Marine hydraulic systems used for deck winches, cranes, hatch covers and steering gears operate under unique structural constraints.
Long piping layouts and limited pump room space make system stability and noise control critical design considerations.

Industry Background

Two common challenges appear in most marine hydraulic systems:

Long piping with multiple bends amplifies flow pulsation into vibration and noise throughout the system

Pump room space is limited, while the number of hydraulic circuits continues to increase, making layout, maintenance and noise control more difficult

These issues directly affect onboard comfort, equipment reliability and service accessibility.

Technical Challenge

Traditional hydraulic systems often use external gear pumps or piston pumps as the main power source.

In long piping environments, these solutions tend to show:

Higher flow and pressure pulsation, leading to pipe vibration and structural resonance

Difficulty in coordinating multiple circuits sharing a single pump

Increased system complexity and maintenance difficulty as more functions are added

These limitations highlight the need for a more stable and compact hydraulic architecture.

Solution Approach: FG Internal Gear Pumps with FG21 Dual Pump Configuration

To address these challenges, modern marine hydraulic platforms are increasingly adopting FG series internal gear pumps combined with FG21 dual pump configurations.

Key Technical Characteristics

Rated pressure up to 31.5 MPa
Maximum pressure up to 35 MPa
Speed range from 200 to 3000 r/min

These parameters support both high-load deck machinery and flexible control requirements.

Structural Advantages

Internal gear design provides low flow and pressure pulsation, reducing vibration transmission in long piping systems

Stable output improves coordination between multiple hydraulic functions

Wide speed range allows efficient operation under varying load conditions

Compact Multi-Circuit Integration

FG21 dual pumps integrate two circuits on a single shaft driven by one motor:

Main circuit supplied by a medium-to-large displacement FG2 pump

Auxiliary circuits supplied by a smaller FG1 pump

This configuration reduces system footprint while maintaining functional separation.

Typical Application Configuration

Engineers commonly adopt the following structure:

FG2 (approximately 80–125 mL/r) for main circuits powering winches, cranes and hatch covers

FG1 (25–40 mL/r) for auxiliary functions such as braking, locking and secondary actuators

Compared with multi-pump layouts, this approach reduces the number of components and simplifies system architecture.

Performance Improvements in Operation

After implementing FG / FG21 systems, several improvements are observed:

Reduced vibration and noise in long piping systems

Smoother start/stop behavior in winches and controlled movement in hatch covers

More stable system response during multi-circuit operation

Reduced number of maintenance points in the pump room

Increased available space for inspection and service work

Engineering Value

FG / FG21 solutions address not only individual component performance, but overall system architecture.

They provide:

Low-pulsation hydraulic output for long piping environments

Compact multi-circuit integration for space-limited pump rooms

Improved coordination between multiple hydraulic functions

Simplified maintenance and system expansion

Summary

In marine hydraulic systems, the main challenge is not only meeting pressure requirements, but controlling pulsation, vibration and system complexity within constrained space.

FG / FG21 internal gear pump solutions enable:

Reduced noise and vibration

More efficient use of pump room space

Improved system stability and control

Simplified maintenance and future scalability

This approach creates a more balanced and reliable hydraulic foundation for modern marine deck equipment.