129Departmental investigation

into the incident involving

the Singapore flag cattle carrier

CARABAO 1

in which the vessel dragged

anchor, contacting the jetty

and four moored vessels at the

Western Australian port of Broome

on 14 January 1998

Report No 129

Navigation Act 1912

Navigation (Marine Casualty) Regulations

investigation into the incident involving

the Singapore flag cattle carrier

CARABAO 1

in which the vessel dragged

anchor, contacting the jetty

and four moored vessels at the

Western Australian port of Broome

on 14 January 1998

Issued by the

Marine Incident Investigation Unit

May 1998

ISBN 0 642 20006 8

Investigations into marine casualties occurring within the Commonwealth'sjurisdiction are conducted under the provisions of the Navigation (MarineCasualty) Regulations, made pursuant to subsections 425 (1) (ea) and 425 (1AAA)of the Navigation Act 1912. The Regulations provide discretionary powers to theInspector to investigate incidents as defined by the Regulations. Where aninvestigation is undertaken the Inspector must submit a report to the Secretary ofthe Department.

It is Departmental policy to publish such reports in full as an educational tool toincrease awareness of the causes of marine incidents so as to improve safety at seaand enhance the protection of the marine enviroment.

To increase the value of the safety material presented in this report readers areencouraged to copy or reprint the material, in part or in whole, for furtherdistribution, but should acknowledge the source. Additional copies of the reportcan be obtained from:

Inspector of Marine AccidentsMarine Incident Investigation UnitGPO Box 9879CANBERRA ACT 2601

Phone: 02 6274 7324Fax: 02 6274 6699Email: miiu@miiu.gov.au

MIIU on the INTERNETInformation relating to this report and other marine investigation reports can befound in the Marine Incident Investigation Unit's Internet homepage at our URL:

http://www.miiu.gov.au

Contents

Summary ............................................................................... 1

Sources of Information .......................................................... 2

Acknowledgement...............................................................................2

General .................................................................................. 3

Port of Broome ...................................................................................3

Carabao 1, 23 December 1997 to 14 January 1998.............................4

Carabao 1, 14 January 1998 ...............................................................4

Comment and Analysis ......................................................... 7

Evidence ............................................................................................7

The Weather .......................................................................................7

Storms in the Broome area .................................................................9

Ship watchkeeping ............................................................................ 10

The incident ...................................................................................... 10

The anchorage ................................................................................. 13

Conclusions ........................................................................ 17

Submissions ........................................................................ 19

Details of Carabao 1 ............................................................ 21

Photographs and chartsPhotograph of Carabao 1 ........................................................................................ next pagePortion of chart Aus 50 showing location of anchor positions ............................................ 11Broome jetty and anchorage ............................................................................................... 12

Summary

On 8 January 1998, the Singaporeregistered livestock carrier Carabao 1anchored with 3 shackles of cable about240 m off the outer berth of the jetty, inthe port of Broome in the north-west ofWestern Australia. The holding groundwas considered to be good and the vessellay securely at anchor to the tides andwesterly winds that predominated overthe next six days.

On 14 January, westerly winds of between10 and 15 knots were experienced,dropping in the early evening to a gentle5 knot westerly breeze. At about 2225,about one and half-hours before highwater and with the ship lying to the tidalstream and heading north-east, a suddensquall was experienced at Broomegenerating storm force easterly winds.Within seconds Carabao 1 started to draganchor, directly toward the outer berth.

The Master, who was on watch, informedthe engine room that he required theengine immediately, and called out thecrew. The Chief Mate and Boatswainwent forward to stand by the windlass.

At about 2228, the vessel’s starboardbow, just aft of the anchor, came intocontact with the eastern corner of thejetty. The vessel, drifting rapidly in awesterly direction, was then driventhrough the moorings of local fishingvessels. Four vessels were damaged, oneof which broke from its moorings andwas driven beneath the jetty by the windand tide.

Between 2230 and 2235, the anchor heldonce more and Carabao 1 came to a stopclose to the shore. Soundings at theship’s stern showed that there was aboutone metre of water under the keel.

By 2245 the wind had dropped below 20knots and the ship was able to recover itsanchor at 2318 and move clear of thesmall craft moorings. By this time thewind had dropped completely away andCarabao 1 anchored once more, 440 moff the outer berth.

