PORT ROYAL (CG 73) GROUNDING

Overview Following a 112 Day DSRA, USS Port Royal got underway for Sea Trials. While conducting a RHIB transfer of ATG Air personnel, Port Royal ran aground off the coast of Pearl Harbor.

Initial Data Scaffolding removed from bridge wings until 30 minutes prior to underway OOC equipment: Centerline and Chart table SPA-25G Fathometer (thought to be operational) Underwater log (Pit Sword)

Sequence of Events 0730: Stationed Sea and Anchor Detail 0845: Underway from Pier B7 0856: Loss of Gyro reported (in the turning basin) XSIT: Fathometer read a steady 11-12ft. (Determined to be OOC) XSIT: DFGMC variation was 6 degrees vice charted 10 degrees. 0856: Troubleshooting revealed that only the gyro repeater on the SCC was not indicating ships head. Helmsman shifted to magnetic heading Navigation shifted to relative plot

Sequence of Events 1141: Steering checks conducted (SAT) 1158: Shift to AUX gyro 1201: Shift VMS primary input from GVRC to FWD RLGN 1528: Start DLQ’s and SOVT’s 1805: Flight Ops complete 1923: Set modified Nav detail at 8nm Established a 1nm by 1nm OP BOX 1201: At this point VMS Dead reckoned the ship three times and plotted to ship 1.5 nm from previous position. PLGR was not used 1923: MOD nav detail consisted of Nav evaluator and QMOW – not in accordance with NAV bill.

Sequence of Events NAV Evaluator took over plotting role. Id’ed two tugs in tow and an anchored tanker. Plotted tanker in OP BOX (erroneously) and shifted OP BOX approximately 500 yards further north. 1941: Boat Officer recognizes that magnetic bearing given does not correlate. Attempted unsuccessful communication with Bridge.

Sequence of Events Lookout(U/I) reported waves breaking forward of bow. XO noted seeing silt visible. 2003(approx): Soft aground 2040: Hard aground

RLGN’s LATTITUDE INFO WAS GOOD BUT THERE WAS A RAMP IN THE LONGITUDE INFORMATION THAT LED TO A LARGE POSITION ERROR IN THE AFT RLGN THERE WAS NO EVIDENCE OF A 72-HOUR CALIBRATION. THE 20-HOUR CALIBRATION WAS 10 DAYS PRIOR TO GETTING UNDERWAY. THE LAST RESET PRIOR TO GOING UNDERWAY WAS TAKEN FOUR DAYS EARLIER, SO THE SYSTEM WAS NOT GETTING GPS RESETS. THE VELOCITY REFERENCE WAS SET TO VMAN=0 WHILE UNDERWAY. THE SYSTEM WAS NOT SLEWED OR RESET FROM THE TIME IT LEFT UNTIL AFTER THE INCIDENT. THEY WERE OPERATING IN AN AREA WITH HIGH GRAVITY DEFLECTIONS. THESE FACTORS LED TO A LARGE POSITION ERROR WITH THE GPS INTERFACE NOT ENABLED.

Findings Loss of Gyro DFGMC 6 Degrees vs expected 10 Degrees VMS input shifted to RLGN Silenced/Ignored VMS alarms MOD NAV Detail RLGN only had a 20 hr CAL vice 72 hour CAL RLGN not getting GPS resets Qualified lookouts Unscheduled RHIB transfer CO’s first underway No DR or set and drift on charts Deck log entries inadequate Relied on VMS without question Loss of Gyro: SCC only Alarms: 400 position discrepancy in total Nav detail: minus a second QMOW / CIC not informed Lookouts: Only U/I’s on station. Qualified were FSA’s. Deck logs: incomplete course/speed/rudder info. Evolutions were not recorded.

Conclusions Reconstructed track shows approximately a 3600-3700 yard offset to the East Labeled fixes as satellite fixes when VMS aligned to RLGN. Ship did not remove all way when position in doubt Total damage cost = $20,000,000

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