The UK MAIB in one of its latest edition Safety Digest cases highlights lessons learned concerning a collision between a dredger and a yacht.
The incident:
It was a fine sunny day with excellent visibility when a dredger collided with a yacht. The yacht suffered catastrophic damage and sank with loss of life soon afterwards. The dredger was employed on a major dredging and reclamation project in a port.
It was a modern and well equipped ship with a range of navigation aids, including 3cm and 10cm ARPA radar, both of which were operational at the time of the accident. In common with many dredgers of its type, the ship was fitted with discharge equipment on its bow which, although complying with legal requirements, caused a blind sector directly ahead when viewed from the bridge conning position.
The chief officer and second officer were on watch on the bridge. The chief officer, who held a pilotage exemption certificate for the port, had the con, and the second officer was engaged in completing paperwork. The chief officer planned to follow his normal route out of the port, staying in the main channel up to a pre-determined point, then altering course to starboard to leave the channel, and setting a course for the designated dump site, for the vessel’s cargo of dredge spoil.
Having arrived at the pre-determined point in the channel, the chief officer altered course to starboard towards the dump site without either he or the second officer noticing a yacht that was now about 1.5 miles dead ahead.
On completing his paperwork, the second officer requested permission to leave the bridge to conduct some safety routines on deck. The chief officer agreed to this request, and the second officer left the bridge with the yacht now at a range of about 0.4 mile and still dead ahead.
The chief officer saw the top of the yacht’s mast very close and directly ahead of the bow seconds before the vessels collided. Following the collision, he raised the alarm and notified the harbour authority. The ship’s rescue boat was launched shortly afterwards and recovered the yacht’s skipper from the water. However, the second person on the yacht was unable to escape before the yacht sank soon after the collision.
Lessons Learned
1.Maintaining a proper lookout by all available means, in accordance with Rule 5 of the COLREGs, is essential. The dredger’s OOWs were not doing so. Neither of them identified the yacht in sufficient time to be able to take avoiding action despite the fine weather, excellent visibility and operational radar. Recorded evidence has shown that the yacht was clearly visible on at least one of the dredger’s radar displays for at least 12 minutes prior to the collision.
2. In this case, there was a blind sector directly ahead of the dredger’s conning position. Watchkeepers need to take full account of known blind or shadow sectors caused by the design characteristics of their particular vessel, and adjust their watchkeeping practices accordingly. Resist the temptation to remain in one place on the bridge. Move around frequently.
3. Local harbour regulations required the dredger’s bridge to be manned by two people. In this case, the second officer was engaged in other tasks and, while on the bridge, he was not keeping a lookout. It is all too easy in today’s busy world to become distracted and to prioritise what can erroneously be perceived to be more important jobs. Despite alternative crew being available to keep a lookout, none was requested to relieve the second officer before he left the bridge. Neither the chief officer nor the second officer valued having two people on the bridge. Do you?
4. Prior to making any alteration of course, the prudent mariner should ensure that the intended course is clear by scanning ahead, both visually and by radar. In this case, the dredger was required to keep out of the way of the yacht. However, as a stand-on vessel, the yacht had an option of taking early avoiding action as soon as it became apparent to the yacht’s skipper that the dredger was not keeping clear.
In altering course to starboard out of the channel, the dredger’s chief officer made a series of small alterations which, although not contributory to this accident, would have been difficult for other vessels to visually detect.
Source & Image credit: UK MAIB
