A vessel requires fluids such as fuel oil, diesel oil, lube oil, hydraulic oil, drinking water, fresh water, ballast water, etc for its operations on a voyage. These fluids are stored in various tanks at different locations on the ship.
The size, quantity and location of the storage tanks depends on some factors such as:
- Type of ship
- Size of ship
- Propulsion system
- Nature of fluid
- Type of auxiliary engines and machineries
- Voyage plan
To ensure ship stability, tanks are evenly distributed across the the ship from forward to aft and port to starboard. Here's a list of tanks on a ship for fuel, lube oil and water:
Fuel & Diesel Oil Tanks:
Bunker tanks are used to stored fuel or diesel oil transferred during bunkering operations. It has big capacity for storage and it is usually located outside the engine room. bunker tanks are generally a wing or double bottom tank.
Treated oil are stored in service tanks onboard ships and transmitted for use to the main engine, auxiliary engine and boilers. It could be two or more in number. Service tanks forms part of the bulkhead of the engine room.
Settling tanks form part of the bulkhead of the engine room. Oil from the bunker tank is normally transferred to settling tank. Diesel oil settling tank can be located as double bottom tank in the engine room.
To avoid mix-up, tanks for Low Sulphur Fuel Oil (LSFO) and Marine Gas Oil is segregated from other fuel oil.
Oil overflow from bunker tank is collected by over-flow tank. It is provided for both fuel and diesel oil system in the engine room. Return lines and leakages are also directed to overflow tank. It is common practice to use a single overflow tank for high and low sulphur system.
Emergency Generator Oil Tank
Fuel for emergency generator is supplied from a special dedicated oil tank. The capacity of the tank is specified by SOLAS regulation. The tank is located in the emergency generator room outside the main engine room.
Fresh Water (FW) Tanks
Clean water for use in accommodation, engine room and deck is stored in fresh water tanks. The tanks could be two or more depending on the size of the ship and type (cargo, cruise, etc). Fresh water can be loaded at port or produced with fresh water generator (FWG).
Boiler Tanks: Distilled Water Tank, Boiler Feed Water Tank, Cascade Tank
The boiler used on a ship required distilled water to produce steam. Water from Fresh Water Generator (FWG) is stored in distilled water tank for the boiler usage. The boiler system has another tank to receive the distilled water from the distilled water tank called Boiler Feed water tank.
Water from the boiler feed tank is pumped to cascade tank or hot well for treatment. Water from steam heating system is collected at the cascade tank as well.
Ballast Water Tanks
Ballast water tanks are distributed across the ship for ballasting and de-ballasting purpose to achieve ship stability. Depending on vessel type, double bottom tanks are generally located outside the engine room.
Lubricating Oil Tanks
Main Engine Oil Tank: Cylinder Oil Tank, Crankcase Oil Tank, Turbocharger Oil Tank
The oil used inside the combustion chamber between the piston and the liner is stored in the ME cylinder oil tank. Crankcase oil has its tank(s). Lube oil system doesn't require service or settling tanks, the oil is pumped directly from the main tank.
A separate lube oil tank is provided for engines that has a turbocharger system with forced lubrication.
Auxiliary Engine Lubrication Oil Tank
Auxiliary engine are 4 stroke engines and it doesn't require cylinder lube oil. The auxiliary engine main lube oil is stored in auxiliary engine lube oil tank. The size and quantity of tank depends on the ships specification.
Lube Oil Daily Tanks
A daily tank is provided for the main engine cylinder oil with capacity of the cylinder daily consumption in the engine room. Same is provided for turbocharger where applicable.