Παρασκευή 2 Οκτωβρίου 2020

MAIB UK Investigation Reports / Lessons Learnt (02/2020)

 1-ECDIS is not an Alarm Clock

Narrative

It was a fine summer night and a live fish carrier was on passage; the bridge was manned by the OOW and an AB lookout. It was still dark at 0430 when the AB left the bridge to prepare painting materials for the next watch.

Thereafter, the OOW was alone and sitting in the bridge chair. The OOW did not feel tired but must have drifted off to sleep as he was suddenly woken by the ECDIS safety depth alarm indicating that the water depth was less than 10m.

The OOW applied astern power and turned to port in an attempt to avoid shallow water. But it was too late, and the vessel was still underway at 4kts when it grounded (see figure). The master was called to the bridge, and an initial assessment found no internal damage. The crew refloated the vessel using its own power around 30 minutes after the grounding and headed for harbour. Once the vessel was within mobile phone range, the coastguard was informed. An inspection by divers found some minor damage and the vessel proceeded to dry dock for repairs.

The Lessons

1. An alarm is only of value if it provides sufficient warning for the OOW to make sense of what is wrong and take action accordingly. In this case the depth alarm came too late to be effective as the seabed shelved steeply around the island and the water depth decreased rapidly. Neither the ECDIS off-track alarm, which would have alerted the OOW to the missed course alteration, nor the BNWAS, which would have alerted the crew to the inactivity on the bridge, had been set. Had either alarm sounded there might have been sufficient time to avoid the grounding.

2. There have been many incidents caused by lone watchkeepers falling asleep on the bridge. After a previous grounding incident under similar circumstances, the company involved in this case had required that a lookout be posted in the hours of darkness. When the lookout left the bridge to perform other duties while it was still dark the OOW was left alone and vulnerable to falling asleep.

3. Fatigue can creep up on you. Even if you do not feel tired it is important to recognize that falling asleep is a real risk when working at night, particularly in the pre-dawn hours where circadian rhythms mean the body is most primed for sleep.

4. Alerting the coastguard should be one of the first actions after an incident – not the last. Although the vessel was refloated without assistance, an early call to the coastguard would have been invaluable had the situation escalated. The ship was within VHF coverage and could easily have communicated with the coastguard without delay.

2-A Splash of Danger

Narrative

The crew of a cargo vessel were preparing for departure from their regular port, and a tug was connected at the bow and waiting to assist. All the mooring lines were still fast and the bosun was preparing to single up the forward lines, which would have included releasing the mooring winch brakes. However, instead of releasing the mooring winch brakes, the bosun released the port anchor windlass brake, inadvertently freeing the port anchor, which dropped into the water extremely close to the tug (Figure 1). There was no damage to either vessel, and the departure proceeded without further incident after the port anchor had been retrieved.

The Lessons

1. The brake release handles for the mooring winch and anchor windlass were next to each other (Figure 2). Tis arrangement is not unusual but does introduce the risk of inadvertent release of the wrong handle. On this vessel, the crew had painted the anchor release red to assist with distinguishing between the handles. Nevertheless, when preparing to depart from harbour the bosun operated the wrong handle, resulting in the accidental release of the anchor. This occurred because in all other respects the anchor was ready for letting go, removing any safety barrier to prevent inadvertent release.

2. The bosun was experienced and familiar with the mooring and anchor arrangements; it was daylight, good weather conditions and the crew were rested, so fatigue was not a factor. Therefore, there were no clearly identified causal factors for the bosun’s erroneous action. Events like this can happen, and it highlights the need for carefully following procedures, teamwork and maintaining high levels of supervision when working on deck. 

3. The anchor fell extremely close to the waiting tug. Had the tug been directly underneath the anchor with crew on deck, this accident could have had severe consequences. Tis serves as an excellent reminder of the hazards that exist for tugs, workboats or line handling boats when operating in close proximity to larger vessels.







 

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