Tuesday, 26 June 2012

Watchkeeping

Watchkeeping
Watchkeeping 
The 'Round the clock' operation of a ship at sea requires a rota system of attendance in the machinery space. This has developed into a system of watchkeeping that has endured until recently. The arrival of 'Unattended Machinery Spaces' (UMS) has begun to erode this traditional practice of watchkeeping. The organisation of the Engineering Department, conventional watchkeeping and UMS practices will now be outlined.
 

The Engineering Department

The Chief Engineer is directly responsible to the Master for the satisfactory operation of all machinery and equipment. Apart from assuming all responsibility his role is mainly that of consultant and adviser. It is not usual for the Chief Engineer to keep a watch.
The Second Engineer is responsible for the practical upkeep of machinery and the manning of the engine room: he is in effect an executive officer. On some ships the Second Engineer may keep a watch. The Third and Fourth Engineers are usually senior watchkeepers or engineers in charge of a watch. Each may have particular areas of responsibility, such as generators or boilers.
Fifth and Sixth Engineers may be referred to as such, or all below Fourth Engineer may be classed as Junior Engineers. They will make up as additional watchkeepers, day workers on maintenance work or possibly act as Refrigeration Engineer.
Electrical Engineers may be carried on large ships or where company practice dictates. Where no specialist Electrical Engineer is carried the duty will fall on one of the engineers.
Various engine room ratings will usually form part of the engine room complement. Donkeymen are usually senior ratings who attend the auxiliary boiler while the ship is in port. Otherwise they will direct the ratings in the maintenance and upkeep of the machinery space. A storekeeper may also be carried and on tankers a pump man is employed to maintain and operate the cargo pumps. The engine room ratings, e.g. firemen, greasers, etc., are usually employed on watches to assist the engineer in charge.

The watchkeeping system
The system of watches adopted on board ship is usually a four hour period of working with eight hours rest for the members of each watch. The three watches in any 12 hour period are usually 12-4, 4—8 and 8-12. The word 'watch' is taken as meaning the time period and also the personnel at work during that period.
The watchkeeping arrangements and the make up of the watch will be
decided by the Chief Engineer. Factors to be taken into account in this matter will include the type of ship, the type of machinery and degree of automation, the qualifications and experience of the members of the watch, any special conditions such as weather, ship location, international and local regulations, etc. The engineer officer in charge of the watch is the Chief Engineer's representative and is responsible for the safe and efficient operation and upkeep of all machinery affecting the safety of the ship.
 
Operating the watch

An engineer officer in charge, with perhaps a junior engineer assisting and one or more ratings, will form the watch. Each member of the watch should be familiar with his duties and the safety and survival equipment in the machinery space. This would include a knowledge of the fire fighting equipment with respect to location and operation, being able to distinguish the different alarms and the action required, an understanding of the communications systems and how to summon help and also being aware of the escape routes from the machinery space.
At the beginning of the watch the current operational parameters and the condition of all machinery should be verified and also the log readings should correspond with those observed. The engineer officer in charge should note if there are any special orders or instructions relating to the operation of the main machinery or auxiliaries. He should determine what work is in progress and any hazards or limitations this presents. The levels of tanks containing fuel, water, slops, ballast, etc., should be noted and also the level of the various bilges. The operating mode of equipment and available standby equipment should also be noted.

At appropriate intervals inspections should be made of the main propulsion plant, auxiliary machinery and steering gear spaces. Any routine adjustments may then be made and malfunctions or breakdowns can be noted, reported and corrected. During these tours of inspection bilge levels should be noted, piping and systems observed for leaks, and local indicating instruments can be observed.
Where bilge levels are high, or the well is full, it must be pumped dry. The liquid will be pumped to an oily water separator, and only clean water is to be discharged overboard. Particular attention must be paid to the relevant oil pollution regulations both of a national and international nature, depending upon the location of the ship. Bilges should not be pumped when in port. Oily bilges are usually emptied to a slop tank from which the oil may be reclaimed or discharged into suitable facilities when in port. The discharging of oil from a ship usually results in the engineer responsible and the master being arrested.

