ship of the DDG 1000 class, USS Zumwalt, is more than 50 percent complete and scheduled to deliver in fiscal year 2014, with an initial operating capability in fiscal year 2016. The second ship, USS Michael Monsoor (DDG 1001), is approximately 20 percent complete.

As one of the Defense Department's largest acquisition organizations, PEO Ships, an affiliated PEO of NAVSEA, is responsible for executing the development and procurement of all destroyers, amphibious ships, special mission and support ships, special warfare craft, and foreign military sales.

NSWCCD-SSES provides the Navy's primary technical expertise and facilities for Naval machinery research, development and life cycle engineering.

For more news from Naval Sea Systems Command, visit www.navy.mil/local/navsea/.