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Overview
The Twin Disc MG520 is a reverse reduction deep case marine transmission designed to deliver outstanding performance in demanding commercial marine applications. Suitable for tugboats, dredgers, large workboats, offshore support vessels, and other high-power vessels, the MG520 offers a robust design, superior torque handling, and reliability under continuous and intermittent duty cycles. It supports engines delivering 531 to 718 kW (712 to 962 hp), ensuring efficient power transfer and long-term durability.
Twin Disc MG520 Ratios for Sale
Our rebuilt Twin Disc MG520 marine transmissions are available in a range of gear ratios, each meticulously rebuilt and tested for reliability and performance. These configurations offer vessel operators the flexibility to match propulsion systems to specific operational demands, ensuring optimal efficiency, control, and durability in challenging marine environments.
- Twin Disc MG520 marine transmission ratio 4.5:1 for sale
Featuring a deep case design for enhanced durability and performance, the 4.5:1 ratio is perfect for vessels requiring a balance of torque and maneuverability. It is ideally suited for fishing boats, pilot craft, survey vessels, and multipurpose commercial ships operating in environments where reliable propulsion and adaptable control are essential. This ratio ensures smooth acceleration, responsive handling, and efficient fuel consumption under variable load conditions, making it a versatile choice for operators managing diverse operational profiles.
- Twin Disc MG520 marine transmission ratio 5.0:1 for sale
The 5.0:1 ratio, with its deep case configuration, delivers increased torque output and precise control, making it ideal for tugs, trawlers, dredgers, and utility vessels operating under heavy load or in rough sea conditions. This setup provides the additional thrust required for towing, pushing, and navigating through adverse weather or challenging waterways. Its design optimizes low-speed maneuvering, enabling safe and confident operation in congested ports, high-drag operations, or during tight turns and complex docking procedures.
- Twin Disc MG520 marine transmission ratio 6.0:1 for sale
Built for the most demanding operational environments, the 6.0:1 ratio offers exceptional pulling power and precise low-speed control. It is the ideal choice for offshore support vessels, dredgers, cargo ships, and vessels performing high-drag or constant-load operations. Operators benefit from enhanced fuel efficiency during extended working periods, reduced wear and tear on engine components, and the ability to maintain steady propulsion and precise positioning even under challenging conditions such as high currents or confined operational zones.
- Twin Disc MG520 marine transmission ratio 7.0:1 for sale
Engineered for maximum torque and maneuverability, the 7.0:1 ratio is optimized for large-scale commercial vessels, high-capacity tugs, and offshore support ships. Its deep case construction is designed to handle heavy loads and sustained high torque without compromising performance. This configuration enables operators to execute complex maneuvers, such as docking in restricted areas or managing precise towing operations, with confidence and ease. It also ensures consistent propulsion and stability in rough seas or when performing dynamic positioning tasks.
- Twin Disc MG520 marine transmission ratio 7.5:1 for sale
As the highest available ratio for the MG520, the 7.5:1 configuration provides exceptional pulling power, precise low-speed control, and unmatched reliability. It is the go-to choice for tugboats, large workboats, dredging vessels, and vessels operating under extreme load conditions or within tight harbor environments. This ratio’s superior torque capacity ensures steady propulsion and safe maneuvering, even in complex operations involving heavy towing, pushing, or sustained positioning. Operators can trust the 7.5:1 ratio to deliver maximum performance and control in the toughest marine scenarios.
Each rebuilt MG520 transmission from Diesel Pro Power is quality-assured, rigorously tested, and backed by a refundable core deposit, ensuring confidence in performance and reliability. Our fast global shipping and deep technical expertise help keep your vessel running strong and minimize downtime.
Specifications, Dimensions, and Options
The Twin Disc MG520 transmission is designed with reliability and versatility in mind, incorporating a deep case construction with a single helical gear set. This robust design ensures exceptional performance under continuous and intermittent duty cycles.
Specifications:
- Power Rating: 531 to 718 kW (712 to 962 hp), depending on gear ratio and service classification.
- Design: Reverse reduction, deep case construction with single reduction and single helical gear design.
- SAE Housing: Typically SAE #1 standard housing.
- Dry Weight: Approximately 1656 kg (3652 lbs).
- Maximum Input Speed: Up to 2500 RPM.
- Reduction Ratios Available: 4.5:1, 5.0:1, 6.0:1, 7.0:1, 7.5:1.
Dimensions:
- Length: Approximately 1,067 mm (42.0 in)
- Width: Approximately 762 mm (30.0 in)
- Height: Approximately 1,092 mm (43.0 in)
- Torque Rating: Up to 592 Nm (436 ft-lb) per input shaft.
Options:
- 12V or 24V electric selector valves for customized control systems.
- Manual or electric trolling valves for precise low-speed adjustments.
- Electric or mechanical control systems tailored to vessel specifications.
- Fresh water or raw water heat exchanger kits to maintain optimal operating temperatures.
- Companion flange and output couplings for flexible integration.
- Live PTO options: SAE 6/4, SAE 4/4, and hydraulic pump drive flanges.
- Output shaft adaptors for various vessel configurations.
- Oil pressure and temperature gauges to monitor system performance.
- Optional oil cooling systems for extended and continuous duty cycles.
Key Features and Benefits
- Vertical Offset Design with deep case construction for exceptional durability.
- Oil-Controlled Clutch Engagement for smooth gear transitions under load.
- Carburized, Hardened, and Ground Gears for reduced maintenance and extended service life.
- Emergency Come-Home Capability for limited propulsion during clutch failure.
