How Do Ships Work

The Basics

Basically, you just get in the Captain’s Chair, turn the key to start the engine. Then use the gas and break pedals as needed… …If only it were that simple. Although there are some Mates that seem to think that is the case. The truth could not be further from that statement. In fact, it can take up to a week to get a ship ready to turn the prop (aka propeller or ‘screw’). This article will go over the 30,000 ft. view (with some details) about how ships get prepped and ready to answer bells (yes, actual bells) when it is time to get underway, so keep reading! For more on maritime careers, see our guide on how to become a merchant mariner.

First Things First

To start things off, below is a list of SOME of the major systems required for a ship to operate. These systems will differ from ship to ship depending on what type of propulsion the ship has (Diesel Engines, Gas Turbines, or Steam Propulsion), so this list is just a general overview that most ships will have:

Electrical Systems – (The Brains) - An electrical power generation system is at the top of this list. Although it is not the only critical system a ship will have, almost all the other systems on modern ships depend, directly or indirectly, on being provided with electricity, so I’ve put this at number 1 on the list.
A Propulsion Systems – (The Muscles) - As stated above, all ships will have some variant of one of these three types of systems (Gas Turbine, Steam, or Diesel Engines) to propel the ship as needed. Obviously, this system is needed to move the ship.
Lubricating Oil Systems – (Bodily fluids?) - Ships are basically all metal and rely heavily on things rotating to make the ship work such as the propeller shaft, pumps, engines…etc. Without lubricating oil, to separate the rotating elements of, say, one of the propeller shaft bearings, the metal parts would just rub against each other and create so much heat that they would melt or become deformed and not work properly, rendering the ship unable to move. For more on ship maintenance, see our article on ship maintenance periods.
Fuel Oil Systems – (Calories/Food) - Ships need fuel just like anything else. Therefore, obviously the fuel system is a major part of any ship. Fuel is consumed by a ship in the same way a human consumes calories, just on a much larger scale. For more on this, see our article on ship fuel systems.
Air Conditioning - Ships have what’s called a ‘Chiller’ or AC Chiller to keep things cool. A Chiller is essentially a large HVAC (Heating, Ventilation, and Air Conditioning) system for the ship. While the Chillers do serve to keep the house (where the crew resides) cool, the primary purpose of the HVAC system is to keep the electronic equipment cool. Modern ships have sensitive electronic equipment that require temperatures to be maintained below a certain level to work properly. Therefore, they must be provided with cool air in order to remove the heat from the machinery and electronics.
Steering Gear System - The steering gear system is what controls the ship’s rudder. Obviously, this is necessary for the ship to be able to get from point A to point B, much like the steering wheel on a car.

These are a few of the major systems that are required to be up and running to get the ship moving from point A to point B. Some other ship systems include:

Fire Systems - to include all the pumps, fire detectors, Halon, CO2 systems..etc.
Water Systems - to create potable water for consumption by the crew and distilled water for use in ship’s machinery.
Cooling Water Systems - To remove heat from the various pieces of equipment.
Refrigeration system - to keep the food cold.
Sewage System

All these systems can be broken down into smaller systems as well. If you’re interested in working with these systems, see our guide on what do marine engineers do.

Remember, a ship basically operates as a floating city, with some extra bells and whistles required to make it float and move through the water. Again, in this article I will go over some basic steps to get a ship up and running and ready to go, but remember that people go to school for years to learn this process, so this will just be the tip of the iceberg.

Power

First and foremost, the electrical system needs to be up and running. If a ship is pier-side, there may be what is called ‘shore-power’ provided to the ship via cables on the pier. Shore-power is just what the name indicates, power that comes from a the pier (via a shore-side power generation plant).

If a ship is on Shore-power, that power will be provided to the ship via a series of connections that the cables will plug into, usually somewhere relatively easily accessible from the pier. The power will then be transferred down to the main electrical switchboard for use throughout the ship.

If the ship is not on shore-power, the ship will be providing its own power (aka Ship’s Power). If on ship’s power, the ship’s electrical generators will be online and providing power to the ship’s electrical distribution system.

Ships are required to have an emergency power system, which is often a smaller diesel generator that is able to provide enough power to keep the ship’s critical systems running. This Emergency Diesel Generator (EDG) as it is known, also automatically starts, and puts itself on the ‘bus’ (electrically connects itself) should the regular switchboard not have power for any reason. The term ‘on the bus’ is referring to the electrical ‘bus’, which is essentially the physical conduit where all the electricity is flowing.

Ship’s do lose power (some more than others depending on the crew and the maintenance of the engineering plant) so having a reliable emergency power system is critical, and mandatory. In fact, there are many systems that are required by the regulatory agencies to be in good working order for a ship to get underway, and this, unsurprisingly, is one of those systems.

Propulsion

Ultimately, a ship’s propeller needs to be turning for the ship to be able to go anywhere, right? If you haven’t been on a ship before, you may not realize what it takes to get this to happen. As I said in the beginning of this article, that process can take up to a week (for a Steam Ship) or a few hours (for a Diesel Ship). For detailed information about marine diesel engines, see our article on marine diesel engines.

Steam Ships

A Steam Ship takes the longest to get up and running. Why is that? Well, because of the high pressures and heat that is produced by a Steam Plant…Let me explain. We’ve all heard of a Boiler, right? Well, Steam Ship’s use Boilers to create high pressure steam, which is then travels via a pipe to a steam turbine which is connected (via gear sets) to the ship’s propeller, therefore turning the propeller.

Sounds easy right? It’s the same principle as boiling a big pot of water, but the scale on which it happens is a lot greater. The heat and pressure produced, if not done correctly, could eventually cause damage to the boiler and piping system at best, or could result in an explosion of the boiler at worst. Therefore, the boiler and piping needs to be heated up gradually (the boiler especially) according to the manufacturer’s specifications.

This process involves lighting the burners for the boiler for short periods of time for days straight until the temperatures and pressures inside the boiler reach certain levels. As the boiler heats up over a period of days, the piping system is drained of water (steam left in the pipes that condensed into water) and also heated gently until up to operating temperature as to not cause an unacceptable amount of thermal stress or shock to the system.

Once everything is up to temperature and pressure and steam is being applied to the Steam Turbine, the turbine must be rotated every few minutes until the ship is ready to go so as not to be subjected to warping while the hot steam is being applied. Don’t worry, the Revolutions Per Minute of the propeller are limited during this time to be as little as possible to keep the ship from actually moving before it is supposed to.

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