ChiefEngineer’sLog

Someone asked about interlock between MSB and ESB testing onboard vessels. The procedure is quite simple but requires attention in order to prevent total power loss during test. In this procedure the bus tie breaker (located normally in ECR and EG’s room) need to be manually open and the emergency switchboard will black out. The emergency generator will start automatically and the generator ACB will close to feed the emergency generator. To return to the normal mode, the tie breaker must be manually closed and emergency generator ACB will open and generator will top automatically. The same test can be performed by turning the E/G SEQ TEST switch, located at the emergency switchboard, inside the emergency generator panel, to the ENG & ACB position. The bus tie breaker will receive an open command. However, during live test in presence of a surveyor or PSC officer , they will always ask to manually trip the tie breaker.

Moreover, the US Coastguard requires each transfer pipe system on board vessel to be tested under static liquid pressure at least 1.5 times the maximum allowable working pressure annually. This is best achieved by using the FO transfer pump to fill bunker lines up to the manifolds (with fuel oil), purge the lines via manifold valves , then build the pressure in the lines as required (operating parameters should be available in the bunker plan, or the vessel may be guided by pipeline material pressure rating).

Someone asked me to write a post about bunker line hydrostatic pressure test. It is important to know that bunker line needs to be pressure tested on a yearly basis and this is done normally at a pressure of 110 % than the relief valves opening pressure. Obviously, in order to do this it is required that the relief valve is removed and line blanked off. The pressure should be kept for about 15 min and line to be checked for any leaks. However at every vessel special survey, which is normally carried out during dry docking, it is required to perform an hydrostatic test of the bunker line and a certificate will be issued accordingly. Hydrostatic test is a test conducted by filling a space with a liquid to a specified head. Unless other liquid is approved, the hydrostatic test is to consist of filling a space with either fresh water or sea water, whichever is appropriate for the space being tested.

Cargo holds smoke detection system. Yet another very important equipment onboard who needs to be regularly tested for proper functioning is usually ignored by many engineers unless there is an alarm or malfunction on it. The system must be regularly checked and tested by simulating a real alarm, checking the free movement of the 3-way valves, checking the hoses integrity, the suction fan’s (especially the motors), cleaning the measuring tubes and cells, regularly checking the lines for free passage etc.

The treatment of boiler and cooling water implies the disposal of dissolved gases (will prevent corrosion), removal of Ca & Mg salts, boilers blow down, deposits removal etc.

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