Nobody was injured as a result of thisincident. In addition to the four smallervessels damaged, Broome jetty sufferedsome damage, Carabao 1 sustained anisolated indentation to its hull platingforward and some superficial paintdamage.

Sources ofInformation

The Master and crew of Carabao 1

The Pilot, Port of Broome

The General Manager, Port of Broome

The Bureau of Meteorology, Broomeobservation station

Western Australian Police Service,Broome

The Broome Volunteer Sea Search andRescue Group

Members of the public fishing from thejetty at the time of the incident

The Bureau of Meteorology, Perth

The Australian Tidal facility, FlindersUniversity

AcknowledgementThe Inspector gratefully acknowledgesthe assistance of the Officer in Charge,Broome Meteorological ObservationStation.

Portion of navigation chart Aus 50reproduced by permission of theHydrographic Office, RAN.

Narrative

GeneralCarabao 1 is a single hold livestockcarrier of 1941.3 tonnes deadweight, withan overall length of 69.73 m, a beam of13.21 m and a summer load draught of5.312 m. Built in Haugesund, Norway, in1974 as a general cargo/heavy lift shipprimarily for the Baltic trade, the vessel isstrengthened for ice and, as such, the hullis ideal for a trade where the vessel sits onthe bottom in tidal rivers. The vessel isequipped with a magnetic compass, radar,GPS and echo sounder.

Main propulsion is by means of a 1394 kWAlpha diesel engine driving a single,variable pitch propeller in a fixed Kortnozzle, providing a service speed of 12knots. The vessel is also equipped with abow thruster. At the time of the incident,neither the bridge control of the variablepitch propeller nor the bow thruster hadbeen functional for some considerabletime.

The vessel was purchased by the presentowner, Labroy Marine (Pte) Ltd ofSingapore, in 1994 and was the second ofthree vessels purchased and converted forcarrying cattle in the developing tradebetween northern Australian ports and theArchipelagic Islands to the north.

Carabao 1 is manned by a Filipino masterand crew comprising two deck officers,three engineer officers, an electricalofficer and eight ratings. An Australianstockman is also carried.

The Master and two deck officersmaintain traditional four on eight offwatches, with the Master keeping the 8 to

12 watch. The engine room is notequipped for unmanned machinery spaceoperation and the three engineer officersmaintain a similar watch system with theChief Engineer keeping the 8 to 12 watch.At anchor, the engine room rating keptthe evening watch from 2000, with theChief Engineer supervising him andpaying regular visits to the engine room.

Port of BroomeThe Port of Broome is situated at thenorthern end of Roebuck Bay in thenorth-west of Western Australia. Shipsberth at the end of an “L” shaped jetty700 m in length. The port is capable ofhandling vessels of 187 m in length,which can berth on the outer side of thejetty, while smaller vessels can berth onthe inner side of the jetty.

The area of water immediately off theberth is a prohibited anchorage, thoughvessels do anchor in this area under thePilot’s direction. The bottom is sand andis good holding ground. Large cruiseships and tankers have anchored in thisarea in strong winds and maintained theiranchor positions without difficulty.Between the jetty and the north and eastof the shoreline a number of mooringshave been laid for local fishing andpearling vessels.

The port is visited about once a week bytrading ships with gross tonnages inexcess of 500. At night the port office isnot manned and there is no scheduledradio station within VHF range, althoughthe volunteer Coastwatch station ismanned if required and in emergencies.

Broome has a large rise and fall in tidalheight, with a maximum range of 10 m atspring tides.

Carabao 1, 23 December 1997to 14 January 1998Carabao 1 sailed from General Santos, aport on the Philippines island ofMindanao, on 23 December, with initialorders to return to Darwin. Bad weatherand heavy seas forced the vessel to shelterin the Indonesian Archipelago and whenthe weather abated, the vessel wasdirected to Broome, Western Australia, toload livestock.

At 1006 on 7 January 1998, Carabao 1anchored off the fairway to BroomeHarbour. The weather was fine but thewind was fresh to strong, force 5 to 6 onthe Beaufort scale. The vessel had beenat sea longer than anticipated andrequired stores and the opportunity toundertake some minor engine repairs.The distance from the port and the seaconditions at the exposed anchoragemeant that stores could not be taken to theship and the engine could not be shutdown, even for a short period in theprevailing conditions.

The Master requested, through thecharterers, that the vessel be allowed toanchor in the shelter of Broome Harbour.No other trading ship was due until theend of January and it was agreed thatCarabao 1 should be allowed to anchor inthe harbour in what is normally aprohibited anchorage area.

