GROUNDING INCIDENT PLOTTED AFT WSN-7 AND LOGGED FURUNO POSITIONS STARTING AT 1600Q FINAL Brief: Rev 1.0 QMCM(SW) FAHEY OPNAV N84N3

GROUNDING INCIDENT

PLOTTED AFT WSN-7 AND LOGGED FURUNO POSITIONS

STARTING AT 1600Q

FINAL Brief: Rev 1.0 QMCM(SW) FAHEYOPNAV N84N3

Learning Objectives

• Upon completion of this Lecture the Student will:– Understand the Navigator’s responsibility to

ensure proper navigation equipment setup, operation and maintenance;

– Understand the purpose for following required Navigation procedures;

– Understand how to recognize and prevent faulty electronic positions from being used.

KEY TO DISPLAY

36 FOOT SAFETY DEPTH

CG OUTLINE

WSN PLOT

FURUNO PLOT

RE-PLOT DONE USING VMS 7.7.1. THIS SYSTEM WAS NOT ON BOARD

T- 1600NAVIGATION DETAIL SET AT 1530; SHIP MILLING AROUND, SPEED 5 KNOTS, AT THE TERMINUS OF THE SOUTHERN TSS, WAITING FOR END OF ENG DRILLS. BUOY CB IS JUST TO THE NW OF THE SHIP.

APPROXIMATELY 10 MINUTES EARLIER THE AFT WSN DISPLAYED A ‘223’ ALERT- SYSTEM UNDAMPED (EXCESSIVE TIME)- AT LEAST 84 MINUTES OF UNDAMPED OPERATION . THE SYSTEM THEN COUPLED TO IT’S VELOCITY REFERENCE: VMAN, WHICH IS SET TO 0.0KTS.

Error 223

1600

Q

1545

Q

5 Kts Ord

Aft WSN

T- 1610SHIP MOVES TOWARDS THE TSS, BUT DRILLS CONTINUE. SEA AND ANCHOR WILL BE SET ONE MINUTE AFTER THIS; ONE MINUTE LATER 15 KNOTS WILL BE ORDERED.

BOTH NAVIGATION TEAMS ARE USING NAVSSI (COMDAC) NRS’S FOR POSITIONS; HOWEVER, ONLY THE CIC TEAM LOGS THE POSITIONS. THE BRIDGE LOGS FURUNO GPS POSITIONS.

INVESTIGATORS DETERMINE BOTH NRS’S ARE SHOWING INS2-- AFT WSN-7-- POSITIONS, NOT GVRC1 OR GVRC2 AS REQUIRED.

T- 1618BY 1618 THE ENG DRILLS ARE OVER AND THE SHIP IS HEADED IN. 22 KNOTS HAS BEEN ORDERED AND THE EOOW IS BRINGING UP THE TWO OFF-LINE MAIN ENGINES.

THE BLACK WSN REPLOT IS SLIGHTLY TO THE EAST OF THE FURUNO POSITION AND 3-MINUTE FIXES HAVE BEGUN.

THE BEARING RECORDER, NEWLY ABOARD, WAS DIRECTED TO LOG FURUNO POSITS, ALTHOUGH THE NAV PLOTTER ONLY PLOTS THE WSN-7 POSITION FROM THE COMDAC DISPLAY.

T- 1621THE SHIP IS HEADING UP THE TSS, 25 KNOTS ORDERED AT 1620. THE SEA AND ANCHOR OOD TOOK THE WATCH AT THE SAME TIME.

AT ABOUT 1620, ONE MAIN ENGINE WAS PUT ONLINE, EXIBITED HIGH VIBRATIONS AND WAS AUTOMATICALLY TAKEN OFF-LINE.

IN THREE MINUTES THE SEA AND ANCHOR CONNING OFFICER WILL ASSUME THE WATCH.

BASED UPON THE WSN DATA, THE SHIP IS ON COURSE 294.8T AT 22.8KTS.

