How do Ship's 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!

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.
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.
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

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).

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.

Diesel Ships

Getting a ship with Diesel Engine propulsion is still somewhat of a process, but it is a lot less involved of a process than a that of a Steam Ship. I will start by explaining that pretty much every marine (shipboard) diesel engine has what is called a jacket water system and a lubricating oil system.

The Jacket Water system serves to remove heat from the engine block (the metal part of the engine). It does this by traveling through passages drilled into the engine block, where the heat is transferred to the water from the metal engine block. That heat is then removed ultimately in a heat exchanger (either by salt water or a lower temperature fresh water), where the Jacket Water is then recirculated to repeat the process and the temperature is regulated at a certain point.

The lubricating oil system does just what it says, it lubricates the parts of the engine where a metal surface is moving relative to another metal surface. This lube oil also gets hot during this process and is maintained at a certain temperature, just like the jacket water, the lube oil temperature is also regulated by a temperature regulator to maintain optimum temperature for the engine.

To get a Main Propulsion Diesel Engine up and running from a ‘cold iron’ status (where the engine is cold because it hasn’t been ran or heated). The first step is to turn on what is called the pre-lube pump. The pre-lube pump is a small pump that circulates the lubricating oil through the engine in order to maintain the oil film on the metal surfaces while the engine is not running.

The second step is to turn on the ‘Keep Warm’ system. The Keep Warm system consists of a small pump and heat exchanger that heats the engine’s cooling water and circulates it through the engine to keep the engine warm or heat the engine up if it is cold. This serves two purposes. The first is that it heats the metal engine block. The second step is that it heads the lube oil that is circulating through the engine. Once the lube oil is up to a stable temperature (set by a thermostat on the heat exchanger), that temp is maintained until the engine is ready to start.

The next step is to make sure that there is no fluid inside the actual cylinders. This is called ‘blowing-down’ the engine or ‘rolling’ it over. There are small valves coming directly from the cylinder that are open to the engine room. Those valves are opened before compressed air (Starting Air) is briefly applied to the engine (with the fuel system Locked and Tagged Out, of course) the engine then turns a few times while someone is standing by watching all these valves that are open (they are known as Air Cocks), making sure that no water is expelled, as this could indicate a crack or leak in the cylinder.

Note - The process of rolling an engine over is typically done at least once a day (by the Generator 3rd Engineer) for the Diesel Generators, to make sure they are ready to go should the Online generator (if there is one) trip Offline.

Once the above processes are completed and all the auxiliary systems for the engine are ready to go (fuel, lube oil, cooling water…etc), the engine is then started, the operating temperatures are then allowed to come up until they are stable. The engine is ready to be clutched in and turn the propeller.

Gas Turbine Ships

It has been a while since I’ve been on a Gas Turbine ship, but I will share with you what I know off the top of my head without having a manual or procedure in front of me. A ship that has a gas turbine propulsion system often takes a minimal amount of effort to get underway. This is because gas turbines pretty much come as package units.

Gas turbines themselves are complex pieces of machinery with thousands of precision machined parts. However, just like diesel generators and steam turbines, they are connected to the propeller shaft via a set of gears to reduce the speed of the propeller shaft to the optimal speed ranges according to the design of the propeller. Therefore, all that is needed to get a ship moving with gas turbine propulsion is for the turbine to be started according to the manufacturer’s procedures, clutch-in, and bump up the turbine speed!

Recap

In this article I went over some of the basic shipboard systems that are present on pretty much any ship. This is not an exhaustive list by any means, and the other systems not mentioned above are also very important. I just wanted to provide a bare-bones idea of what type of engineering systems ship’s have. In a later article, we will go into greater detail on each one of these systems and a few ins-and-outs of each one. Also know that the above steps listed to get things going are a lot more involved in real-life, but they serve as a good overview.