On the afternoon of 8 January the Pilotboarded Carabao 1 and took the vessel toan anchorage in the port. At 1816 thevessel was anchored using the port anchorwith three shackles of cable in 11 m ofwater, about 240 m east of the outer endof the jetty. The Pilot made a particularpoint of ensuring that the cable wasproperly stretched.

The Master issued orders that the ship’sposition was to be carefully monitored

and that if necessary, the engine was to bestarted. The officers were also tomaintain a careful watch on thebarometer.

On 8 January a further half shackle ofcable, about 14 m, was paid out. Over thenext few days, stores were taken onboard, the crew prepared the ship forcarriage of livestock and minor enginerepairs were completed.

Carabao 1, 14 January 1998The morning and evening of the14 January proceeded routinely withanchor watches being maintained. Thewind was from the west averaging aboutten knots throughout the day, decreasingin the evening to a light breeze. Lowwater was at 1805 at 0.7 m above datumand high water at 2352 with a predictedheight of 8.5 m. Sunset was at 1833,nautical twilight was at 1925 and therewas a bright full moon which rose at 1938that night.

At 2000, the anchor position was checkedand the barometric pressure was recordedin the log as 1010 hPa. The wind wasnoted as variable force 4. The Mastertook over the anchor watch from theMate. One of the deck ratings was alsoon watch covering the period 1800 to2400. The oiler was on watch in theengine room, with the Chief Engineer oncall in his cabin. The Chief Engineervisited the engine room every 20 to 30minutes.

At 2045 the wind dropped to a lightbreeze and Carabao 1 lay quietly to theflood tide in calm conditions. The ship’sradar was operating mainly on the 1.5mile range scale and the variable rangemarker was set on the outer end of thejetty.

At about 2225 the ship was hit withoutwarning by a sudden, storm force easterlysquall. The ship swung head to wind andthe Master realised almost immediatelythat the ship was dragging its anchor. Heordered the seaman on watch to call thecrew and rang the engine room to havethe engine started. This phone call wasimmediately acknowledged by the engineroom rating.

The Mate was on his way to the bridgewhen he met the seaman descending theshort flight of stairs from the bridge andhe returned to his cabin then went to theforecastle deck, where the Boatswainjoined him. The Chief Engineer andSecond Engineer went to the engine roomimmediately, where the Third Engineerand the Electrician joined them. TheSecond Mate, who had been asleep,dressed hurriedly and went to the bridge.Meanwhile, the ship drifted rapidly out ofcontrol, virtually port beam to the windand with the starboard side towards thejetty.

After ordering the engine prepared forimmediate use, the Master’s initialreaction was to pay out more cable on theport anchor but, before the Mate andBoatswain could put the windlass intogear, the ship contacted the eastern end ofthe jetty, just aft of the starboard anchor.The time logged for striking the jetty was2228. Striking the jetty did not arrest theship’s drift and Carabao 1 was drivenfurther west, through the moorings offishing and pearling boats north of thejetty.

At 2230 the ship’s engine was ready, butbefore manoeuvring, the Master sent theSecond Mate and Rating aft to check thatthe ship was still afloat. At about thistime the ship’s anchor apparently dug inor fouled a mooring and the ship’s

progress was arrested. The wind speed atthis time had decreased but remainedstrong.

The rating tied a weight to a heaving lineto take soundings around the stern andmeasured the wet line in terms of the fullspan of his arms. By this method it wasestablished that the vessel’s stern wasafloat. The Master then ordered deadslow ahead on the engine and started totry and recover the anchor. The enginewas intermittently run at ahead pitch,dead slow and slow from 2235 until justafter 2306, while the anchor was beingrecovered and the vessel was thenmanoeuvred back to the anchorage. Thepitch was put dead slow astern at about2313 for one minute, before being put tozero at about 2314. It remained at zeropitch until 2333 when finished withengine was rung.

That night, a number of people werefishing from the jetty. Four people werefishing from the outer end and, when thesquall hit, they quickly gathered up theirbelongings with the aim of walking thelength of the jetty to their car. As they didso, they looked up and saw the starboardside of the ship closing the end of thejetty with great rapidity. They could seelow level lights in the cattle pens, someaccommodation lights, the forwardanchor light and an all round white lightat the masthead. They saw the ship’sstarboard side strike the jetty and,although the accounts differ in detail, twoof the witnesses thought that it was thebow area that had contacted the jettyinitially.

