While reclining on the deck, enjoying the muffled scream of the ocean as it runs along the hull’s side it is possible to be excused for forgetting that you are on the top of an engineering monster. In that exact moment in the depths that make up the vessel, tiny army of engineers (and a lot of computer systems) are working hard to ensure that the light is on, air conditioner cools, toilets running and the propellers spinning.
The character from John Irving’s “The World According to Garp” was of the opinion the feeling that “had grown up on a large ship without having seen, much less understood, the engine room.” If you’re not among the handful of people who eagerly (and often fail) attempt to take the chance to tour an engine room during every cruise, we do not pay much attention to what happens beneath the passenger decks. However, events that are widely reported such as those of Carnival Triumph engine room fire in 2013 have created fear and curiosity about the way these ships operate.
To calm your anxieties and satisfy your need to know more, we’ve begun to shed clarity on the often elusive topic of cruise ship operations No engineering degree needed.
Engine Room
The most essential thing to know regarding the room’s engine area is where it is located. Because ships require their most hefty weights to be placed as low as is possible to maintain security, the engines typically located on top of the keel. The decks below the vessel are largely used for machinery.
As one would expect, an area which can generate enough power to propel an enormous vessel through the waters is massive engines typically are more than three levels tall. Because space is the limit on cruise vessels the engine rooms may not be the huge and cavernous area you think of. Instead of a vast continuous hall running across the entire length of the hull the machinery is separated into smaller compartments that are watertight. One of the compartments could contain the main engines, while another compartment could be used to house the air conditioning system.
Compartmentalization is a method of ensuring security reasons. If there is a the possibility of a fire or an attack on the hull, several compartments are used to limit the damages.
In extremely rare circumstances engines can be located elsewhere than at the lowest point of the vessel; in Cunard’s Queen Mary 2 the four diesel engines are located over the keel. The two smaller gas turbines, which are lighter, are located on the high point of the ship, just aft from the funnel.
An interesting aside In the past it was common for older lines to have two engines rooms. The advancement of technology allowed engines to be condensed. However, current legislation calls for ships to have duplication of equipment as well as two engine rooms.
Getting the Terminology Straight
Before we proceed in this article, let’s settle on a few basic terms since the technical language can be confusing. To be used in this post “main engines” refer to the engines that provide the immense power required to move the vessel. On traditional or direct drive diesel vessels, the engines are linked with the shaft of the propeller. on diesel electric vessels these engines will be linked to the generators that power the ship.
Additionally, “engine” and “motor” are not interchangeable. Motors are powered by ignition and fuel to create electricity. Motors are powered by electricity to help make things move. Propulsion motors utilize the electricity generated by engines and utilize it to cause the propellers to turn.
Conventional Diesel
Despite the slang term about “steaming to St. Thomas,” the steam engines that were once used in ships are almost gone. (The last passenger ship that had a steam engine the Sitmar’s FairSky from 1984 – – – was removed at the end of 2013.) Nowadays diesel engines are now the norm.
How can diesel engines be used? Consider older ships, like the Titanic. Steam pressure in chambers drove pistons upwards and downwards. The pistons were linked to a crankshaft that transformed the vertical movement of the pistons into a rotational motion. The crankshaft was directly linked to the propeller via an extended propeller shaft. The greater the speed at which the pistons on the engine moved upwards and downwards the more quickly the propeller shaft turned , and the faster the ship was.
On a few smaller and midsize vessels, like National Geographic Explorer or Windstar’s Star Breeze, Legend and Pride The concept is not drastically different. The principles are identical; the primary difference is the method by which power is generated. In lieu of using steam to make pistons move up and down the ignition of fuel produces pressure, which pushes the pistons upwards and downwards while turning the crankshaft which is attached to the propeller shaft.
Since engines are typically rotating a crankshaft at fast rate (often many hundreds of thousands rotations per minute) it is linked to propellers via gears. Propellers are engineered to spin at a slower rate typically 250 minutes or less. The gearing permits the engine to spin at a higher, faster and more efficient speed, and permitting propellers to spin slower, but also more efficientspeed.