Bridge orders must be promptly carried out and a record of any required changes in speed and direction should be kept. When under standby or manceuvring conditions with the machinery being manually operated the control unit or console should be continuously manned.  Certain watchkeeping duties will be necessary for the continuous operation of equipment or plant—the transferring of fuel for instance.

In addition to these regular tasks other repair or maintenance tasks may be required of the watchkeeping personnel. However no tasks should be set or undertaken which will interfere with the supervisory duties relating to the main machinery and associated equipment.  During the watch a log or record will be taken of the various parameters of main and auxiliary equipment. This may be a manual operation or provided automatically on modern vessels by a data logger.  A typical log book page for a slow-speed diesel driven vessel is shown in Figure 17.1.

The hours and minutes columns are necessary since a ship, passing through time zones, may have watches of more or less than four hours.  Fuel consumption figures are used to determine the efficiency of operation, in addition to providing a check on the available bunker quantities. Lubricating oil tank levels and consumption to some extent indicate engine oil consumption. The sump level is recorded and checked that it does not rise or fall, but a gradual fall is acceptable as the engine uses some oil during operation. If the sump level were to rise this would indicate water leakage into the oil and an investigation into the cause must be made. The engine exhaust temperatures should ail read about the same to indicate an equal power production from each cylinder. The various temperature and pressure values for the cooling water and lubricating oil should be at, or near to, the manufacturer's designed values for the particular speed or fuel lever settings. Any high


outlet temperature for cooling water would indicate a lack of supply to that point.Various parameters for the main engine turbo-blowers are also logged. Since they are high-speed turbines the correct supply of lubricating oil is essential. The machine itself is water cooled since it is circulated by hot exhaust gases. The air cooler is used to increase the charge air density to enable a large quantity of air to enter the engine cylinder. If cooling were inadequate a lesser mass of air would be supplied to the engine, resulting in a reduced power output, inefficient combustion and black smoke.

Various miscellaneous level and temperature readings are taken of heavy oil tanks, both settling and service, sterntube bearing temperature, sea water temperature, etc. The operating diesel generators will have their exhaust temperatures, cooling water and lubricating oil temperatures and pressures logged in much the same way as for the main engine. Of particular importance will be the log of running hours since this will be the basis for overhauling the machinery.

Other auxiliary machinery and equipment, such as heat exchangers, fresh water generator (evaporator), boiler, air conditioning plant and refrigeration plant will also have appropriate readings taken. There will usually be summaries or daily account tables for heavy oil, diesel oil, lubricating oil and fresh water, which will be compiled at noon. Provision is also made for remarks or important events to be noted in the log for each watch.

The completed log is used to compile a summary sheet or abstract of information which is returned to the company head office for record purposes.

The log for a medium-speed diesel driven ship would be fairly similar with probably greater numbers of cylinder readings to be taken and often more than one engine. There would also be gearbox parameters to be logged.

For a steam turbine driven vessel the main log readings will be for the boiler and the turbine. Boiler steam pressure, combustion air pressure, fuel oil temperatures, etc., will all be recorded. For the turbine the main bearing temperatures, steam pressures and temperatures, condenser vacuum, etc., must be noted. All logged values should correspond fairly closely with the design values for the equipment.

Where situations occur in the machinery space which may affect the speed, manoeuvrability, power supply or other essentials for the safe operation of the ship, the bridge should be informed as soon as possible. This notification should preferably be given before any changes are made to enable the bridge to take appropriate action.

The engineer in charge should notify the Chief Engineer in the event of any serious occurrence or a situation where he is unsure of the action to take. Examples might be, if any machinery suffers severe damage, or a malfunction occurs which may lead to serious damage. However where immediate action is necessary to ensure safety of the ship, its machinery and crew, it must be taken by the engineer in charge.

At the completion of the watch each member should hand over to his relief, ensuring that he is competent to take over and carry out his duties effectively.

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