The wind was so strong that they wereunable to walk along the exposed jettyand they sought shelter on the lee side ofthe wharf shed. One of the party went toa phone booth at the end of the shed and

telephoned the police informing them thata ship had broken loose and had hit, andpossibly sunk, vessels moored close to thejetty. The call was logged at the PoliceStation in Broome at 2235.

A police car with two officers, one ofwhom was a member of the BroomeVolunteer Sea Search and Rescue Group,was just pulling into the Police Stationand the officers were diverted to the portsome 6 km away, where they arrived atabout 2240. Initially they went to a carpark at the western end of the jetty fromwhere they could clearly see Carabao 1about 200 m to 300 m away and so closeto the shore that it seemed to be aground.A local fishing vessel was also seen tohave broken from its moorings and tohave drifted under the jetty.

The Police alerted the General Managerof the Port, the Pilot and a member of theVolunteer Coastguard to the situation inthe port and asked the latter to open upthe volunteer radio station.

The General Manager arrived at the jettyat about 2250 and saw the vessel closeinshore, apparently stopped in the water.The wind, although fresh, had reduced inintensity by this time.

The Pilot arrived a few minutes later andsaw the ship with its navigation lightsexhibited, apparently underway. Hejudged the ship was in dangerouslyshallow water and drove along the jetty tothe Port office from where he called theship on VHF Channel 16 at a time loggedby the ship as 2256. He asked if the shiphad its echo sounder switched on. Theship confirmed that the echo sounder wasrunning and showed six meters under thekeel. The Pilot advised the Master toanchor and await further orders, and theMaster anchored 2.53 cables off the endof the jetty, using the port anchor and 4shackles of cable. The Pilot spoke to theMaster after the vessel was anchored andadvised him to put out sufficient cable toprevent dragging. At about this time, thewind had died away and there was little orno breeze until later the followingmorning when light westerly airs wererecorded.

The efforts of the Port personnel werethen concentrated on extricating thefishing vessel from under the jetty, withthe help of the Pilot boat and anothercraft. This was achieved at 0130 on15 January, and three other boats believedto have been hit by Carabao 1 wereidentified.

Comment andAnalysis

EvidenceCarabao 1 was not equipped with anyautomatic recording device. Times ofevents were kept on board in bell ormovement books. The Bridge Bell bookwas used to record times of significantevents such as anchoring or pilot arrivaland departure times. It was not used torecord the time of engine (propeller pitch)movements. Times of engine movementorders were kept in an “Engine RoomMovement Book”.

Bridge records of this incident wereextremely neat and it is hard to imaginethat the writing would be so uniform ifthe entries were contemporaneous withevents, given the urgency and stressprevailing on the bridge. The engineroom movement book, however, appearsto be a running record of the actualengine movements.

According to the bridge bell book, afterCarabao 1 had ceased dragging anchor,the vessel commenced weighing the portanchor at 2236, and at 2318, the anchorwas logged as being ‘up’. The next entryin the bridge bell book states that at 2328,the port anchor was dropped with 4shackles in the water, 2.53 cables off thejetty in accordance with advice receivedfrom the Pilot.

The engine movement book indicates thatthe last engine movement was dead slowastern at 2313:15, and that the engine wasstopped at 2314:15. There were nofurther engine movements that night, andthis would suggest that the vessel

anchored off the jetty at 2314, rather thanat 2328.

There are inconsistencies between bridgeand engine room records of movementson the night of 14 January, and it is notpossible to reconcile timings kept by theengine room of engine movements, withtimes of events kept by the bridgebetween 2225 and 2335.

During the investigation into thisincident, the bridge and engine roomclocks were compared and it was foundthat there was a difference of about aminute between the clocks, with theengine room clock one minute slow onthe bridge clock.

The Police Station logged the time of theinitial call to their station by therecreational fisherman who witnessed theincident as 2235. All other times givenby witnesses are approximate only.

The Bureau of Meteorology’s observingstation at Broome Airport providedanemometer charts and a video of theweather radar picture from 2030 to about2300. These give an accurate picture ofthe weather, although the local marinecommunity report that conditions betweenthe airport and the jetty, 6 km away, canvary significantly, particularly in relationto wind speed.