Error 223

1600

Q

1630

Q

1545

Q 1615

Q

15 Kts Ord

22 Kts Ord

25 Kts Ord

5 Kts Ord

Aft WSN

T- 1627THE BRIDGE NAV TEAM, SEEING THAT THE SHIP WAS GETTING TO WITHIN 2NM OF ‘RESTRICTED WATERS’, PLOTTED A 1627 INS2 FIX AS THEY SHIFTED TO EVEN- MINUTE (2MIN) FIXES.

CLOSE EXAMINATION SHOWS THAT THE 1627 FURUNO POSITION IS ALREADY AHEAD OF THE 1628 INS2 POSITION- A TOTAL ERROR OF OVER 800 YARDS.

DESPITE THE AVAILABLE NAVAIDS IN THEIR HOME WATERS, THE SHIP IS NOT PLOTTING ANY OTHER FIX SOURCE.

COG- 300.6T, SOG- 23.1KTS

INS2 1628Q

FURUNO 1627Q

T- 1630THE SHIP HAS PASSED BUOY SET 7 AND 8 AND IS SETTING UP FOR THE TURN TO 316T.

THE FURUNO POSITIONS START TO RAPIDLY SEPARATE FROM THE INS2 POSITIONS BOTH NAV TEAMS ARE PLOTTING, AND ACTUALLY PLOTS AHEAD OF THE 1632 INS2 POSITION. THE CURRENT ERROR IS 1200YDS, A 50% INCREASE IN 3 MINUTES.THE INS BEGINS REJECTING THE GPS FIXES.


FURUNOINS2

T- 1634WITH BUOYS 9 AND 10 ASTERN OF THE SHIP, BUT COMDAC SHOWING 9 AND 10 AHEAD OF THE SHIP, CSE 316T IS ORDERED. AN IMPROMPTU EVENT BEGINS ON THE BRIDGE. THIS LASTS SEVERAL MINUTES.

THE SHIP IS 1200 YARDS FROM THEIR 36-FOOT SAFETY DEPTH. THE POSITION ERROR HAS INCREASED TO 1622YDS. SINCE BOTH TEAMS ARE PLOTTING INS2, THEIR FIXES COMPARE WITHIN THE 25YDS REQ’D BY THE CO.

COG- 302.2T, SOG-22.0KTS

T- 1636THE SHIP STEADIES ON CSE 315T. THE 1636 INS POSITION ISN’T VISIBLE ON THIS CHART. A 1MC ANNOUNCEMENT IS MADE AS THE SHIP PASSES BUOYS 11/12.

THIS SLIDE OFFERS THE BEST EXAMPLE OF THE WORSENING POSITION ERROR. THE COMDAC LOG OF THE 1638 GVRC1 POSITION IS CLOSE BY THE 1638 FURUNO AND 1642 INS2 POSITIONS, BUT THE 1638 INS2 POSITION IS 1.28NM ASTERN, WITH INS1 CLOSE BY. GVRC2 IS WITHIN 20YDS OF GVRC1.


T- 1638BY THIS TIME ALL EVENTS ARE COMPLETE. DUE TO THE CLEAR SKIES, THE BRIDGE IS HAVING PROBLEMS SEEING THE BUOYS DUE TO GLARE. THE NAVIGATOR IS LOOKING AT COMDAC TO CONFIRM THE PLOTTED (INS2) POSITIONS. NOTICE HOW AT 1640 THE SHIP WILL BE ABEAM OF BUOYS 13/14, BUT THE COMDAC WILL SHOW THEM ABEAM OF 11/12.

THE FIRST VISUAL LOP, TO CHESAPEAKE LIGHT, IS LOGGED BUT NOT DRAWN ON THE CHART BECAUSE IT DOES NOT COMPARE WITH THE PLOTTED FIX.


FURUNO 1638Q

INS2 1640Q

FURUNO 1640Q

T- 1640SHIP IS JUST ABEAM OF BUOYS 13/14. THE NAVIGATOR HOLDS THE SHIP ON TRACKS AND RECOMMENDS ‘MAINTAIN COURSE AND SPEED’. SET/DRIFT 140T AT 0.4 KTS.

