1. Project Background

An offshore Liquefied Petroleum Gas (LPG) tanker has long adopted an aging mechanical gyrocompass as its core navigation device. Years of operation have exposed multiple inherent drawbacks of the original equipment:

• The mechanical gyro requires lengthy warm-up time and is prone to heading drift errors caused by vessel rolling and ocean swells, resulting in unstable heading output;
• It can only output single heading data, lacking roll, pitch, heave and rate-of-turn attitude parameters, leaving the crew without hull attitude reference during cargo loading/unloading and navigation in narrow offshore waterways;
• The complete mechanical gyro assembly features a bulky main unit together with supporting control and drive units, which occupy most space in the navigation compartment with complicated wiring. Regular calibration and maintenance involve cumbersome procedures;
• Worn mechanical components require frequent replacement with long lead times for spare parts. Frequent dockside maintenance drives up operating costs and fails to meet the high-reliability navigation supervision standards for hazardous chemical carriers.

To improve navigation accuracy, simplify equipment maintenance and optimize cabin space layout, the shipowner selected the split-type fiber optic gyrocompass system developed by Qingdao hotech to fully replace the original mechanical gyro navigation equipment and realize digital upgrading of the vessel’s navigation system.

2. System Composition 

Adopting a split modular design, Qingdao hotech fiber optic gyrocompass consists of four coordinated units tailored for the confined, enclosed cabin environment of hazardous chemical tankers:

Main Unit – Fiber Optic Gyro Sensing Main Unit (Blue Octagonal Enclosure)

The core measurement component integrated with high-precision fiber optic gyro sensitive elements. The printed directional arrow precisely marks the vessel’s fore-aft reference line. Its lightweight and compact design enables flexible installation inside the navigation equipment compartment, eliminating the space limitation imposed by the heavy shock-absorbing base of traditional mechanical gyros. It outputs real-time six-degree-of-freedom (6-DOF) attitude data including heading, roll, pitch, heave and rate of turn, fully addressing the functional limitation of mechanical gyros that only provide heading information.

Power Unit / Line Unit – Signal Drive & Power Control Cabinets (Olive Green Enclosures)

Supporting signal transceiving and line compensation modules that are compatible with the vessel’s original navigation wiring without large-scale cabin circuit renovation. They deliver stable transmission of attitude data to steering gears, GPS, voyage data recorders, radar and other onboard devices with strong anti-interference performance, adapting to the electromagnetic environment generated by high-power motors and pumps on LPG tankers.

Independent Stabilized Power Supply Unit (Black Enclosure)

A dedicated 22V isolated stabilized power supply that independently powers the entire fiber optic gyrocompass system. It counteracts onboard grid voltage fluctuations and power surges during equipment startup/shutdown, ensuring uninterrupted navigation data output during port entry/exit and cargo handling operations, complying with explosion-proof power supply specifications for LPG carriers.

Monitor Unit – Wheelhouse Touch Display Terminal

A compact touchscreen mounted on the edge of the wheelhouse console without occupying core navigation operation space. It supports one-click switching between Chinese and English interfaces, visually displaying full attitude parameters, equipment operating status and fault alarms in real time. Crews can conveniently complete parameter calibration and system self-checks, with a far lower operation threshold compared to the complex adjustment procedures of old mechanical gyros.

3. Core Application Advantages vs. Traditional Mechanical Gyrocompasses

1）High Precision & Low Drift to Greatly Enhance Navigation Safety of Hazardous Chemical Carriers

Traditional liquid-floated mechanical gyros suffer severe heading drift during long-distance voyages due to temperature changes and sea turbulence. Qingdao hotech fiber optic gyro contains no rotating mechanical parts, resulting in zero abrasion and no mandatory warm-up period — stable heading and full attitude data are available immediately after startup. When navigating in ports, narrow channels and anchorages, LPG tanker crews can predict hull sway via roll and pitch data to avoid navigation risks triggered by liquid sloshing inside cargo tanks, satisfying stringent safety standards for hazardous chemical vessels.

2）Flexible Split Layout to Maximize Cabin Space Utilization

Traditional mechanical gyrocompasses occupy the majority of navigation compartment space with their bulky main bodies, shock-absorbing bases and multiple control boxes. The compact sensing main unit and power modules of hotech fiber optic gyro can be centrally installed in idle areas of the equipment compartment, with only a miniature touchscreen placed in the wheelhouse. This frees up substantial cabin space for additional fire-fighting and monitoring equipment upgrades. The whole set can be installed, calibrated and commissioned within a short dock call without structural modification to the vessel hull.

3）Eliminated Frequent Calibration to Cut Vessel Maintenance Costs

Mechanical gyrocompasses require regular disassembly for drift correction and latitude-speed error compensation with complicated maintenance workflows. Featuring a solid-state wear-free structure, hotech fiber optic gyrocompass supports automatic background error compensation without frequent manual adjustment during long sea voyages. It reduces dry-docking and dockside maintenance frequency, cutting spare part procurement and labor costs for LPG tankers operating across multiple sea areas long-term.

4）Full Attitude Data Output for Compatibility with Modern Intelligent Vessel Systems

While traditional mechanical gyros only output single heading signals, hotech fiber optic gyrocompass transmits complete 6-DOF attitude messages compliant with standard NMEA marine protocols. It can interface with auxiliary dynamic positioning systems, navigation situation monitoring equipment and cargo tank attitude safety monitoring devices, enabling integrated intelligent monitoring of vessel navigation and liquid cargo status for LPG carriers.

5）Bilingual Visual Terminal for Multi-crew Operation Scenarios

The wheelhouse touch terminal is preloaded with Chinese and English operation interfaces for quick operation by both domestic and foreign seafarers. Clear text labels for data, alarms and setting menus deliver a more intuitive human-machine interaction than analog dial readings on mechanical gyros, minimizing human interpretation errors.

4. Project Outcomes

After completing the retrofitting replacement project, the LPG tanker achieved comprehensive upgrading of its navigation system:

1. Navigation accuracy is drastically improved with significantly reduced heading drift errors, raising safety standards for navigation in narrow channels and offshore waters to meet regulatory requirements for hazardous chemical carriers;
2. Space is released in the equipment compartment with a neat, organized split installation layout and streamlined wiring, complying with explosion-proof and tidiness management codes for LPG carrier cabins;
3. Daily maintenance workload is largely reduced by removing mandatory frequent mechanical calibration procedures, effectively cutting overall vessel operating costs;
4. Synchronized output of full attitude data links all onboard intelligent monitoring devices, accelerating digital and intelligent transformation of the vessel’s navigation system.

5. Project Summary

Boasting core strengths including zero mechanical wear, high-precision stable heading output, space-saving split layout and low maintenance requirements, the split-type fiber optic gyrocompass from Qingdao hotech delivers a proven mature solution for replacing aging mechanical gyrocompasses on LPG tankers. Perfectly adapting to the special navigation and cabin operating conditions of hazardous chemical carriers, this product provides a reliable domestic alternative for navigation system renewal of domestic LPG and LNG transport vessels.