I. Ship and Marine Engineering: Bearings in the "Deep Sea Battlefield"

The ocean covers 71% of the Earth's surface, and every ship and platform that supports human maritime activities relies on bearings for their power and movement. Ship and marine engineering bearings are installed in key positions such as the propulsion shaft system, steering gear, deck machinery, and underwater production systems, and they undertake the task of continuous operation in a combined environment of seawater corrosion, heavy load impact, and extreme temperature differences.

 

The global marine engineering bearing market is valued at approximately $905 million in 2025 and is expected to grow to $1628 million in 2032, with a compound annual growth rate of 8.74%. The global ship bearing market size is approximately $1847 million in 2025 and is expected to reach $3055 million in 2035. The Chinese marine sliding bearing market is expected to reach 1.049 billion yuan in 2026. The value of thick-walled sliding bearings for a 174,000 cubic meter LNG transport ship is approximately 10-15 million yuan.

 

In the deep shafts of ocean-going vessels, the failure of a single bearing can mean the delay of the entire route and millions of dollars in maintenance costs. Bearings in the power system of ships perform key functions such as power transmission and shaft support, and their reliability directly affects the navigation safety and operational efficiency of ships. NMT, a Japanese company with over a century of expertise in precision bearings, provides high-reliability and long-life precision bearing solutions for the ship and marine engineering fields using corrosion-resistant materials, precise manufacturing, and system-specific capabilities.

 

II.艉轴轴承： The "Deep Lock Joint" of Ship Power System

The艉轴 bearing is the core supporting component of the ship's shaft system， installed in the stern tube at the stern of the ship， supporting the stern shaft that connects the main engine and the propeller. It operates under low-speed and heavy-load conditions and not only has to withstand the thrust of the propeller and rotational friction but also needs to resist continuous seawater erosion. The lubrication characteristics of the艉轴 bearing directly affect the bearing power consumption and propulsion efficiency.

 

As the tonnage of ships continues to increase， the gravitational force of the艉轴 and the propeller becomes greater， and the艉轴 often undergoes flexure， causing a significant edge load on the艉轴承 and even disrupting the good lubrication state between the bearing and the shaft neck. The misalignment or bending of the ship's shaft system causes an increase in the movement amplitude of the艉轴， and when this amplitude exceeds the gap between the bearing and the shaft neck， it causes collision and friction. Water-lubricated艉 bearings， due to their simple structure and pollution-free characteristics， have become the current development trend and research hotspot.

 

In emerging shipping scenarios such as polar routes， climate change-induced ice loads are transmitted to the艉轴承 through the propeller shaft， posing new assessment requirements for the remaining fatigue life of the bearings.艉 bearing failures will affect the operation of the entire ship and also increase the safety risks of the ship.

 

III. Propulsion Shaft System and Thrust Bearings： The "Power Hub" for Power Transmission

The propulsion shaft system is the core channel for power transmission in ships， responsible for transferring the power from the main engine to the propeller. In this energy transmission chain， thrust bearings， intermediate bearings， and艉轴 bearings each perform their own duties to ensure the stable operation of the propulsion system. Thrust bearings bear the huge axial thrust generated by the propeller and transfer it to the hull； intermediate bearings support the middle section of the long shaft system to prevent excessive sagging of the shaft system.

 

In the design and installation of ship shaft systems， the rational distribution of bearing loads is crucial. The alignment state of the shaft system directly affects the load distribution of each bearing， and an unreasonable load distribution may lead to premature wear or even burnout of the bearings. Special ship types such as large semi-submersible ships， under different working conditions such as full load， ballast， and floating， the deformation of the hull will cause changes in the support position of the shaft system， requiring precise shaft alignment calculations to ensure that the bearing loads are within safe limits. With the implementation of the environmental protection regulations by the International Maritime Organization (IMO), the demand for upgrading the shaft systems of old ships has increased, and the market for retrofits is approximately 15%-20% of the new shipbuilding market. These upgrading projects have higher requirements for the reliability, maintainability, and environmental friendliness of bearings.

 

IV. Deck Machinery and Steering Gear Bearings: The "Power Support" of Ship Operations

Apart from the propulsion system, the deck machinery and steering gear of ships also rely heavily on bearings. Bearings for equipment such as anchor winches, winch reels, cranes, and steering gears need to operate continuously in outdoor, humid, and salt-spray environments. The reliability of these bearings directly affects the efficiency of ship loading and unloading operations and the safety of navigation control.

 

Steering gear bearings bear the huge hydrodynamic loads transmitted from the rudder blades, experiencing intense load changes during ship steering. Deck machinery bearings, on the other hand, endure alternating loads during frequent start-stop and heavy lifting operations. In these scenarios, bearings not only need to be corrosion-resistant but also need to maintain long-term reliable operation under limited maintenance conditions.

 

V. LNG and Low-Temperature Engineering: The Extreme Cold Challenge at -165°C

Liquefied Natural Gas (LNG) carriers are one of the most technologically advanced ship types in the maritime and marine engineering industry. The LNG submersible pump, as the core device of the low-temperature fluid transportation system, needs to operate continuously at -165°C under ultra-low temperature conditions, and its performance directly affects the overall operational efficiency and safety level of the LNG industry chain.

