- What is new
- POSCO and Hanwha Ocean signed a memorandum of understanding on 15 October to secure and build a demonstration LNG carrier using high-manganese steel cargo tanks. Hanwha Ocean is to lead vessel construction and the partners intend to collect an operating record for safety, durability and efficiency. This is a planned demonstrator, not an operating cargo-containment system. POSCO says its high-manganese steel has already been used in LNG fuel tanks and other applications on 51 ships, but moving from relatively small fuel tanks to full cargo tanks is a separate scale and qualification challenge. Sources: POSCO, “POSCO-Hanwha Ocean to strengthen K-shipbuilding competitiveness with high-manganese steel,” 15 October 2026, https://www.posco.com/homepage/docs/kor7/jsp/prcenter/press/s91c600110v.jsp?idx=3683&onPage=1; The Korea Times, “POSCO, Hanwha Ocean team up on high-manganese steel LNG cargo tanks,” 15 October 2026, https://www.koreatimes.co.kr/business/companies/20261015/posco-hanwha-ocean-team-up-on-high-manganese-steel-lng-cargo-tanks.
- How it works
- High-manganese cryogenic steel is formulated to retain strength and impact toughness at LNG temperatures below minus 163 degrees Celsius. POSCO describes an independent tank fabricated separately and installed in the hull, with the primary steel shell surrounded by insulation and supported against vessel loads. Compared with membrane containment, an independent tank changes the structural load path and shipyard integration sequence. The material choice does not by itself determine boil-off rate: insulation design, tank geometry, support heat bridges, vapour-space management and operating profile remain decisive.
- Why it matters
- MyLNG analysis: the proposal could diversify cargo-containment materials and reduce exposure to nickel-alloy supply, but the strongest claims remain manufacturer claims. POSCO says the concept can be configured from ultra-low to economic boil-off rates, resist sloshing without operating restrictions and shorten construction time; no public full-scale voyage data, class approval package, fatigue results, weld-production record or quantified BOR test conditions were identified in the reviewed material. The demonstrator matters precisely because fuel-tank service does not prove full-cargo-tank performance.
- LNG / shipping impact
- If full-scale trials and class review support the design, shipowners could gain another containment option for LNG carriers, bunkering vessels and FSRUs. Applicability will depend on payload and hull-volume penalties, tank-support arrangement, inspection and repair practice, welding productivity, terminal compatibility and commercial licensing. Maturity is recorded as prototype: the underlying steel is commercially used in fuel tanks, while the announced LNG cargo-tank application is still seeking a demonstration vessel.