TECHNICAL SPECIFICATION • MARINE GYROCOMPASS
TOKYO KEIKI (TOKIMEC)
IMO A.424(XI) • ISO 8728 COMPLIANT
The Tokyo Keiki TG8100 Gyro Compass represents Tokyo Keiki’s flagship marine heading sensor engineered for commercial merchant vessels. Designed on the proven legacy of the TG-6000 and TG-8000 series installed across tens of thousands of ships worldwide, the TG-8100 integrates advanced microprocessor servo tracking, an oil-damped torsion-wire suspension system, and full Bridge Alert Management System (BAMS) compliance.
Up to 75°/sec
< 4 Hours (Typ. 3h)
Less than ±0.3°
Tokyo Keiki TG-8100 Gyro Compass
Next-Generation Heading Accuracy & Reliability
Built as the direct successor to the legacy TG-6000 and TG-8000 models, the TG-8100 provides enhanced follow-up dynamics, lower power consumption, and seamless connectivity to radar, ECDIS, autopilot, and voyage data recorders (VDR).
- Conformity: IMO A.424(XI), ISO 8728, Wheelmark MED, USCG approved
- Configuration: Type S (Single Gyro, ~16 kg) and Type D (Dual Gyro, ~23 kg) Control Units
- High-Speed Counterpart: Pairs with the TG-8600 for High-Speed Craft up to 70 knots
- Life Cycle Support: Seanav Marine provides complete overhaul, genuine sensitive elements, exchange PCBs, and port service
1. System Architecture & Major Assemblies
The Tokyo Keiki TG-8100 system architecture separates mechanical sensing from bridge display and power conditioning, ensuring optimal vibration isolation and simplified bridge layout:
- Master Compass Unit (MGC): Houses the precision gimbal ring assembly, container/damping vessel, step-transmitting follow-up motor, optical pickup tracking sensor, and the suspended sensitive gyrosphere element. The unit can be mounted in the bridge console, steering stand, or a dedicated gyro room.
- Gyro Control Unit (GCU): Available in Type S (Single Gyro configuration, approx. 16 kg) or Type D (Dual Gyro configuration, approx. 23 kg). It houses the system dual-redundant power supplies, master CPU controller boards, rotor inverter drives, and signal distribution amplifiers.
- Operation & Display Panel (DPU / PNU): Offered in standard 1-DIN console format with high-visibility 7-segment LED heading readout, or 2-DIN color LCD console (prepared for dual setups integrated with optical or fiber optic gyro TF-1000/900). Features dedicated Bridge Alert Management (BAM) indicators for Caution (C), Warning (W), and Alarm (A).
- Transmission & Heading Repeater Network: Supports high-speed serial IEC 61162-2 / NMEA 0183 channels (
$HEHDT,$THS,$HEROT), classic step-by-step repeater drives, and analog Rate-of-Turn outputs.
2. Printed Circuit Board (PCB / PWB) Assemblies & Field Replaceable Units
For onboard technical troubleshooting, board-swapping, and survey maintenance, Tokyo Keiki specifies dedicated 8-to-10-digit part numbers across all core electronic modules:
| PCB / Board Designation | Module Function | Part / Assembly Number | Technical Notes |
|---|---|---|---|
| SCC PWB | System / Servo Control Computer | 10189521- / 10189661- | Master CPU board; requires FW v2.21+ on newer units |
| PWB_LPANEL | Local Display Panel Controller | 10189665- / 10189689- | Drives 7-segment LED display and LCD operation keypads |
| 2nd Servo Amp PCB | Follow-up Servo Amplifier Circuit | 102290450 | Drives azimuth follow-up servo motor at up to 75°/sec |
| Inverter PWB / Ass’y | Rotor Static Inverter Drive | 1018xxxx / INV-OCT | Drives the 3-phase high-frequency rotor motor in gyrosphere |
| Step Amplifier PCB | Output Distribution / Repeater Driver | Step Amp Ass’y | Drives classic stepper gyro repeaters and autopilot sync |
| GTERM-A PWB | Master Terminal & Junction Board | Control Unit Interface | Power distribution, contact alarms, and terminal fuses |
| C-TERM / ESCC PWB | Serial Comm Buffer & Interface | Serial (SIFC) / Step (MIFC) | Handles IEC 61162-2, NMEA 0183 & BAMS network lines |
3. Sensitive Element & Mechanical Overhaul Spares
The sensitive element is the core electromechanical heart of the Tokyo Keiki gyrocompass. Suspended in supporting fluid by dual torsion wires, it eliminates mechanical bearing friction, achieving a calculated mean operating life of 35,000 to 50,000 hours:
| Part Description | Tokyo Keiki Part / Type No. | Usage & Overhaul Intervals |
|---|---|---|
| Gyrosphere / Sensitive Element | 10229409 (or L8082SF / LZ047QYSF series) | Core rotor ball suspended in fluid; ~35,000–50,000 hours |
| Supporting / Flotation Liquid | Tokyo Keiki Gyro Fluid Kit | Silicon/mineral damping oil renewal (every 1–2 years) |
| Master Follow-up Belt | Drive Belt (Master azimuth gear) | Replaced during major standard overhaul routines |
| Slip Ring & Brush Block Ass’y | Slip Ring Pick-up Ass’y | Transfer contacts between rotating gimbal and stationary frame |
| Follow-up / Servo Motor | Azimuth Follow-up Motor | Powers the dynamic follow-up gear train and azimuth ring |
| Mercury / Contact Level Ass’y | Leveling Sensor Assembly | Horizontal tilt sensing, meridian settling & damping control |
Standard Overhaul & Annual Kit Consumables
- Packing Gaskets & O-Rings: Master compass container seal rings, oil reservoir sealing gaskets, and fluid change plug washers.