ONLY ONE BUOY SET REMAINS BEFORE THE TURN, BUT COMDAC SHOWS THAT SET 13/14 IS STILL AHEAD OF THE SHIP. TWO VISUAL LOP’S ARE LOGGED BUT NOT DRAWN ON THE CHART.


T- 1642SHIP IS AT THE TOP OF THE TSS, ABOUT TO ENTER THE PRECAUTIONARY AREA. BUOYS 15/16 ARE OFF THE PORT BOW. THE SHIP HAS COME OVER TO 316T.

THE POSITION ERROR HAS INCREASED TO 1.71NM. NAV HOLDS THE SHIP ON TRACK AND RECOMMENDS MANTAINING COURSE AND SPEED. DUE TO THE INS2 ERROR HE BELIEVES THAT HE STILL HAS THIS BUOY SET PLUS ONE MORE SET BEFORE THE TURN.


FURUNO

T- 1644THE SHIP IS IN THE PRECAUTIONARY AREA WITH CAPE HENRY ABOUT 3.3NM TO PORT; 1.73NM OF ERROR EXISTS.

TWO MORE VISUAL LOP’S ARE LOGGED BUT NOT PLOTTED. A TOTAL OF SEVEN HAVE BEEN RECORDED SO FAR. COMBAT HASN’T LOGGED ANY RADAR LOP’S; THE SHIP DOESN’T EXPECT ANY RADAR FIXES UNTIL THE SHIFT TO THE NEXT CHART, 12222.


BUOY NCE

T- 1646ABOUT THIS TIME, PROBABLY AFTER THE NAV REPORT, THE CO ASKS THE NAVIGATOR IF THE BUOY TO PORT IS CH; HE RESPONDS THAT IT’S ACTUALLY RED 16, AND PASSES A 290T BEARING TO CH, BASED UPON THE COMDAC DISPLAY.

THE INS2 POSITION IS 1.98NM BEHIND THE SHIP’S TRUE POSITION. THE 290T BEARING POINTS TO BUOY RED 2C. NO-ONE USES THE SPS-73 RADAR TO LOOK FOR BUOY CH’S RACON. TWO MORE UNPLOTTED LOP’S ARE LOGGED.


BUOY NCE

T- 1648THE SHIP HAS PASSED IT’S NORMAL TURN POINT AND IS ONLY 1650 YARDS (LESS THAN 2MIN AT 25KTS) FROM THE 36-FOOT SOUNDING DIRECTLY AHEAD.

DUE TO THE 1.91NM POSITION ERROR, BOTH NAV TEAMS ARE SETTING UP FOR THE TURN AROUND BUOY CH. IN ONE MINUTE THE NAVIGATOR WILL RECOMMEND HIS SECOND CONSECUTIVE ‘MAINTAIN COURSE AND SPEED’. THE 1646 SET/DRIFT WAS 148T @ 0.2 KTS.


BUOY 2C

290T

T- 1650BASED UPON WSN DATA, AT 16:50:02 THE SHIP BEGAN PITCHING UP AS IT STARTED TO GO AGROUND. IT STOPPED MOVING NORTHWARD 71 SECONDS LATER.

CIC WAS MARKING 500 YARDS TO THE TURN; THE BRIDGE WAS AT 1000 YARDS. THE SHIP THOUGHT IT HAD LOST STEERAGEWAY, OR HAD AN ENGINEERING CASUALTY.

THE POSITION ERROR IS NOW 2.15NM.


BUOY 2C

1.4’ Deviation (Lat)

1.6’ Deviation (Long)

Error 223

1600

Q

1630

Q

1545

Q 1615

Q

15 Kts Ord

22 Kts Ord

25 Kts Ord

5 Kts Ord

Grounding

Aft WSN

T- 1652SHIP’S REPORTED AGROUND POSITION.

