渔船应用案例
Fishing Vessel Application Case
36米沿海单机拖网渔船全套动力推进配置方案

Concise Explanation of Model Selection Logic

Low-speed configuration of the main engine delivers inherent strong torque, preventing engine overload during large-net towing and head-sea operation.Reasons for selecting FADA D300A: Its load capacity fully fits main engines up to 500 HP. The large housing structure resists trawling impact and ensures outstanding long-term durability. The fixed reduction ratio of 4.0 slows the propeller shaft down to 375 rpm, which maximizes the low-speed high-thrust advantage of the ducted propeller.Thickened 42CrMoA oil-lubricated shafting matches alternating high-power loads, adapting to coastal high salt-fog environments for long-term stable operation.4-blade CU3 ducted propeller balances a free running speed of 12.5 knots and powerful trawling traction, fully meeting the core operation demands of fishing vessels.

I.Mai Engine(Fixed Parameters)


Yuchai YC6T450L-C28

450 horsepower (330 kW), rated speed: 1500 r/min

This low-speed high-torque engine is suitable for continuous heavy-load towing of trawlers. It delivers abundant power reserve for offshore rough sea conditions and large fishing net operation.


II. FADA D300 Gearbox

Transmission load capacity verification: Under the reduction ratio i=4.0, the load factor reaches 0.257 kW/rpm, with a rated bearing capacity of 385.5 kW, higher than the engine’s continuous power of 330 kW. Sufficient safety margin is reserved for heavy-load operation and frequent astern impact.Propeller shaft output speed = 1500 ÷ 4.0 = 375 r/min.Advantages: Large housing modulus delivers strong torsion and impact resistance, perfectly matching high-intensity fishing working conditions of fishing vessels; spare parts are universally available nationwide for convenient maintenance and repair.

Professional Glossary

III.SternShaftSystem(Heavy-Duty Standard for Coastal Vessels)

Material: Integrally forged alloy steel 42CrMoA with one-piece forged flange. Journal surface adopts high-frequency quenching to resist alternating torque and seawater corrosion.Shaft Diameter: Φ135 mm, compatible with power output up to 500 HP to eliminate resonance under heavy load.Total Shaft Length: 3.8 m, split flange design for easy disassembly and overhaul during dock repair.Stern Tube Lubrication: Closed oil lubrication system (white metal bearing shells + double-layer seawater-resistant seals), mandatory configuration for coastal ships. It isolates seawater and sediment, reduces sleeve abrasion, and extends maintenance interval to 12–18 months.

IV. Ducted Propeller (Special for Trawling Efficiency Improvement)

Blades: 4-blade CU3 nickel-aluminum bronze propeller blades, anti-cavitation and corrosion-resistant, not easy to break when scraping against reefs. Equipped with wear-resistant and anti-corrosion duct, the thrust during trawling is increased by 15%~25%, and the risk of fishing net entanglement is reduced.Dimensions: Diameter D=1.70m, Pitch P=1.56m, Pitch Ratio=0.92Matching Performance: The full-load free running speed stably reaches 12.5 knots. Low pitch design focuses on low-speed traction force to achieve optimal trawling efficiency, with reasonable load to avoid engine overload.
50米沿海二类航区客船
50-meter passenger ship for Coastal Zone Category II
全套动力推进配置方案
Sea Trial Operation and Long-Term Maintenance Suggestions
Conduct full-load ship sea trials. If the main engine fails to reach the rated speed of 2100 rpm, slightly reduce the propeller pitch; if the rotating speed is excessively high, appropriately increase the pitch to achieve precise matching of the engine and propeller.
For daily cruising at 12~13 knots, the main engine operates stably in the low-load range of 1700~1800 rpm, delivering optimal fuel economy and minimizing fatigue loss of the whole engine and shafting system.
The 42CrMoA material features excellent durability. Non-destructive testing (NDT) is only required during dock inspection every two years.
A marine photovoltaic energy storage system can be equipped for berthing at the dock. The auxiliary engine can be shut down during docking to effectively reduce diesel consumption.

I.Main Engine (Fixed Parameters)

Weichai WP12C450-21 Marine Diesel Engine
Single unit power: 450 HP / 331 kW, rated speed: 2100 r/min; total power for twin engines: 900 HP
Advantages: Abundant power reserve for head-on navigation in heavy stormy seas and overload passenger carrying during holidays.
It maintains the designed speed of 14 knots stably under full-load condition.

II. Advance 300 Original Gearbox

Matching reduction ratio: 3.5
Propeller shaft output speed = 2100 ÷ 3.5 = 600 r/min
The Advance 300 is a mass-produced general model with easily accessible spare parts and convenient maintenance at shipyards.It provides sufficient torque margin for long-term frequent reversing and start-stop operating conditions.It precisely controls rotating speed within the high-efficiency range, avoiding high-speed cavitation and hull vibration issues.

