GTT has been selected by HD KSOE to design the containment tanks for the world’s first four large-scale, three-cargo-tank LNG carriers being built for BW LNG. By eliminating an entire tank division to optimize the cargo-volume-to-insulation ratio, this breakthrough naval architecture expands payload capacity to 177,000 m³ and drops the daily boil-off rate to an ultra-efficient 0.08%.
Paris, France | May 20, 2026 – In what is being hailed as the most significant radical shift in liquefied natural gas carrier (LNGC) architecture since the 1970s, French cryogenic engineering specialist GTT has been selected to design the containment systems for the world’s first large-scale three-cargo-tank LNG carriers.
Commissioned by South Korean shipbuilding powerhouse HD Korea Shipbuilding & Offshore Engineering (HD KSOE) on behalf of leading shipowner BW LNG, this revolutionary design breaks the conventional four-tank blueprint that has dominated global gas shipping for over five decades.
The innovative engineering layout will be integrated into a series of four newly ordered 177,000 m3 mega-carriers being built at the HD Hyundai Samho shipyard, scheduled for progressive deliveries beginning in the fourth quarter of 2028 through mid-2029.
The Three-Tank Paradigm Shift: Volumetric & Thermal Gains
By reducing the number of cargo holds from four to three, the collaborative engineering teams at GTT, HD KSOE, and BW LNG have eliminated an entire cofferdam (the insulated void space between tanks), liquid cargo handling grid, and pump tower assembly.
This simplified naval architecture translates to immediate commercial advantages, primarily through optimized space utilization and highly advanced thermodynamics.
Key Technological Advancements:
- Elongated Hold Geometry: The simplified three-tank architecture permits a dramatic tank length extension of up to 55%.
- Volumetric Capacity Bonus: Overall payload capacity expands by an additional 3,000 m3, lifting the net cargo volume to 177,000 m3 (compared to the mainstream 174,000 m3 industry baseline).
- Dimensional Consistency: Crucially, this capacity bump is achieved without altering the hull’s principal exterior dimensions, ensuring identical terminal compatibility, draft constraints, and mooring parameters worldwide.
Comparative Architectural Analysis
| Feature | Conventional LNGC Standard | Next-Generation BW LNG Concept |
| Tank Configuration | 4 Separate Cargo Tanks | 3 Optimized Cargo Tanks |
| Total Cargo Capacity | 174,000 m3 | 177,000 m3 (+3,000 m3 payload) |
| Maximum Tank Length | Baseline | Up to 55% Increase |
| Guaranteed Daily BOR | 0.085% – 0.10% | 0.08% per day (Ultra-low boil-off) |
| Propulsion & Machinery | Standard Dual-Fuel | X-DF 2.2 with VCR & Shaft Generators |
Advanced Thermodynamics: Slashing Boil-Off Gas (BOG)
From a marine energy perspective, the ultimate asset of the three-tank configuration lies in its thermodynamics. By condensing the cargo into three units instead of four, the design vastly optimizes the ratio of LNG cargo volume to the surrounding insulation surface area.
Fewer thermal bridge pathways mean far less heat ingress into the cryogenic liquids, resulting in a guaranteed daily cargo boil-off rate (BOR) tightly capped at an industry-leading 0.08% of volume per day. When paired with a 2.1 ton/hour on-board reliquefaction plant, methane loss is virtually neutralized.
To mitigate the heightened sloshing forces and dynamic liquid impacts created by much longer individual tanks, the vessels will feature GTT’s Mark III Flex membrane containment system, backed by localized membrane structural reinforcements. This engineering adjustment secures class approval from DNV to carry partial loads safely, giving cargo owners full parcel-size loading flexibility.
Executive Perspectives
The historic four-ship deal consists of a pair ordered in November 2025 and an option exercise for two additional vessels finalized in May 2026, costing roughly $253 million per hull.
“This project marks a significant step forward in the evolution of LNG carrier design, with major gains in operational efficiency and environmental performance,” said François Michel, CEO of GTT. “It demonstrates GTT’s proactive approach in working closely with shipyards and shipowners to address the evolving needs of the LNG transport market.”
For BW LNG, the asset class directly targets upcoming, strict global emission baselines by incorporating high-end efficiency kits, including WinGD X-DF 2.2 engines with Variable Compression Ratio (VCR) technology.
“BW LNG is proud to pioneer the industry’s first three-tank LNG carrier design across four of our new buildings,” said Yngvil Åsheim, CEO of BW LNG. “This innovative, proven configuration delivers increased cargo capacity, with greater operational flexibility and enhanced operational performance. This collaboration reflects BW LNG’s commitment to practical innovation, strengthening our ability to support global LNG demand with lower emissions.”
Representing the manufacturing side, HongRyeul Ryu, Chief Technology Officer of HD Hyundai Heavy Industries, added that the breakthrough “strengthens our technological leadership in the LNG shipping sector” at a time when next-generation efficiency determines shipbuilding market share.
GTT (Gaztransport & Technigaz)
GTT (Gaztransport & Technigaz) is a French technology and engineering group with expertise in the design and development of cryogenic membrane containment systems for use in the transport and storage of liquefied gases. Over the past 60 years, the GTT Group has developed innovative technologies used in LNG carriers, floating terminals, onshore storage tanks, and multi-gas carriers.
Committed to building a sustainable world, GTT develops new solutions to support shipowners and energy providers in their journey towards a decarbonized future. This includes systems enabling commercial vessels to use LNG as fuel, cutting-edge digital solutions to enhance vessels’ economic and environmental performance, and active innovation in low-carbon solutions.
Source: GTT