The Australian Tidal Facility has a tidalgauge at Broome Jetty. This facilityrecords tidal height, barometric pressure,wind speed and direction. These recordswere provided to the Inspector.

The WeatherJanuary weather in Broome ischaracterised by hot days, very warmnights and high humidity. It is the periodleading to the “wet” season in that part of

Australia, characterised by frequentthunderstorm activity.

The domestic weather forecast issued bythe Bureau of Meteorology for Broomeon the evening of 14 January and the dayof 15 January, was for west to north-westwinds with risk of afternoon or eveningthunderstorms, a minimum temperature of19°C and a maximum temperature of34°C.

Carabao 1 recorded the wind throughoutthe day of 14 January as westerly force 4(11-16 knots) with a maximum dailytemperature of 36°C, dropping to 30°C by2000.

The weather radar at Broome records theradar display every ten minutes. At 1920on 14 January (141120z), the leadingedge of an isolated accumulation ofcloud, apparently a storm-cell, could beseen on the radar 250 km east of Broometracking in a westerly direction. By 2010the leading edge of the cloud was at 200km tracking directly for Broome. Theradar indicated that the moisture levelwithin the cloud would cause between 10and 20 mm/hr of rain, however, the radaris unable to calculate the speed of windsassociated with such systems.

Analysis of the radar shows that thesystem moved at an average speed of 80km/hr. At 2110 (141310z) the cloud bankwas 125 miles from the radar and at 2150,50 km due east of the town. At 2230, theradar shows the town, port area and Bayenveloped in cloud. By 2400 on14 January, the cloud was about 100 kmwest of the coast and dissipating.

The anemometer trace shows that from0900 on 14 July, until about 1800, thewind was westerly averaging about 10knots. Over the next few hours the windspeed dropped and at 2200 was two tothree knots from the west-south-west.

Between 2224 and 2228 the wind speedincreased from 3 knots to 40 knots, andthe wind direction shifted from west-south-west to east-north-east. At 2232 amaximum gust of 42 knots was recordedat the weather station. By 2236 the windhad decreased to 30 knots. For the nextten minutes the wind strength variedbetween 20 and 31 knots, before dyingaway to 2-5 knots from a general westerlydirection.*

The wind gust, as reported by a Policepatrol, hit the town at 2225. Thewitnesses on the jetty were not sure of thetime the storm hit the port area. They diddescribe having to hold onto a light poleto prevent being blown over and it wassome minutes before they were able totelephone the Police to warn of thedrifting ship.

Records received from the AustralianTidal Facility of Flinders Universityindicate that at 2200 the wind was fromthe west-south-west at about 7 knots withoccasional gusts to about ten to 12 knots.The barometric pressure was 1009.6 andrising steadily.

Between 2200 and 2300 the maximumwind speed recorded was 54 knots (28 m/s)from the east with a maximum barometricpressure of 1011.1 hPa. There is norecord of time of this maximum gust, but

* The Meteorological station has two anemometers.The second, high speed, anemometer is about oneminute fast of the standard instrument and showeddead calm from about 1830 and a maximum windspeed of 46 knots at about 2230.

it is reasonable to assume that this was thesquall reported at about 2225. The windspeed, about 15 knots higher than thatrecorded at the Meteorological Station atthe air port, is consistent with a windspeed of Beaufort Force 11 (56-63 knots)estimated by the Master.

The Australian Tidal Facility data alsoshows that at 2300 the wind was east ofnorth and the speed had fallen to 15 knotsand continued to decrease into themorning of 15 January with the windreverting to a westerly direction by 0200.

At 0412 on 16 January, a similar suddensquall hit Broome Harbour with winds of40 knots from the south-east causingCarabao 1 to start to drag anchor onceagain. The build up to the squall wasmore gradual, however winds of over 30knots lasted for about 30 minutes. Onthis occasion, the engine was used toreduce the weight on the cable and, afterthe squall passed, the anchor was weighedand the ship was repositioned.

Storms in the Broome areaThe Pilot, the Police and othersinterviewed stated that isolatedthunderstorms are a frequent occurrencein January, however, the stormexperienced by Carabao 1 on 14 Januarywas unusual in its intensity and ferocity.

The Coastal Waters Weather Forecast forthe 14 January predicted west to north-west winds of 8 to 18 knots. The“Provincial Towns” forecast for Broomepredicted the risk of an afternoon/eveningthunderstorm, and west to north-westerlywinds. This forecast is not unusual for thetime of year. The observing weather

station at Broome is unmanned fromabout 2000 and the approaching cloudfrom the east would not have beennoticed on the radar.