 

In extreme low-temperature environments such as LNG submersible pumps, ordinary bearing steel undergoes a low-temperature brittle transformation, and conventional lubricating grease completely solidifies and fails. Ceramic bearings, as the key components of LNG submersible pumps, have attracted much attention in their application development. The low-temperature bearings adopt a mixed structure of high-nitrogen stainless steel rings and silicon carbide (Si₃N₄) ceramic balls, featuring low-temperature resistance, wear resistance, and corrosion resistance, and can operate stably without external lubrication at temperatures as low as -196°C.

 

The hand-held orders for LNG carriers in China continue to increase, with the domestic Hudong-Zhonghua Shipbuilding Factory holding orders for 57 vessels, scheduled until 2030. The value of the thick-walled sliding bearings for a 174,000 cubic meter LNG carrier is approximately 10-15 million yuan. Currently, the domestic production rate of bearings for high-value-added ship types such as LNG carriers is only about 35%, with the remaining 65% or more occupied by international manufacturers such as Japan's Daihatsu Metal, Germany's Schaeffler, and Sweden's SKF. The delivery cycle of overseas suppliers has been extended to 12-18 months. The space for domestic substitution is huge.

 

VI. Seawater Corrosion and Material Innovation: The Technical Breakthrough of NMT

Seawater corrosion is the most persistent challenge faced by ship bearings. Seawater contains corrosive components such as chloride ions, which continuously erode bearing materials. Traditional bearing steel is prone to rust and stress corrosion cracking in seawater environments. High-performance ceramic bearings do not react with seawater and most corrosive chemicals, and can maintain stable performance even when immersed in seawater for a long time.

 

NMT ship bearings adopt a high-nitrogen stainless steel and silicon carbide ceramic mixed material solution. High-nitrogen stainless steel maintains high strength while having excellent resistance to seawater corrosion; silicon carbide ceramic balls have low density, high hardness, are non-corrosive, and non-conductive, and have unique advantages in seawater environments. For ultra-low temperature scenarios such as LNG, NMT provides a combination of ring materials with special low-temperature toughness treatment and ceramic balls to ensure no brittle fracture or size change in -165°C to -196°C extreme low-temperature environments.

 

In terms of lubrication, NMT provides water lubrication compatible solutions and wide-temperature range self-lubrication solutions, suitable for diverse operating environments from regular sea areas to polar routes and from normal temperatures to ultra-low temperatures.

 

VII. Materials and Technology: The Technical Foundation of NMT Ship Bearings

The reliability of NMT ship bearings is rooted in a profound understanding of material science and precise manufacturing techniques.

Corrosion-resistant material system - NMT employs high-nitrogen stainless steel, silicon nitride ceramics, and other materials resistant to seawater corrosion, maintaining high strength while resisting chloride ion erosion. For ultra-low temperature scenarios such as LNG, the materials undergo special low-temperature toughness treatment to ensure no brittle transformation occurs at -196℃ extreme low temperatures.

 

Precision manufacturing - The raceways undergo ultra-precision grinding, with surface roughness controlled at the nanometer level, ensuring a stable lubricating film is formed by the bearing under heavy load and low-speed conditions. The retainers and sealing structures are optimized for ship conditions, balancing corrosion resistance and low friction.

 

Scenario-based sealing and lubrication - Ship bearings are compatible with various schemes such as water lubrication, oil lubrication, and grease lubrication. NMT provides contact and non-contact sealing structures, effectively blocking the invasion of seawater and impurities, while maintaining the cleanliness and stability of the lubricant.

 

VIII. Customized Services

NMT supports corrosion-resistant material selection, optimization of ultra-low temperature structures, customization of wide temperature ranges for lubrication, and non-standard customization of special structures. From stern shaft bearings to deck machinery bearings, from conventional merchant ships to LNG transport ships, NMT provides precise-matched products and services for every ship and marine engineering application scenario. Mainstream specifications are in stock ready for immediate delivery, installation dimensions follow industry standards, and can be directly replaced with imported similar products. Professional technical teams provide selection and technical support.

 

IX. Value Summary

From stern shaft bearings to propulsion shaft systems, from deck machinery to LNG cryogenic pumps, ship and marine engineering bearings silently support every voyage and operation of global shipping and marine development in the combined environment of seawater corrosion, heavy load impact, and extreme cold temperatures. The global marine engineering bearing market is expanding at a compound annual growth rate of over 8.7%, and the process of domestic substitution for high-value-added ship types is accelerating.

 

NMT's precision bearings for ship and marine engineering are supported by corrosion-resistant materials, precision manufacturing, and scenario-based sealing and lubrication, providing high-reliability and long-life precision transmission solutions for all ship applications such as stern shaft bearings, propulsion shaft systems, deck machinery, and LNG cryogenic pumps. Let every rotation withstand the erosion of seawater, withstand the pressure of deep sea, and endure the tests of extreme cold - whether in the depths of the ocean-going vessels' shaft systems or in the cryogenic pumps of LNG transport ships.