| Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation. |
What happened
On 3 August 2021, a 63 m landing craft prepared to depart Masons Wharf in Smiths Creek, Cairns, where the craft was berthed starboard side alongside with a patrol vessel berthed immediately astern and downstream of it (Figure 1, position 1). To proceed to sea, the landing craft needed to turn downstream off the wharf and then sail out of the creek.
Figure 1: Sequence of events
Relative size and position of vessels in diagram are approximate indications only
Source: Maritime Safety Queensland
At 1615 local time, the landing craft cast off from the wharf. The tide was flooding with high tide predicted at 1925. From the landing craft’s navigational bridge, the master initially manoeuvred the craft about 8 m laterally off the wharf. The master then altered the craft’s heading slightly to starboard before operating astern propulsion on both main engines. This plan involved allowing the flooding tide to act on the craft’s starboard quarter to assist with the manoeuvring away from the wharf as it came astern (Figure 1, position 2).
Moments later, the master observed that the south-easterly wind acting on the landing craft’s port side was counteracting the effect of the tidal stream, making it difficult to manoeuvre away from the wharf and the patrol vessel as planned. Consequently, in an effort to drive the craft’s stern further into the channel where it could be safely turned around, the master increased astern propulsion (Figure 1, position 3).
At that time, a crew member stationed aft with a radio began reporting the distance from the creek’s eastern shoreline, thickly wooded with mangroves, to the master. Another crew member with a radio was stationed forward to report clearances from the bow. As the radios of the master and crew were on the same simplex frequency,[1] transmissions from aft were interfering with those from forward. Consequently, the master resorted to making his own visual appraisal of the clearance from the patrol vessel ahead and remained focused on executing the turn, but not the decreasing clearance from the mangroves being reported. Shortly after, the landing craft’s stern ran into the mangroves (Figure 1, position 4 and Figure 2) before the master took action to manoeuvre clear and sail down the creek. The landing craft was found to remain in good working order afterwards and proceeded on its voyage.
Figure 2: Landing craft running into mangroves
Source: Landing craft operator
Safety action
The landing craft’s manager advised that as a result of this occurrence, a review of mooring procedures has been commenced, including communication protocols between crew members during operations.
Safety message
This occurrence highlights the importance of appropriate planning and risk assessment prior to vessel manoeuvring operations while also underscoring the importance of effective onboard communication procedures. These measures are relevant even for familiar, routine operations. A comprehensive appraisal might include an assessment of wind, tide and sea conditions in relation to the proximity of navigation hazards and the available manoeuvring room.
About this report
Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report and allow for greater industry awareness of potential safety issues and possible safety actions.
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