- Filter Element & Desiccant Kit: Air vent breather packing and silica drying bags to prevent condensation build-up inside the casing.
- Illumination Lamps: Part 10004345 (45V 5W, E12 base socket) for analog repeater heads, steering repeaters, and bridge bearing dials.
4. Operating Parameters & Technical Specifications
| Technical Parameter | Tokyo Keiki TG-8100 Specification |
|---|---|
| Application Scope | Standard commercial merchant vessels (≥ 500 GT) |
| Conformity Standards | IMO A.424(XI), ISO 8728, IEC 60945, IEC 61162-2 |
| Follow-Up Tracking Rate | Up to 75°/sec |
| Settling Time | < 4 hours (typically within 3 hours from cold start) |
| Settling Error | Less than ±0.3° |
| Repeatability | ±0.2° |
| Main Power Input | AC 100 / 110 / 115 / 220V (1φ, 50/60 Hz) |
| Emergency Power Input | DC 24V (automatic seamless switchover) |
| Power Consumption | 140 VA (Start-up) / 70 VA (Continuous running) |
| Digital & Analog Interfaces | Serial IEC 61162-2 / Step signals / Rate of Turn (ROT) |
5. Key Operational Features & Bridge Integration
Startup Timer Function
Enables bridge watchstanders to preset cold startup up to 99 hours in advance. Typically set 3–4 hours prior to engine telegraph readiness, the compass automatically stabilizes at true north before departure, completely eliminating pre-sailing delays at berth.
Bridge Alert Management (BAMS)
Fully compliant with IMO MSC.302(87). Pre-configured software and relay handshakes integrate directly into centralized bridge alert consoles, prioritizing status annunciations across Caution (C), Warning (W), and Alarm (A) escalation protocols.
External Heading Sensor Interfacing
Receives serial heading data from external GPS compasses, magnetic compass fluxgates, or secondary gyrocompasses. The system performs automatic discrepancy cross-checking and heading comparison alerts.
Retrofit & Upgrade Path
Direct physical and electrical upgrade path for legacy TG-8000 and TG-6000 systems. Existing bridge wiring, step lines, and repeater conduits can be repurposed with minimal modifications.
6. Frequently Asked Questions (FAQ)
1. What is the difference between the Tokyo Keiki TG-8100 and TG-8600?
The TG-8100 is engineered for standard commercial ships compliant with IMO A.424(XI) and ISO 8728. The TG-8600 is specifically designed for High-Speed Craft (HSC) operating up to 70 knots, certified under IMO A.821(19) and ISO 16328 HSC.
2. How often should the sensitive element (gyrosphere) be serviced or replaced?
The TG-8100 sensitive element (Part 10229409 / L8082SF / LZ047QYSF) features a design life of ~35,000 to 50,000 operational hours. Periodic maintenance requires supporting fluid renewal every 1 to 2 years, with comprehensive sphere overhaul or exchange recommended every 3 to 5 years depending on vessel operating profile.
3. Can the TG-8100 directly replace an older Tokimec TG-6000 or TG-8000?
Yes. The TG-8100 provides backward-compatible mounting footprints, signal interfaces, and step repeater outputs that seamlessly integrate with existing bridge infrastructure, steering gear autopilot systems, and wing repeaters.
4. What should be done if a BAMS Warning or Alarm occurs?
Inspect the code on the DPU/PNU operation display panel. Common alerts include follow-up motor lag, inverter frequency variations, or power supply transfer. Note the displayed alarm code and serial number, and contact Seanav Marine’s 24/7 technical desk for targeted diagnostics.
Get Tokyo Keiki TG8100 Spares & Service Support
Seanav Marine maintains genuine and reconditioned Tokyo Keiki TG-8100/8600 spare parts, replacement PCBs, sensitive elements, and overhaul kits across UAE, India, Oman, Egypt, Singapore, and worldwide ports.
Seanav Marine Technical Operations Desk
Reviewed by Experienced Marine Electronics Engineers & Gyrocompass Specialists • Dubai Maritime City (UAE) & Global Service Stations.
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