One benefit that modern “direct drive” diesels have is the possibility of employing a shaft generator which makes use of the circular rotation in the propeller shaft to produce energy for hotel services such as illumination and cook. Of of course, shaft generators are only able to be used in the event that the vessel is at sea at a steady speed. If the propeller shaft doesn’t turn it won’t turn the generator, so it won’t be able to generate electricity.
Although the majority of ships are constructed using conventional diesel plans most newly built cruise ships (such such as the Celebrity’s Edge Class or Carnival Horizon) come with some sort that uses “diesel electric” propulsion. On these vessels, the primary engines aren’t connected to the propeller shafts. instead they are connected to generators that have only one task: generating electricity.
The power they generate is transmitted to electric motors that are then used to power and turn the propellers. In most cases, there are several smaller engines which make up the power requirements for the ship. In port, one engine might be operational, however out in the sea at maximum speed, all of them could all be on.
The most important benefit that diesel systems offer is their efficiency and allow engines to operate at their highest efficiency settings whatever the vessel is traveling at 5 knots or 20 knots.
New Technology for the Environment
But, the latest technology and research is bringing ever higher efficiency and sustainable vessels. More than 20 cruise ships are expected to be operating driven by Liquified Natural Gas, or LNG The first ship, AIDAnova, set sail in December of 2018.
LNG-powered ships are equipped with engines that have been altered to use natural gas which is turned into liquid and then kept at a temperature of 260° below zero in specially-insulated tanks for fuel. Although the infrastructure used in ports to provide LNG is not completely globally, the benefits for cruise ships are numerous and include the reduction in nitrogen oxides of around 80 percent as well as carbon dioxide emission in 20 percent.
Hybrid propulsion engines are becoming more popular. Similar to a hybrid car hybrid ships are powered by two different power systems. Hurtigruten’s Roald Amundsen might be the most famous example. The ship is equipped with numerous battery packs, which will provide enough battery power to run and navigate the ship even when all diesel engine power shutting down.
At present, the batteries provide enough power to provide only 30 minutes of quiet and emission-free navigation until diesel engines need to be replaced and as technology for batteries improves, Hurtigruten expects that time to grow.
The latest developments within the underwater structure can help to make cruise vessels more efficient. Royal Caribbean’s Quantum of the Seas, Norwegian Bliss and Celebrity Edge make use of thousands of air bubbles beneath the hull in order to increase efficiency. The bubbles, which are released under water from the bottom of the vessel, decrease the space of the ship’s hull which comes into contact with sea. This decreases friction which can slow a ship down, and increases the efficiency of its fuel by as much as 10 percent.
It’s All About the Power
A loss of power to ships can be catastrophic. The main engines, and generators require power to continue operating. Electrically powered pumps draw cold seawater from the ocean to cool the engines. Electric pumps draw fuel from tanks that hold fuel and then supply the engine with fuel. Electrical power is essential to many of the operating functions in the absence of it, the vessel stops.
It is true that the creation of electricity is crucial for all aspects of the operation of a vessel. The largest equipment (such as bow thrusters, or for diesel electric vessels the propulsion motor) requires electricity with high voltage. For smaller equipment like lights in your cabin , or the galley equipment the power goes through a transformer before being decreased to a suitable voltage that is lower in voltagefor example, 110V.
To distribute electricity the cables are long and slender throughout the vessel. The cables, which span hundreds of miles transport power from generators to switchboards, and then through cabins, passageways and public areas.
The cables can be one of the weak points in the distribution system of a ship. Even ships that have two engine rooms could suffer power outages in the event that the electrical cables aren’t completely redundant. In the case of two major engines in two different engine rooms generate electricity that is then transferred to one cable that supplies power to the propulsion motors an issue with that electrical cable could shut the power for propulsion completely.
Imagine it as a highway. If an accident blocks the road, the traffic (i.e. electricity, for instance) isn’t able to move until there’s a detour or alternative route that provides a alternative to the issue.