The Australia Pilot, Volume V1 , warns:

“The approaching hot season of the NWMonsoon is preceded by sharp, short-lived squalls of increasing frequency andintensity. Squalls can produce winds ofgale force and are often accompanied bythunderstorms. As they pass over theremay be a sharp drop in temperature and arise in pressure, whilst a sudden stronggust of wind may occur.”

However, Australia Pilot, Volume V doesnot give any further detail andinformation from the Broome climatictable would suggest that easterly winds inthe afternoon occur only on 6 per cent ofoccasions and they are light at about 3knots.

The Bureau of Meteorology providedstatistics on the frequency ofthunderstorms moving from east to westduring the three month period Decemberto February over ten years from 1987 to1997. Over this ten year period anestimated 143 such storms moved acrossBroome. Thirty seven of these stormsgenerated winds in excess of 30 knots and10 storms, or 7 per cent of the totalnumber, generated winds in excess of 40knots.

The Master received the coastal weatherforecast, but the ship did not listen to landbased weather forecasts. The formationof storms and accompanying squalls maybe common to north and north-westAustralia at this season, however there

1 Australia Pilot, Volume V, North and North-Westand West Coasts of Australia from the West Entranceof Endeavour Strait to Cape Leeuwin, SeventhEdition, 1992

was little to warn the Master of thefrequency or potential severity of suchsqualls. No information of the possibilityof such storms was provided to him bythe Port Authority.

Ship watchkeepingFollowing the incident on 14 January,allegations were made by witnessesashore that Carabao 1 was notmaintaining a proper anchor watch.

The evidence is that a qualified navigatorwas on the bridge throughout the ship’stime at anchor. The engine room was notleft unattended, though at night an engineroom rating, rather than a qualifiedengineer, maintained a watch with anengineer officer on call and makingperiodic visits to the engine room.

The Master’s “Bridge Order Book”contained the entry for each day at theanchorage instructing the officer of thewatch that if any dragging of the anchorwas detected, the duty engineer was to becalled to start the engine and the Masterand Boatswain were also to be called.

There was some ambiguity in theunderstanding of engine readiness. TheMaster and Chief Engineer stated that theengine was on immediate notice forstarting. The turning gear was notengaged and the lubricating oil andancillary equipment were kept running.The starting air in the air bottles wasmaintained between 24 bar and 30 bar.However, it seems that the term“immediate” was accepted as being about10 minutes under normal conditions,although with the small engine size itshould have been a case of just the initialmovement of the fuel lever to start it.However, because there was no engineer

officer in the engine room when thesquall struck, the engine was not starteduntil the Chief Engineer arrived at theengine control position. The evidence isthat the engine was ready within fiveminutes, probably about three minutes,from the time the engine room was firstalerted.

There is no substantive evidence tosuggest that the proper watches were notbeing maintained on board Carabao 1.Although it is possible that the enginecould have been available three minutesearlier at about 2227, given the force ofwind experienced within seconds ofarrival of the squall and the proximity ofthe ship to the wharf, contact with thewharf would not have been prevented.Whether the further drift of the vesselafter 2228 could have been prevented isopen to conjecture.

The incidentThere is no doubt that the squall struckwithout any warning shortly after 2225.There was nothing that the ship couldhave done to predict the arrival of thesquall or the wind speed, which reached54 knots within a few minutes.

By the time it was realised that the anchorwas not holding, the vessel may havebeen less than 70 m or a ship’s length,from the jetty. There was very little timefor the Master and crew to react and thevessel struck the jetty before the enginewas available.

As well as informing the engine room thathe required to use the engine immediately,the Master’s other reaction was to pay outmore anchor cable, in the hope that thiswould allow the anchor to dig in and holdthe ship.

Portion of chart Aus 50 showing anchor positions of Carabao 1

It is not clear how long it took for theMate and Boatswain to reach theforecastle head. The Mate’s evidence wasthat the vessel was virtually alongside thejetty when he arrived on the forecastle,and witnesses ashore reported that whenthey first realised the ship was moving,they did not see anyone on the forecastle.

