Technical Question About The Engines

Chief Engineer Frank de Vries

Howard Bardsley III sent us an e-mail asking why Eurodam has four 12-cylinder and two 8-cylinder engines. Blog Board member and Chief Engineer Frank de Vries gave us such an interesting answer, we thought we’d share it with Howard and everybody else:

The reason that we have four 12-cylinder engines and two 8-cylinder engines is that this configuration gives us more flexibility in regards to the amount of power that we want to generate. Depending on the speed of the ship we need more or less power.

A diesel engine has the optimum efficiency when it runs around 85 percent load. Therefore, we always try to run the engines at that particular load while we are underway.

Having 12- and 8-cylinder engines gives us the possibility to make different combinations, e.g., (2 x 12 + 1 x 8), or (3 x 12 + 1 x 8), or (2 x 12 + 2 x 8), etc. This way, we can always run our engines at 85 percent load and the steps to increase or decrease are not as big as if we only had 12-cylinder engines.

The power output of the engines is 1,000 kilowatt per cylinder, so the total would be 64,000 kilowatts, or 64 megawatts, which equals approximately 85,000 horsepower. That is the maximum load, however, we normally run at 85 percent of that.

The Azipods have a power of 17.6 megawatts each, so a total of 35.2 megawatts, which equals almost 47,000 horsepower.

Captain’s Log: Navigating with GPS

Eurodam’s bridge looks a lot closer to ready than it did the first time we saw it.

Today Captain Jeroen van Donselaar explains some of the finer points of nautical navigation:

GPS is short for “global positioning system.” It is a satellite-based navigation system that was commercially introduced in the early 1990s. It is based on the principle of measuring time differences between signals sent from three or more satellites that are “visible” at the location of the receiver. This receiver can be a built-in navigation system in a car, a ship or an airplane. These days there are even hand-held receivers.

Before GPS, other, much less accurate navigation systems were used such as NNSS (Navy Navigation Satellite System, the forerunner of GPS, only gave a “fix” every 90 minutes), Loran C, Omega, Decca and Consol. Other means of “position finding” are RDF (radio direction finding), visual/radar bearings in combination with radar distances.

The major difference between the older systems and GPS is that GPS provides a continuous and very accurate real-time position versus a somewhat accurate position every now and again. GPS works regardless of weather conditions, visibility and at any latitude, and is extremely reliable. I say latitude because most of the other systems were not available in the very northern or southern regions of the globe.

GPS has taken the guesswork out of navigation, so to speak. This is somewhat unappreciated sometimes by our younger deck officers who always have had the luxury of never having any doubt about the ship’s location. Myself and the chief officer are probably the only ones on board who started our careers before the advent of GPS, so we certainly appreciate the difference it has made!

In the early days GPS was just a box that would display latitude and longitude and course and speed over the ground. We would have to take this information and plot it on a paper chart in the same way we did with the other systems, only with much greater accuracy. During the first Gulf War the accuracy of GPS was further increased when the deliberate inaccuracy effect called “dithering” was turned off, supposedly for the benefit of guided missiles. These days I would say GPS is accurate to within 10 feet.

Nowadays our GPS receivers are more advanced and are at the heart of our integrated bridge systems. Although we still use paper charts as a backup, our primary navigation is now done via ECDIS, which means Electronic Chart Display Information System. The STN Atlas integrated bridge system on the Vista- and Signature-class ships takes it a step further and also superimposes a radar image including the AIS, or Automatic Identification System labels of other ships on the same screen.

In my office on the ship, which is located between the bridge and my quarters, I have a large flat-screen monitor that is basically a repeater of the main navigation display on the bridge. In this way while I am working at my desk I can keep an eye on things.

How do You Steer the Ship?

Eurodam’s wheel already is in place on the bridge

When you picture the ship’s wheel, do you imagine something along the lines of a giant wheel with spokes adorning its circumference to enable steering? Well, times have certainly changed, and though ships keep getting bigger and bigger, ship wheels of today are surprisingly small for the job they have to do. Yet despite their size, they still have the power to steer today’s megaships. To find out exactly how a ship is steered, we asked Eurodam’s Captain Jeroen van Donselaar for an explanation.

It is a common misconception that the captain steers the ship himself or is always on the bridge when the ship is at sea. The presence of the captain on the bridge is required when entering or leaving port, during reduced visibility, in heavy weather or dense traffic, and when circumstances so dictate.

The captain or the second in command — the chief officer — always maneuvers the ship alongside or off the berth, but this does not mean we are actually steering or are “at the helm” as we prefer to call it. This job is done by helmsmen who have the rank of quartermaster, which at Holland America Line is a position in between able-bodied sailor and boatswain. In pairs of two, these gentlemen assist the watch officer on the bridge on a four-hours-on, eight-off rotation. They are not licensed, but are qualified to act as helmsman and lookout, and to provide general assistance to the watch officer.

When at the helm, they take orders from me, the chief officer, the watch officer or a pilot, depending on who has what we call “the conn,” which means who is handling the ship at the time.

The orders given to the helmsmen can be course orders, such as “Steer zero nine zero,” direct rudder orders such as “Starboard ten,” or rates of turn such as “Fifteen degrees rate of turn to port.”

The actual helm is quite small, not bigger than the steering wheel of a car. Generally, the quartermasters are only at the helm when the ship is sailing in confined waters such as buoyed channels or rivers, or when making large course alterations. At other times the ship is steered electronically through various autopilot systems.