Portside Power
If ships are docked and not moving, the main engines and generators generate more power than is needed. When they’re in port, they’re shut off, while smaller generators are utilized to power to the “hotel” load (i.e. lights, air conditioning, lights and galleys, etc.). Moving the ship across the water consumes the majority of the ship’s requirement for power. Approximately between 85 and 85 percent power that a diesel electric power plant generates goes towards the propeller. The remainder is used to keep the lights on and keeping the passengers and crew comfy.
This is why hotel facilities can be restored even when the propulsion of the ship isn’t functioning Separate generators supply power , but they don’t go towards moving the vessel. (However in the event that there’s a fire that destroys the wires that supply the power the generator, having a separate one isn’t going to make any difference.)
In the present increasingly, ports (and ships) are fitted with systems that permit the ship to “plug in” to a local shoreside electric grid once docked. The engine of the ship can be switched off, which helps to reduce emissions and pollution.
Emergency Generators
What happens if something goes wrong and the ship is stranded in the sea? Every ship has an emergency generator in order to supply vital electric power.
The backup generators are placed higher up and out of the rooms in the engine room to shield them from damage or fire in the engine area. Large ships require such power that they may be equipped with at least two emergency generators. However, they’ll not have the power of the main generators and engines. They’re not able to generate enough power to propel the ship and they’re not able to supply all the power that is needed for port operations, mostly due to space limitations.
So an emergency generator utilized for only the most essential navigation systems — vital communications and bridge equipment a couple of important pumps located inside the engine room (such as those that provide fuel to the engine) as well as emergency lighting. (Cruise emergency lighting for ships generally is pretty good. It is easy to tell the lights that are operating in the emergency switchboard by there’s a small red dot on the light. If you are on your next cruise, look while you stroll through the aisles and search to see the red dotYou might be amazed at how many lights are on during an emergency.)
In the event that the emergency generator should fail ships must be equipped with -and we’re not making it up the idea of a battery backup. Battery rooms offer at minimum 24 hours of power and a much smaller array of backup equipment. However, the basic equipment they provide is too limited to provide power to many hotel services and certainly aren’t enough to power the ship.
Safe Return to Port
What is doing to be done so that that incidents similar to that of 2013’s Carnival Triumph Stranding won’t occur again? Plenty, actually.
In the past there were no emergency power sources and they were not strong enough to handle “nonessential” items, like air cooling which is among the largest power drawers of hotel loads. (That is not likely to be the case in the near future. It can feel uncomfortable and hot on a vessel however, it’s not a risk.)
Also, the vacuum pumps that were required for the toilets were considered “emergency equipment.” In reality, International Maritime Organization regulations called “Safe Return to Port” were in effect for all passenger ships greater that 120 meters (393 feet) constructed after the year 2010. In recognition that the increase in passenger capacity means it is more difficult to remove large vessels and therefore, these rules are created to ensure that, in the event of an incident like a fire there are enough redundant facilities to ensure that passengers are in a safe environment for longer and enjoy basic services.
The regulations call for complete redundancies, which includes two engine rooms as well as the double-up of electrical cables and systems that run across vessels. So, in the event that a fire damages one engine room as well as the generators that supply energy to propel the vessel, another engine room with sufficient power to move the ship remain operational.
Although the ship wouldn’t be able to move at normal speeds but it could be able to navigate with the aid of tugboats. The most groundbreaking is the guidelines for basic services, including the specifications for a toilet that is functional for every 50 individuals.
Following Carnival Triumph’s fire, Carnival Triumph incident, Carnival Cruise Line made announcements that went beyond that of “Safe Return to Port” guidelines. Each of its ships took part in a $300 million fleet-wide retrofit, and also received an emergency generator that powers 100 % of the staterooms and public toilets, as well as fresh water and elevators.
In a subsequent stage, Carnival installed a second permanent power backup system on every ship to ensure that hotel services are more extensive in the event of power loss, such as additional cooking facilities including cold food storage, even phone and internet connectivity.
While no regulation is able to address all possibilities however, these modifications will help in making sure that power losses are more likely… as well we will be able to spend more time relaxing at sea without worrying about what cruise ships do.