When the Mate and Boatswain reachedthe forecastle, instead of paying out morecable by releasing the brake, the Mateintended putting the windlass into gear to“walk back” cable from the ship. If theyhad succeeded in walking back cable withthe windlass in gear, it is doubtful if thewindlass could have paid out sufficientcable to halt the vessel’s drift. TheMaster stated that it was the practiceaboard Carabao 1 under adverseconditions, to pay out cable with thewindlass in gear, because this was saferthan controlling cable with the brake.

In any event before any more cable couldbe paid out, the vessel hit the jetty. In theopinion of the Inspector, it is probablethat the vessel was too close to the jetty topay out enough additional cable and haltthe ship’s drift, either by walking backcable with the windlass in gear, or byreleasing the brake. Given the speed withwhich the ship was drifting, there waslittle that could have been done to avertthe immediate consequences of theanchor dragging as, by the time theengine was ready, the ship had struck thejetty and drifted further west. The Masterconsidered letting go the starboard anchorbut, in his opinion, the vessel was tooclose to the jetty to permit this anchor tobe used.

The engine was ready shortly after theship made contact with the jetty but theMaster delayed using the engine until hewas sure the vessel was afloat and the

propeller was clear. During this timeCarabao 1 came into contact with foursmall vessels moored between the jettyand the shore. Events occurred so rapidly,it is doubtful if use of the engine as soonas it was ready would have establishedcontrol of the vessel and stopped itdrifting, in time to prevent contact withthe small craft.

The ship was extremely lucky that afterdragging anchor so swiftly in such aconfined area, the anchor held again andprevented the vessel from grounding.This gave the Master the opportunity toestablish that it was safe to use the engineand manoeuvre, away from the lee shore,back to the anchorage.

The inconsistency in times between thebridge and engine records and the lack ofany other supporting evidence makes anaccurate reconstruction of events difficult.The propeller pitch movements after 2301(two at dead slow ahead for just under atotal of six minutes, and the dead slowastern pitch logged at 2313:15) wouldsuggest that the ship was in its newanchorage position at about 2313, ratherthan 2328 as recorded by the bridge. Thebridge records, as previously stated,cannot be relied upon. The Inspector seesnothing sinister in this, and it probablyreflects the stress of the moment.

It seems from eyewitness accounts, thatbetween 2228 and 2234, Carabao 1 haddragged anchor over a distance of 600 mor more before the anchor held andarrested the drift.

The anchorageThe area off the berth is designated aprohibited anchorage and is not used ifother vessels are expected to berth at thejetty. As no other vessels were expected

during Carabao 1’s stay, the vessel wasanchored off the wharf. The seabed issand and is considered to provide goodholding ground. Tankers over 180 m inlength and cruise liners with significantwindage have anchored safely in strongwinds in the anchorage to the east ofBroome Jetty.

Carabao 1 is equipped with port andstarboard anchors, each of 1.59 tonnes,attached to 34 mm diameter chain. Thestarboard anchor is attached to 8 shacklesof cable (220 m) and the port anchor to 7shackles (192 m).

The vessel anchored in a charted depth ofabout 10 m, using about 100 m of chainmeasured from the anchor to the hawsepipe, allowing a vertical distance of about3 m between the hawse pipe and thewater. The predicted range of tide ofabout 8.0 m on 14 January meant thatCarabao 1 would have been in amaximum depth of 18 m of water and aminimum of 10 m. Based on the formulafor the minimum cable required, 25 D(where D is the depth of water in metres),Carabao 1 required 106 m. The scope2

of chain deployed varied between 5 and7.7. The scope of Carabo 1’s cable wasvery close to that recommended in theory.

Carabao 1 is about 70 m in length. Whenthe ship anchored on 8 January 1998, theanchor was dropped approximately 240 meast of the end of the jetty, and 3 shacklesof cable were paid out in the water. TheMaster subsequently paid out anestimated further half shackle making atotal length of chain of 3½ shackles or 96 mof chain in the water. With the chainstretched out the radius of the circlecentred on the anchor and described bythe ship’s stern was about 170 m, which,

given the right circumstances, meant thatthe stern could swing as close as 70 mfrom the jetty.

A number of witnesses stated thatCarabao 1 was lying in a north-easterlydirection. When the squall struck, theanchor cable would have become bar tightand would, in all probability, have liftedthe anchor shank causing the anchor tobreak out of its ground. It seems that thevessel then sheered in a clockwisedirection till the wind was on the portbeam, and dragged anchor till it struck thejetty and four small craft before comingto a stop.

