Ship maneuvering on approach to a lock: power loss, poor communications and design

30th June 2016

Ship maneuvering on approach to a lock: power loss, poor communications and design

Initial Report

This article outlines a pilot’s experience on approaching a lock. Slow response to his order for astern power, poor communication and ship design issues all come to light.

What did the reporters tell us?

Whilst manoeuvring a large pure car carrier (PCC) into a lock, with the stern tug at 100% arresting power, more deceleration was needed. An astern engine order was given, but the vessel was slowing very slowly. The pilot was not told that the main engine had failed to start twice. At this point the Master, rather distraught, asked if the after tug was pulling. In response to a direct question, the pilot was then informed that there was a problem with the engine. The pilot took emergency steps to stop the vessel by laying her against the rubber coping fenders to act as a friction brake. At this point the main engine started astern and the vessel was stopped and moored. Wind at the time was well under the limiting speed for sailing. The ship’s high minimum speed was another potentially complicating factor. Visibility along the side of the ship was limited, and communications across the bridge difficult. The distance from centre line to bridge wing was of the order of 16 metres, and key instruments at the conning position were in three different positions.

What did the ship’s operators tell us?

For environmental reasons newer electronic engines have reduced fuel injection when starting up. If the engine misfires, it will automatically try again after 10 seconds with a slightly increased fuel injection. According to the company’s internal report, that is what happened in the lock and is normal. When proceeding at a low speed in narrow waters, this can of course be seen as a potential hazard; the standard procedure is therefore to have the thruster(s) ready for use in addition to sufficient tugboat assistance (in this case three in total). The company believes that both of these requirements were fulfilled. All three control positions (centre line and wings) are identical. With a beam of 36.5 metres, this particular vessel follows the ‘New Panamax’ standard. The company forwards the vessels’ details to agents in good time before arrivals.

The lessons to be learnt

Main propulsion. Modern propulsion systems with potential in-built delays and high minimum speeds present considerable complication and risk when manoeuvring at close quarters (for example approaching locks). The characteristics need to be carefully briefed and understood between Master and pilot in advance. A propulsion test should be part of pre-arrival checks. Communication. Very wide bridges complicate verbal communication; a procedure for conning and use of bridge wing control positions needs to be agreed and tested well in advance. This would have facilitated an alert to the pilot about the engine’s failure to engage astern.

The master-pilot information exchange is a crucial factor; see ‘CHIRP suggests’ below. Visibility. Lack of clear visibility down the ship’s sides was a serious limiting factor for the pilot. He and the Master found they had to move rapidly between positions. Ship design. The reporter makes strong points in relation to visibility and communication on modern very large ships, minimum ships’ speeds, and the ‘engine fail start’ dimension which (though explained by the 3rd party) represents a major risk in close manoeuvring. Failure to share best practice and ship design implications are also suggested.

CHIRP suggests

Give high priority to timely pre-arrival checks (control position change overs, and machinery control for example), and to a comprehensive master-pilot exchange covering procedure, the sequence of events, engine control and limitations, the overall plan, recent defects and action in the event of potential failures. User input in design, and the practice of ships’ crews standing by on build, have in many areas been diluted; at the very least experienced deck officers including pilots should be involved in the design of conning positions, especially in major shipyards which build standard design ships. This should embrace issues such as visibility from bridge wings, and – more broadly – machinery control.

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