The Historical Background of Independent Development of Propellers for Large LNG Carriers
Liquefied Natural Gas (LNG) is a vital type of clean energy amid the global transition of energy structures, and its transportation relies on special vessels known as large LNG carriers. Hailed as the "jewel in the crown" of the shipbuilding industry, LNG carriers integrate the most cutting-edge technological achievements of the modern shipbuilding sector. As the core component of a vessel’s propulsion system, propellers directly govern the sailing efficiency, operational stability and safety of LNG carriers. For a long time, the technologies for designing and manufacturing propellers for large LNG carriers have been monopolized by a small number of overseas enterprises. Domestic LNG shipbuilding companies have had to procure these propellers from abroad at exorbitant costs, which has not only slowed the development pace of China’s LNG carrier industry but also brought about hidden risks to supply chain security.
With the continuous expansion of China's natural gas import volume, market demand for LNG carriers has been rising year by year. According to industrial statistics, China's LNG imports exceeded 100 million tons in 2025, and the required number of large-scale LNG carriers exceeded 100 vessels. Against this market backdrop, independently developing propellers for large LNG carriers and breaking overseas technological monopolies has become a pivotal core technology that China's shipbuilding industry must conquer. The national 14th Five-Year Plan has designated the domestic production of key equipment for large LNG carriers as a major special project, offering policy backing and project foundations for the independent research and development of large LNG carrier propellers. Domestic shipbuilders have accordingly launched targeted research efforts on relevant technologies.
From a technical perspective, the propellers of large LNG carriers are subject to far stricter requirements than those of ordinary ships. LNG carriers boast large tonnage; large LNG vessels with a capacity of over 170,000 cubic meters have a full load displacement exceeding 100,000 tons, so their propellers need to deliver sufficient and stable thrust during navigation. Meanwhile, LNG carriers transport liquefied natural gas, which is low-temperature, flammable and explosive, imposing extremely stringent limits on hull vibration. The design and manufacturing of propellers must rigorously control exciting force to prevent safety hazards triggered by vibration. In addition, most large LNG carriers adopt a twin-skeg hull design, which requires propellers to match the special hull structure, with exacting standards in terms of diameter, blade profile, machining precision and other parameters. These technical barriers constitute the primary hurdle on the path of independent research and development.
The Technical Research Journey of Propellers for Domestic Large-Scale LNG Carriers
China's independent research and development of propellers for large LNG carriers was carried out based on actual ship projects, with the clear goal of replacing imported products. Supported by national major special projects, domestic research and development teams set the core technical targets that the propeller efficiency shall not be lower than that of foreign designs and the weight indicators shall not exceed those of foreign schemes, and launched systematic technical research. During the research and development process, the team conducted simulation calculations and parameter optimization one by one on key parameters of large LNG carrier propellers including blade number, diameter, disc area ratio, skew angle, rake, blade section profile and radial load. It systematically sorted out the influence rules of each parameter on ship propulsion efficiency and excitation force, laying a scientific foundation for the preliminary scheme design.
During the basic scheme design phase, the core problem encountered by the R&D team was the stability of back-blade cavitation. Cavitation is an inevitable physical phenomenon generated when a propeller rotates at high speed. Unstable cavitation will trigger severe vibration and noise, which not only impair navigation comfort but also cause corrosion damage to the propeller and hull structures. Such risks are even more pronounced for LNG carriers. After repeated simulation tests, the R&D team effectively improved the stability of back-blade cavitation by optimizing the chordwise load distribution, resolved this pivotal problem that had plagued the design work, and finalized a design scheme with independent intellectual property rights.
Once the design scheme is finalized, challenges emerge in the manufacturing phase. Propellers for large-scale LNG carriers boast enormous dimensions. Take the propeller of China’s first independently developed and delivered 174,000-cubic-meter LNG carrier as an example: the diameter of a single propeller measures 8.4 meters. The propeller for the subsequently awarded 271,000-cubic-meter LNG carrier features an even larger single diameter of 8.6 meters, with each propeller weighing over 33 tons.