The dragging of Carabao 1’s anchor isthe fourth similar incident investigated bythe Unit since November 1995.3

The investigations into these incidentshighlight the International Association ofClassification Societies design standardsfor anchors. The anchoring equipment isintended for temporary mooring within aharbour or sheltered area when the vesselis awaiting a berth or the tide.

A1.1.2 The equipment is therefore notdesigned to hold a ship off afully exposed coast in roughweather or to stop a ship which ismoving or drifting. In thiscondition loads on the anchoringequipment increase to such adegree that its components maybe damaged or lost owing to thehigh energy forces generated,particularly in larger ships.

Anchoring equipment is designed to holda ship in good holding ground. The sizeof the equipment is based on the ship’sdisplacement at summer load water line,3 See Incident reports No.86, No. 91 and No. 1032 The length of cable laid out measured from the

hawse pipe to the anchor divided by the verticaldistance between the hawse pipe and the sea bed.

the ship’s breadth and the area of hullabove the summer load water lineexposed to wind.

A1.1.4 The Equipment Number formulafor anchoring equipment hereunder is based on assumedcurrent speed of 2.5 m/sec, windspeed of 25 m/sec4 and a scope ofcable between 6 and 10, the scopebeing the ratio between the lengthof chain paid out and water depth.

Anchors provide maximum holdingpower when the cable is pullinghorizontally at the anchor shank. Theefficiency of the anchor is reducedsignificantly as the angle between thehorizontal and the cable at the anchorshank increases. A rule of thumb is that apull 5° above the axis of the anchor

reduces the holding power by 25 per centand a pull of 15° above the axis of theanchor reduces the holding power by 50per cent5 .

In the particular circumstances theproximity of Carabao 1 to the jetty wasan important factor. The Pilot consideredthe anchorage to be safe, and the Masterdid not question the Pilot’s judgement.Although anchored in proven holdingground, in the event of the anchordragging in an easterly wind there waslittle time to react.

However, the prevailing and forecastwind was from the west and if the shiphad dragged to the prevailing wind therewas 500 m clear water between theanchor and shoal water to the east, givinga reasonable margin of safety.

4 4.86 knots current, 49 knots wind speed5 Danton, G., The Theory and Practice of Seamanship,10th Edition Revised. (1987), Routledge, London

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Conclusions

These conclusions identify the differentfactors contributing to the incident andshould not be read as apportioning blameor liability to any particular organisationor individual.

The following factors are considered tohave contributed to Carabao 1 dragginganchor:

1. The proximity of the ship’s anchorposition to the jetty in the event thatCarabao 1 was driven toward thewest.

2. There was no information availableto the Master to warn him of thepossibility of squalls developing andcausing strong easterly winds.

3. The delay, however minimal, ofstarting the ship’s engine

It is also considered that:

4. The likelihood of occurrence ofsuch squalls should have beenknown to the local harbour authorityand the pilot.

5. Even if, with the engine available,contact with the jetty could not beprevented, there was the possibilitythat dragging of the anchor furtherwest through moored small craft,could have been avoided.

Submissions

Under sub-regulation 16(3) of theNavigation (Marine Casualty)Regulations, if a report, or part of areport, relates to a person’s affairs to amaterial extent, the Inspector must, if it isreasonable to do so, give that person acopy of the report or the relevant part ofthe report. Sub-regulation 16(4) providesthat such a person may provide writtencomments or information relating to thereport.

The final draft of the report, or relevantparts thereof, was sent to the following:

The Pilot

The Master

The Chief Engineer

An acknowledgement was receivedfrom:

The Pilot

The Pilot agreed that the report was clearand accurate. He also agreed with theconclusions mentioned in the report.

Details of Carabao 1

Previous name City of Dubai (1994)

IMO No. 7368736

Flag Singapore

Classification Society Germanischer Lloyd

Ship type Livestock Carrier

Owner Labroy Marine (Pte) Ltd. Singapore

Charterer Rooney Shipping & Trading Pty Ltd,Berrimah, NT.

Year of build 1974

Builder Haugesunds Slip A/S, Norway

Gross tonnage 1487

Net tonnage 634

Summer deadweight 1941.3

Length overall 69.73 m

Breadth extreme 13.21 m

Draught (summer) 5.312 m

Engine B&W Alpha 4SA 16 cylinder diesel

Engine power 1825 kW

Crew 15 Filipino