Preliminary report


Published: 22 November 2017

Sequence of events

On 30 September 2017, at about 0025 Eastern Standard Time,[1] the Australian Border Force cutter Roebuck Bay (ABFC Roebuck Bay) grounded on Henry Reef in the Great Barrier Reef, Queensland. The cutter was on a passage from Saibai Island in the Torres Strait Islands archipelago bound for Lizard Island, located about 71 NM south-east of Cape Melville (Figure 1). The cutter sustained significant damage to the keel, stabiliser fins and propellers, with water ingress in the forward and freshwater void spaces. There were no reported injuries or pollution.

Figure 1: Section of navigational chart Aus 4620 showing location of grounding

Figure 1: Section of navigational chart Aus 4620 showing location of grounding. Source: Australian Hydrographic Service, annotated by the ATSB
Source: Australian Hydrographic Service, annotated by the ATSB

The passage plan, based on a previously used plan, was prepared by ABFC Roebuck Bay’s navigation officer and presented to the commanding officer (CO) for approval on 26 September, while at anchor at Saibai Island. The plan initially consisted of a passage from Saibai Island directly to Cairns with several operational taskings en-route. The CO reviewed the passage plan and made a few amendments to the route, which included shifting one waypoint about 0.2 NM south of its original position and another about 1 NM west of its original position (Figure 2). The amended waypoints were designated waypoint 19 (WP 19) and waypoint 20 (WP 20) in the passage plan’s waypoint list. The CO also advised the navigation officer that the passage was to be split into two legs with a brief stop at Lizard Island before continuing on to Cairns for the end of the patrol. The navigation officer reviewed the amendments to the passage plan and saved the routes on the electronic chart display and information system (ECDIS). Subsequently, on 28 September, a passage plan briefing was conducted to brief the cutter’s heads of department and officers of the watch on the details and requirements of the proposed passage.

Figure 2: Image from ABFC Roebuck Bay's ECDIS

Figure 2: Image from ABFC Roebuck Bay’s ECDIS display showing the previously used route and the amended route based on the amended waypoints WP 19 and WP 20
Source: Australian Border Force, annotated by the ATSB
Image from ABFC Roebuck Bay’s ECDIS display showing the previously used route and the amended route based on the amended waypoints WP 19 and WP 20.
Source: Australian Border Force, annotated by the ATSB

On 29 September, at about 0953, ABFC Roebuck Bay departed Saibai Island with a maximum draught[2] of about 2.2 m. The cutter’s bridge watchkeeping teams comprised an officer of the watch (OOW) and an assistant officer of the watch (AOOW) maintaining 4 hour watch rosters.

At about 2345 that night, the OOW and AOOW for the next watch (between 0001 and 0400 on 30 September) arrived on the bridge and shortly after took over the watch. The OOW on the 0001 to 0400 watch also happened to be the cutter’s navigation officer. The night was partly cloudy with visibility recorded as 6 to 8 NM and the wind from the south-east at 20 knots with a 1 m sea and swell.

At about 0004 on 30 September, the OOW altered ABFC Roebuck Bay’s heading[3] to 132° at WP 18. A few minutes later, at 0012, the heading was altered to 107° at WP 19. At about 0017, as ABFC Roebuck Bay approached WP 20 at a speed of about 16 knots, the OOW altered the cutter’s heading to 194°.

At about 0025, the bridge team felt a bump and a shuddering sensation before ABFC Roebuck Bay abruptly grounded and came to a complete stop. The OOW and AOOW were thrown out of their seats onto the bridge display screens in front of them. The general emergency alarm was sounded as the CO arrived on the bridge having been woken by the impact of the grounding. The crew was mustered, damage control measures initiated and emergency communications commenced.

A number of vessels provided support and assistance to ABFC Roebuck Bay over the following days.

ABFC Roebuck Bay was eventually re-floated at about 1830 on 1 October with assistance from the Australian Maritime Safety Authority’s emergency towing vessel Coral Knight. The cutter was towed to Cooktown where additional damage control equipment was obtained and a salvage specialist embarked. ABFC Roebuck Bay was then towed to Cairns arriving at the anchorage on 4 October. At about 0612 on 5 October, Coral Knight’s tow line was slipped and ABFC Roebuck Bay was taken under tow by harbour tugs. ABFC Roebuck Bay arrived at the Norship Marine yard in Cairns at about 1000 on 5 October and was subsequently lifted out of the water.

Preliminary observations

The ATSB attended ABFC Roebuck Bay at the shipyard in Cairns to collect electronic and physical evidence. The ATSB has also interviewed several Australian Border Force (ABF) officers with navigation and watchkeeping responsibilities on board ABFC Roebuck Bay.

Preliminary observations indicate that ABFC Roebuck Bay grounded on Henry Reef, a charted feature. ECDIS data showed that, at the time of the grounding, ABFC Roebuck Bay was about 15 m to port of the planned track, which was well within the passage plan’s cross track error[4] limit of 100 m for that leg of the passage. The cutter’s GPS, echo sounder and radar all appeared to be operating normally.

The CO, navigation officer and other officers of the watch on board ABFC Roebuck Bay were all appropriately qualified and had completed the required generic and type-specific ECDIS training.

Continuing investigation

The investigation is continuing and will include consideration of:

  • ABF navigation and passage planning procedures
  • analysis of ECDIS settings and data
  • use of ECDIS by ABF vessels
  • conduct and effectiveness of ECDIS training
  • understanding of chart accuracy and compilation.


The information contained in this update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this update. As such, no analysis or findings are included in this update.



  1. Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.
  2. Draught is the vertical distance between the keel of the ship and the waterline at any position.
  3. All ship’s headings in this report are in degrees by gyro compass with negligible error.
  4. Cross track error: The distance the ship is off its intended track.