III. Stern Shaft System (Heavy-Duty Standard for Coastal Vessels)

Material Advantages

Adopt integrally quenched and tempered alloy steel 42CrMoA. It boasts excellent hardenability, fatigue resistance, seawater corrosion resistance and alternating torsion resistance. No microcracks will easily form during long-term high-frequency offshore operation, perfectly fitting the year-round continuous operation of passenger ships.The flange is integrally forged to eliminate defects caused by welding stress.

Shaft Diameter (Professional Torque Verification)

Outer diameter of stern shaft: Φ120 mmIntermediate transmission shaft diameter: Φ110 mm
Its strength fully covers the peak torque under full load of 450 HP, effectively avoiding resonance and bending deformation, and meets the acceptance standards of classification societies.

Shafting Length

Total length of single-line shafting: 4.9~5.2 m. Split flange design enables easy disassembly and maintenance during dock repair. Cutting length can be fine-tuned on site according to the actual distance from the end of engine room to stern post.

Stern Tube Lubrication (Mandatory Standard Configuration for Coastal Vessels)

Closed oil-lubricated stern tube, equipped with white metal bearing shells + double-layer fluororubber seawater-resistant sealing components with fully enclosed engine oil circulation system.It completely blocks seawater from invading the shaft sleeve to minimize journal abrasion, with a maintenance interval of 12~18 months, perfectly protecting the 42CrMoA shaft for long-term stable operation.

IV. Propeller (CU3 Manganese Aluminium Bronze High-Speed Propeller, 5-Blade Special for Passenger Ships)

Material: CU3 Manganese Aluminium Bronze specially used for high-speed propellers. It features strong resistance to cavitation erosion, tiny deformation under high-speed rotation and outstanding seawater corrosion resistance. The blades will not crack easily after slight reef scraping, suitable for high-speed sailing condition at 14 knots.Blade Structure: 5-blade design generates low operation vibration to greatly improve passenger comfort, and delivers excellent propulsion efficiency under heavy load and head sea conditions.Precisely Matched DimensionsPropeller Diameter D=1.18 m, Pitch P=1.1 mStable speed drop rate at full-load speed of 14 knots.
货船应用案例
Application cases of cargo ships
80m×13m×4.6m，满载吃水3.2m，2000吨级内河货船
I. Main Engine (Fixed Parameters)
Main Engine: Zichai 6170 (420 HP / 1500 rpm)
The 6170 series is a classic low-speed heavy-duty marine diesel engine with extremely strong low-speed torque. It is highly adaptable to the harsh working conditions of the upper Yangtze River, including countercurrent navigation, heavy-load climbing, and high resistance in shallow water. Compared with high-speed engines, it features better heavy-load resistance, higher durability and a longer overhaul cycle.
With widespread maintenance outlets and universal spare parts along inland waterways, the engine is easy for crew to repair and maintain on site.
Twin-engine total power reaches 840 HP with sufficient power reserve. It stably supports a full-load speed of 12 knots and avoids overload during frequent start-stop and steering operations in fleet formation navigation.

II. FADA D300A Marine Gearbox

D300A is a heavy-duty large-housing gearbox, whose load capacity fully covers single 420 HP engine. It reserves ample safety margin for frequent astern operation and impact working conditions.Speed conversion calculation: 1500 ÷ 4 = 375 r/min. It amplifies output torque to greatly boost the vessel’s towing force against upstream currents, specially optimized for heavy-load upstream navigation on upper Yangtze River.The large reduction ratio lowers propeller shaft speed, reduces cavitation damage to propeller blades and extends the service life of propellers.

III. Stern Shaft System

Forged steel 42CrMoA is adopted as the material with outstanding torsion resistance and fatigue resistance. It can withstand alternating heavy torque loads without fracture under long-term heavy-load operation. The shaft diameter is Φ145 mm with sufficient strength margin to eliminate resonance and deformation.Water-lubricated stern shaft is selected for inland freshwater vessels, featuring simple structure and low later maintenance cost.The shaft total length is measured as 5m on site, which enables convenient disassembly and overhaul during dock repair.
IV. 304 Stainless Steel Propeller
Specifications: 4-blade propeller, diameter 1.82 m, pitch 1.43 m.
The propeller shaft speed is reduced to 375 r/min. A larger pitch is adopted to compensate for the speed loss caused by low rotating speed, ensuring a stable full-load sailing speed of 12 knots. The 4-blade design effectively reduces operating vibration and delivers higher propulsion efficiency under heavy-load conditions compared with 3-blade propellers, enabling smoother navigation for cargo-loaded vessels.
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