- Reverse Reduction Capability for versatility in dual-shaft and reverse propulsion systems.
- Robust Construction for harsh marine environments and demanding operational profiles.
Engine Compatibility For The Twin Disc MG520
The Twin Disc MG520 is engineered to pair effectively with high-output diesel engines delivering up to 962 horsepower, making it an exceptional choice for a wide array of commercial and industrial marine applications. This robust marine transmission excels in handling high torque loads and continuous operation, providing reliable propulsion for vessels that demand precision, power, and resilience. Below is a detailed exploration of compatible engines and how they align with the MG520’s performance capabilities.
Caterpillar Engines
Caterpillar engines are renowned for their durability and consistent performance in marine applications, and several models are ideally suited for pairing with the MG520:
- C15: This engine delivers reliable power in the 400–850 hp range, offering a balance of torque and efficiency for vessels such as workboats, tugs, and trawlers. The C15’s high torque at lower RPMs complements the MG520’s capability to handle high thrust requirements.
- C18: Delivering up to 1000 hp, the C18 is a staple in the marine industry for offshore support vessels, large workboats, and tugs. Its exceptional torque output and reliability make it a natural match for the MG520, particularly in continuous or medium-duty operations.
- 3500 Series: Engines like the C32 and C3512 offer robust power (well over 1000 hp) but can be configured in de-rated versions or with torque-limiting measures to work seamlessly with the MG520. These engines are common in dredgers, supply vessels, and high-load commercial craft.
Cummins Engines
Cummins engines are celebrated for their reliability and adaptability in commercial marine environments:
- QSK19: Producing 500–800 hp, the QSK19 is widely used in supply vessels, trawlers, and high-power workboats, providing the torque and control needed for demanding operations.
- KTA38: With outputs ranging from 750 to 1000 hp, this engine is well-suited for large commercial vessels, dredgers, and offshore support vessels. Its robust performance under high-load conditions pairs seamlessly with the MG520’s deep case design.
- QSK38: Offering 850–1100 hp, the QSK38 can be configured to match the MG520’s capacity, making it an excellent choice for vessels requiring high power and torque for continuous or heavy-duty operations.
Detroit Diesel Engines
Detroit Diesel engines have long been a trusted choice in the marine industry:
- 12V92TA: Delivering 525–750 hp, this engine is commonly found in tugs, workboats, and fishing vessels where reliable power and efficiency are critical.
- 16V92TA: With up to 850 hp, the 16V92TA excels in heavy-duty marine applications such as large trawlers and offshore supply vessels. Its high torque output and resilience complement the MG520’s design.
MTU Engines
MTU engines are synonymous with high-performance propulsion systems:
- Series 2000: Engines in this range deliver 800–1200 hp, but can be configured within the MG520’s capacity. They are ideal for offshore supply vessels, patrol boats, and ferries requiring precise control and high thrust.
- Series 4000: Designed for continuous heavy-duty applications, these engines produce high horsepower and torque but can be de-rated or paired with the MG520 for specialized marine installations.
John Deere, MAN, Scania, and Volvo Penta
Several high-output diesel engines from these manufacturers also align with the MG520’s torque and power requirements:
- John Deere 6135AFM85: Up to 750 hp, ideal for commercial fishing boats, pilot craft, and mid-sized workboats.
- MAN D2868 LE433: Delivering 800–1000 hp, this engine fits well with high-demand vessels requiring durability and power.
- Scania DI16 076M: Produces up to 800 hp, a solid match for tugs, supply boats, and multipurpose vessels.
- Volvo Penta D13 MH: Offers 600–800 hp, providing reliability and efficiency for a range of commercial applications.
Why Engine Compatibility Matters
Selecting the correct engine to pair with the MG520 is crucial for optimizing propulsion efficiency, reliability, and fuel economy. Compatibility ensures:
- Proper torque matching, reducing drivetrain stress and wear.
- Optimal fuel efficiency, especially in continuous or high-load operations.
- Seamless integration with SAE housing standards, including coupling and mounting systems.
- Enhanced durability, extending the service life of both the engine and transmission.
Service Classifications
Understanding the correct service classification is vital for determining operational expectations, maintenance schedules, and performance benchmarks for the MG520:
- Continuous Duty: This classification is for vessels such as tugs, supply boats, and ferries operating at full power for extended periods. Continuous duty places the greatest demands on the transmission and engine, requiring rigorous maintenance, frequent oil changes, and monitoring of wear components to ensure long-term reliability.
- Medium Duty: This category applies to vessels operating up to 4000 hours/year at up to 80% load, including workboats, trawlers, and patrol vessels. Medium duty combines periods of high load with intervals of reduced power, balancing performance with fuel economy. Maintenance intervals may be extended compared to continuous duty, but routine inspections remain critical.
- Intermediate Duty: Vessels operating up to 2000 hours/year at high power with intermittent load reduction, such as pilot vessels, commercial fishing boats, and multipurpose workboats, fall under this classification. Intermediate duty offers more flexibility in maintenance but requires attention to signs of wear and proper operation during high-demand cycles.
- Customized Configurations: For vessels with unique operational profiles, including mixed-duty cycles, complex towing operations, or specialized offshore tasks, consult with marine engineering specialists to determine the most suitable service classification and configuration for the MG520 transmission.
Important Notice
The performance data and product information provided are intended as general guidelines. Diesel Pro Power assumes no responsibility for system-related issues, failures, or damage resulting from improper selection, installation, or maintenance of rebuilt transmissions. It is the responsibility of the purchaser and installer to ensure proper integration with the vessel’s engine and compliance with all safety standards and operational guidelines.
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