System Architecture: Sperry Marine NAVIGAT X MK 2 Compact Gyro
The Sperry Marine NAVIGAT X MK 2 (Type 4911 / Type 4916) is a cost-effective, compact commercial gyrocompass engineered specifically for vessels where wheelhouse space is constrained, including offshore supply vessels, tugs, mega yachts, coastal tankers, and fishing vessels. Built upon the proven gyrosphere design of the NAVIGAT family, the MK 2 integrates the master compass, control unit, and distribution circuitry into a single monoblock housing.
Features include a high-contrast integrated digital heading display, automatic latitude error correction from GPS, manual speed input, and rapid North-seeking settle sequence, maintaining full IMO A.424(XI) type approval.
Technical Specifications: NAVIGAT X MK 2
| Parameter | Specification Details |
|---|---|
| Model Type | Type 4911 / 4916 Compact Master Gyrocompass |
| Gyrosphere Element | Type 074882 / 074829 twin-rotor hermetically sealed floating element |
| Settle Time | < 3 hours (typical settling time at moderate latitudes) |
| Static Heading Accuracy | ≤ 0.1° secant latitude |
| Dynamic Heading Accuracy | ≤ 0.4° secant latitude under standard sea conditions |
| Follow-Up Speed | 100°/second follow-up tracking rate |
| Interfaces & Outputs | 4x RS-422 NMEA 0183 ($HEHDT, $HEROT), 1x 6-Step/Degree (24V DC), Status Alarm Relays |
| Operating Voltage | 115 / 230 V AC (50/60 Hz) ±10% with emergency 24 V DC input |
| Power Consumption | Approx. 80 W running (120 W during rotor spin-up) |
Core Components & Replacement Spare Parts
| Component | Part Number | Technical Details |
|---|---|---|
| Gyrosphere Element | 074882-0000-000 / 074829 | Twin-rotor floating sphere calibrated for compact container |
| Container Assembly | 074883-0000-000 | Sealed container bowl with centering electrodes and contact pins |
| Supporting Liquid | 074830-0000-000 | Electrolytic supporting fluid bottle (approx. 1000ml) |
| Control & Display Board | 074884-0000-000 | Front panel display PCB with keypad and digital heading readout |
| Inverter & Follow-Up PCB | 074885-0000-000 | Integrated inverter drive and azimuth follow-up servo motor amplifier |
| Power Supply Board | 074886-0000-000 | AC/DC power management and 24V DC battery switchover circuitry |
| Container Cooling Fan | 074887-FAN | Brushless DC cooling fan ensuring optimal thermal equilibrium |
| Overhaul Gasket Set | 074888-GSK | High-temperature silicone gaskets, O-rings, and sealing washers |
Seanav Service Procedures for NAVIGAT X MK 2
Seanav Marine maintains comprehensive inventory of NAVIGAT X MK 2 replacement gyrospheres, supporting liquids, and PCB boards at key global ports:
- Routine Annual Inspection: Testing flotation current, verifying fluid level through the sight glass, measuring electrolyte specific gravity, and checking cooling fan airflow.
- 3-Year Container Overhaul: Draining supporting liquid, cleaning container electrode pins, replacing O-rings, installing re-certified gyrosphere, and refilling with fresh fluid.
- Autopilot & Repeater Calibration: Confirming serial NMEA sentence integrity and synchro/step transmission synchronization across all bridge repeaters.
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