How to keep a ship running
Our vessels are equipped with an adequate engineering plant to keep them self-sufficient at sea for up to 55 days. This includes providing all crew and scientific staff with all necessary requirements for them to complete essential research at sea. This ranges from powering the vessel through the water from A to B, right through to ensuring comfortable living conditions on board whilst operating in extreme conditions.
The ship’s engineering department are responsible for generating the electricity and propulsion needed to be able to sail and work on the vessel. They also provide the vessel with all the other amenities needed for a successful and comfortable scientific cruise. These items include:
- Hot / cold drinking water
- Hydraulic power for the overside handling systems
- Waste water disposal and treatment
- Heating, ventilation and air-conditioning
- Refrigeration for cold and frozen provision stores
- Garbage compaction, storage and incineration
Power
The ships have a Diesel-Electric Propulsion system, which means a number of diesel-generators create electricity to supply large electric motors which power the ship’s propellers and thrusters. Below an overview of the system as found on board RRS James Cook. The power plant on this vessel includes four diesel generator sets of approximately 2860HP each, which feed a main 690V switchboard. Further is the power distributed to 440V switchboards, 230V switchboards and 110V switchboards through several transformers, for use on deck, labs, accommodation, and lighting etcetera.
The vessels also carry ample supplies of fuel and numerous types of lubrication oil to keep all engines and other machinery equipment well looked after for the duration of the trip. The vessel can carry up to about 900,000 litres (797,972 gallons) of fuel and about 11,300 litres (2,485 gallons) of engine lubrication oil and not least sufficient tools and spare parts to maintain the large number of equipment on board.
Propulsion
Apart from the two main propellers moving the vessel through the water, there are also 4 Thrusters which are used for manoeuvring in port and to keep the vessel at a position during scientific operations. This system is called Dynamic Positioning (DP) and is able to maintain an exact position in the water under challenging weather and sea conditions, using satellite navigation systems for positional reference. Here you can see one of the RRS James Cook’s main propellers and the Azimuth Thruster during her last dry docking:
Water
As one can imagine, fresh running water is an essential commodity on board a ship out at sea for over 50 days. The vessel can store up to 210 m3 (46,194 gallons) of fresh water in tanks which are normally filled in port prior to sailing. However, this quantity of water is only sufficient for about 2/3 weeks’ consumption. To make sure the vessel does not run out of water, she is fitted with vacuum evaporators. These evaporators boil water inside a vacuumed space, using engine cooling water as a heat source. By boiling the water under vacuum inside the evaporator body, the boiling point comes down enabling the engine cooling water to heat the seawater sufficiently to bring it to the boil. The evaporated steam is then condensed and drained off and pumped away as fresh water. Once the water has been pumped through a mineraliser filter and treated with a disinfectant, it is pumped to the on board storage tanks for distribution and use throughout the ship. Below an overview drawing, showing the principle of our on board evaporators, using engine cooling water as a heating medium.
