New LNG-Fueled Containership Design

LNG-fuelled vessels promise a solution to many of the environmental challenges facing shipping over the next 30 years. To meet the needs to cut CO² emissions and maximize efficiency wherever possible, IPP Ingenieur Partner Pool developed STREAM, the new containership design for LNG-powered containerships. The concept, which has been assessed by GL and given a certificate of approval, is for a range of liner or feeder vessels from 3,000 TEU to 4,200 TEU for worldwide service.

STREAM 4200 LNG has a 32.25-metre beam which allows passage through the existing Panama Canal locks. A draft of 10.50 m to 12.00 m means the vessel can operate worldwide, including the Kiel Canal between the Baltic and North Sea. The vessel is subdivided into several double 40-foot holds. The forward hold is covered and designed to carry dangerous goods. The cargo holds behind this are of open-top design, including the hold behind the superstructure located semi-aft. The forward mooring arrangement is fully sheltered by a large cover which forms an integrated part of the unique wave-breaking structure. The aft one is covered by the aft container stack. The layout can be configured to suit multiple shipping routes, with optimal flexibility as it is based on existing technology.

Regarding cargo loading, the design of the vessel makes it possible to handle the full range of container sizes in use today. Apart from this adaptability in sizing, the container stacks on the deck of the vessel are laid out to achieve higher stack weights and enable individual storage patterns and loading operations for each individual cell. According to Hans-Jürgen Voigt, Managing Director of TECHNOLOG, marketing partner of IPP, all of the 40 ft container slots in the hold as well as three tiers of the deck slots have been fitted for reefer containers. Ventilation systems have been developed in order to suit these reefer slots. The cargo storage and lashing equipment as well as the stack-splitting system have been custom-designed in cooperation with the international cargo and load handling specialist CARGOTEC. STREAM ships can also be fitted with electrically-operated deck cranes at outfitting or at a later time if required.

The vessel’s bunkering systems have been developed jointly with TGE Marine Gas Engineering and include a fixed bunker tank inside the vessel and a novel portable deck-mounted LNG tank system which can be used to provide extra capacity. For bunkering, the fuel containers will be connected to a newly developed docking station.

Systems to assure the safety of the ship’s crew include passages below deck that run the length of the entire vessel, providing access to the cargo and machinery spaces and the crew’s quarters.

As Anti-Piracy measures, armoured shutter plates can be closed in the central entrance lobby to cut off the interior of the vessel, including the deck house, from the deck.

In respect of energy saving and energy efficiency design, a single screw is directly driven by a dual-fuel, two-stroke, 22.9 MW engine developed specifically for LNG applications by MAN. The same dual-fuel system is used for the auxiliary power generators and boilers. Exhaust gas boilers and waste heat recovery equipment are installed. Beyond merely saving fuel, the efficiency of the propulsion system means that a STREAM ship can operate in a wide variety of ways. When loaded to medium draft, the main engine can provide all of the vessel’s required electric and propulsive power. When needed, the auxiliary engines can generate additional power for added speed or to boost power in poor weather conditions. As a whole, the design and operational features result in significant lower fuel consumption compared to any designs running on standard fuel. With some extra initial investment, the vessel can take advantage of a waste heat recovery system (WHRS) for even greater fuel efficiency. An exhaust gas boiler system can be installed that feeds an MAN Diesel & Turbo turbo generator set for electric power generation. An optional, “minimum fuel- controlled” power management system from Siemens can reduce fuel consumption further, thereby cutting overall energy costs. Estimates suggest that the slightly higher initial costs of installing such a system will pay off in approximately four to six years depending on ECA zone application and fuel price development.

The ship’s design in respect of hull optimization includes hull lines that minimize fuel consumption as well as resistance in water and air while maximizing cargo capacity and ensuring maximum stability. With the support from FutureShip, the designers were able to model a large number of design variants, select the traits desired, and then modify the best variants to arrive at an optimal hull form. Improved hull lines allow installation of a highly efficient, relatively slow-running propeller from project partner MMG (Mecklenburger Metallguss GmbH). A Becker Marine rudder ensures maximum manoeuvrability. Upcoming regulations will require extra investment to meet stricter emission requirements, even for ships running in dual fuel mode, to meet strict sulphur, carbon dioxide and nitrogen limits for ECA zones and harbour areas.

Features the LNG-fuelled STREAM 4200 LNG can be summarized as follows:

All consumers are designed for unrestricted LNG and fuel oil operation
Full IMO Tier3 compliance at sea and in ports with best EEDI index far below any require-ment
No ballast water when fully loaded and bunkered
15% reduced operation cost using LNG instead of sulfur reduced fuel oil
20% reduced CO2 emission
Full flexible container loading capabilities ranging from 20ft to 49ft container
Full reefer payload capacity can be supported

As currently configured, the STREAM already meets all of the upcoming regulations to control air emissions from shipping. In addition, STREAM ships boast an EEDI, based on preliminary calculations, that is significantly beneath the required baseline for 2025.