Propellers of such colossal sizes impose extremely stringent requirements on casting and machining precision. Classification society standards mandate that the finished weight tolerance between the two propellers be kept within ±2%, yet the R&D team set an even higher benchmark for themselves. Through continuous process optimization, the finished weight deviation between the two propellers of China’s first domestically developed twin-skeg propeller set for large LNG carriers stands at merely 0.06%, far exceeding the tolerance stipulated by classification societies. Its manufacturing precision has attained the top S grade, demonstrating China’s robust capabilities in the manufacture of high-end marine equipment.
First independent delivery: Breakthrough in the propeller for the 174,000 cubic meter LNG carrier
In May 2024, Dalian Marine Propeller Co., Ltd., affiliated with Dalian Corporation of China State Shipbuilding Corporation Limited, successfully delivered the twin-skeg propeller independently developed, designed and manufactured for 174,000-cubic-meter LNG carriers. This marked China’s first full delivery of a wholly self-designed and manufactured complete propeller for large LNG carriers, representing a milestone breakthrough in China’s independent research and development of propellers for large LNG ships. This propeller is an inward-rotating twin-skeg propeller perfectly tailored to the hull lines and power requirements of 174,000-cubic-meter LNG carriers, with all technical indicators meeting or even exceeding design expectations.
The delivered propeller boasts precision indicators far exceeding industrial benchmarks, alongside outstanding performance in propulsion efficiency and excitation force control. Following the completion of its design and fabrication, the R&D team carried out comprehensive model tests and sea trial verifications on actual vessels. Sea trial results demonstrated that the independently designed propeller scheme delivers excellent performance in propulsion efficiency, excitation force regulation and weight management. The propeller operates steadily, the vessel’s speed fully complies with design specifications, and it completely satisfies the operational demands of large LNG carriers, capable of replacing imported equivalents.
The significance of this independently delivered propeller extends far beyond supplying a qualified product; it has validated China’s end-to-end independent R&D capacity covering the entire process from design to manufacturing and broken the monopoly held by overseas enterprises over the large LNG carrier propeller market. Prior to this breakthrough, propellers for every large LNG vessel built domestically had to be imported from abroad, incurring high procurement costs, lengthy delivery lead times and the risk of technological bottlenecks imposed by foreign parties. The successful delivery of this first domestically produced unit enables China to achieve full independent controllability over key core components for large LNG carrier construction, laying a solid foundation for its large-scale industrial application in the future.
Market Makes Another Breakthrough: Won the Bid for the World's Largest 271,000 Cubic Meter LNG Ship Propeller Order
Following the successful delivery of the first independently developed product, China's achievements in the self-developed propellers for large-scale LNG carriers have rapidly gained market recognition. In June 2026, Dalian Marine Propeller Works, a subsidiary of China Heavy Industry Corporation under China State Shipbuilding Corporation, won the bid for propeller orders for 18 units of the world's largest 271,000-cubic-meter LNG carriers, with the order value exceeding 100 million yuan. This marks another major breakthrough for Dalian Marine Propeller Works in the large LNG carrier propeller market after it manufactured propellers for 174,000-cubic-meter LNG carriers, verifying that domestically produced large LNG carrier propellers are now capable of large-scale market competition.
The 271,000-cubic-meter LNG carriers awarded in this bid boast the world's largest cargo tank capacity to date, imposing stricter requirements on propellers compared with the 174,000-cubic-meter vessel type. Each propeller for this vessel has a diameter of 8.6 meters with four blades and weighs over 33 tons, and is required to meet the highest S-level manufacturing precision standard. Faced with this order featuring larger dimensions and more stringent specifications, Dalian Marine Propeller Works has established mature design and manufacturing capabilities to deliver qualified products on schedule in accordance with client requirements, backed by experience and technological foundations accumulated through previous research breakthroughs.
The acquisition of this bulk order signifies that domestically produced large LNG carrier propellers have officially entered the industrialization phase, shifting from technological breakthroughs to commercial application. It took merely two years to progress from the delivery of the first set of propellers to securing the bulk order for 18 units. Such rapid development fully demonstrates the value of independent innovation and reflects the global shipbuilding industry's recognition of Chinese technology and manufacturing. Upon the delivery of this batch of orders, China's global market share in large LNG carrier propellers will increase markedly, further consolidating China’s position as the world’s top shipbuilding natio-n.