THE SCHULER OSCILLATION MADE THE INS2 POSITION MOVE IN A BUTTON HOOK TO THE SOUTH-WEST ACROSS CAPE HENRY, THEN UP TOWARDS BUOY 2C.

AT 1830 THE WSN-7 TECH REPORTED THAT THE WSN’S HADN’T RECEIVED UPDATES FOR THE PAST TWO HOURS. ONCE HE ALIGNED THE WSN’S TO THE GVRC’S, THE POSITION ERROR DIMINISHED.

SHIP’S REPORTED AGROUND POSITION.


AT 1830 THE WSN-7 TECH REPORTED THAT THE WSN’S HADN’T RECEIVED UPDATES FOR THE PAST TWO TWO HOURS. ONCE HE ALIGNED THE WSN’S TO THE GVRC’S THE POSITION ERROR DIMINISHED.

T- 1652

SHIP’S REPORTED AGROUND POSITION.


AT 1830 THE WSN-7 TECH REPORTED THAT THE WSN’S HADN’T RECEIVED UPDATES FOR THE PAST TWO TWO HOURS. ONCE HE ALIGNED THE WSN’S TO THE GVRC’S THE POSITION ERROR DIMINISHED.

T- 1652

1.4’ Deviation (Lat)

1.6’ Deviation (Long)

Error 223

1600

Q

1630

Q

1545

Q 1615

Q

15 Kts Ord

22 Kts Ord

25 Kts Ord

5 Kts Ord

Grounding

~ Time of Aft INS reset

~ Time underway

Aft WSN

‘Hook’

Grounding IncidentGrounding Incident

Swiss Cheese Model of Swiss Cheese Model of Confounding FactorsConfounding Factors

Swiss CheeseERROR

ERROR

Failure to adhere to Failure to adhere to WSN-7 CSOSS proceduresWSN-7 CSOSS procedures

ERROR

ERROR

Perceived pressure toPerceived pressure toarrive on timearrive on time

ERROR

ERROR

Lack of NAVSSI/Lack of NAVSSI/COMDAC knowledgeCOMDAC knowledge

ERROR

ERROR

Failure to use properFailure to use properNavigation proceduresNavigation procedures

ERROR

ERROR

Lack of SituationalLack of SituationalAwarenessAwareness

ERROR

ERROR

How a degraded WSN-7 How a degraded WSN-7 position led to the position led to the grounding.grounding.

WSN-7 was in a Schuler Oscillation that WSN-7 was in a Schuler Oscillation that created a 4300yd position error.created a 4300yd position error.

OVERVIEW

Plotted PositionPlotted Position

Actual PositionActual Position

SUMMARYFIX SOURCES

• Authorized Sources: GPS, Visual, Radar, Composite, in all waters. INS in open ocean, (absolute last resort in restricted waters). NAVSSI Blended (RTS) position …NEVER AUTHORIZED…

• Single Source: GPS only authorized source in all waters, however all sources must be verified with other source at least every third fix.

• Every CO has to specify fix source priority in the NAVBILL for all waters.

SUMMARYAUTHORIZED PROCEDURES

• CSOSS: Verify proper procedures are followed for various operations, Getting U/W, Anchorage, Entering Port, etc.

• NAVDORM: Six rules of DR, Alternate sources, Proper checklist preparation and usage. Proper Logging. Proper detail setup and manning

• BRM: Ensure bridge is utilizing radar, Communication circuits, Backing each other up.

SUMMARY

• STT: Always have STT on station. EVERY transit is a training opportunity.

• Display Setup: Know your choices, and know your equipment- setup, procedures, and standards. NAVBILL must specify settings to ensure safety.

IN CONCLUSION: “Trust But Verify” and Demand Proper Procedural Compliance.

End

Documents

GROUNDING INCIDENT PLOTTED AFT WSN-7 AND LOGGED FURUNO POSITIONS STARTING AT 1600Q FINAL Brief: Rev 1.0 QMCM(SW) FAHEY OPNAV N84N3