The main autopilot system is called NACOS, for Navigation Command System. Quite literally the ship can follow a preprogrammed track by itself and can even slow down at its destination. It will not allow for traffic though. These preprogrammed tracks end near the entrance of a port and from there on it’s all manual again until the ship is docked.

P.S. Thanks to Blog Board member Andre van Schoonhoven who got us the photo of the ship’s wheel in record time!

Insulating for Safety

Chief Officer and Blog Board member Andre van Schoonhoven sent us these behind-the-scenes shots of fire-proof insulation being installed on Eurodam.

Recently, the U.S. Coast Guard went on board to conduct the structural fire protection inspection. According to Andre, insulation is a very big part of that inspection. Because of the insulation material, the bulkheads will contain fires for up to 60 minutes.

Andre said that so far a total of 140,000 square meters (1.5 million square feet) of insulation material has been installed on the ship.

Views from Under the Waterline

Here are a couple more photos from Eurodam’s recent drydock in Trieste, Italy.

Chief Electrician Ed van Weijen sent this image of the two Azipod propulsion units. You can really grasp the size of the ship when you compare it to the size of the workers. Note the one worker on the scafolding by the portside Azipod and the two workers near the center of the photo touching up the ship’s paint.

Captain Werner Timmers, master of Zuiderdam, was kind enough to send us an “Azipod 101″ that explains how the podded propulsion units work:

Basically the pods are big outboard engines. The propellors and their electric motors hang underneath the ship and can be rotated to provide thrust in any direction we want. So to steer, we turn the pods. There are no rudders. For maneuvering in port we also have three bow thrusters with 2,500 horse power each.

There are basically three modes to steer the ship:

When in sea mode, either the ship’s wheel or the autopilot on the bridge controls both pods at the same time, and the steering angle is limited to 35 degrees. This is much like a conventional ship. The wheel is only about one foot across — not like in the old sailing ship days.

When in maneuvering mode, the control of the pods is separated and they are operated individually from two separate control levers. Each pod can be turned 360 degrees and run forward or astern as needed.

When in joystick mode, both pods and the thrusters are controlled by a single control lever. We turn the control lever in the direction we want the ship to move and the computer decides how it will use the pods and thrusters to accomplish the movement.

Chief Officer Andre van Schoonhoven sent us the photo of the port stabilizer fin below. Stabilizers usually are used to reduce the roll that a vessel experiences while underway due to wave action. The fins extend beyond the hull of the vessel below the waterline, and their angle can be adjusted depending on the heel angle of the vessel. The stabilizers operate similarly to airplane wings.

Satellites Antennas Installed

Don’t worry, Eurodam cruisers! You’ll be able to access your e-mail and catch up on worldly events on CNN during your cruise. Blog Board member Ed van Weijen sent us these images of one of the television satellite antennas being installed and all three antenna domes in place.

According to van Weijen, the two outer domes are for the television system, and the dome in the middle is for the communication systems.

There also are two smaller antenna domes behind the three large ones — one is the back-up for the communication systems and the other one also is for communication, but it’s more expensive to use.

What is a Bow Thruster?

Chief Officer Andre van Schoonhoven and First Engineer Marcel Kiers inspecting bow thruster #2 during the dry dock in Trieste.

We received this cool image of Eurodam’s bow thrusters taken during the ship’s recent dry dock, and we thought it would be interesting to post it with information on the function of the bow thrusters. So, we went to Captain Jeroen van Donselaar to find out the answer:

A bow thruster is a device that is fitted in the bow, as much forward as technically possible, to enhance maneuverability of the ship. Bow thrusters are only useful at slow speeds or when the ship is stopped, which is when the bow thruster is most efficient.

Unless in clear water or in drydock, the bow thrusters are normally not seen.

Most designs have a reversible propeller, driven by an electric motor, that sits in a tunnel which is part of the hull. Because the propeller is reversible, bow thrusters can be used to push the ship’s bow to port (left) or to starboard (right). When the bow thrusters are operated together with the pods, which are located at the stern of the ship, the ship can move sideways or turn on a dime.

Because of their large ’sail’ and subsequent need for ‘force,’ our Vista and Signature class ships are fitted with three bow thrusters.

Anchors Aweigh

Eurodam’s anchor is in place. First it was put on a barge and floated up alongside the ship. Then it was connected to the anchor chain while still laying on the barge before being hoisted up into position.

Check out our previous post on the anchor so you can see how big it really is.

Testing the Mooring Winches

Chief Officer Andre van Schoonhoven sent us the latest photos from the yard. They’ve just completed testing of the mooring winches — the machines that pull the ship to the dock and hold it in place. Here’s how Andre described it:

The mooring winches were tested for their rated power. Rated power is 52 tons of bollard pull, and we got them up to 57 tons on the strain gauge. (Note: a bollard is the strong post on a pier that the mooring line is attached to.) That means they can pull an object of 125,400 lbs!

The test also provided the opportunity for Rolls-Royce, manufacturer of the winches, to adjust all the settings on the electro motors and their control stands.

The winches are equipped with so-called self-tensioning modes, which means that if the strain on a mooring line gets above a certain setting, the winch will pay out the line, rather than breaking it, and when the strain gets lower, it will automatically heave in again.

The testing is performed by putting a steel cable on the winch drum, and putting the other end around the bollards on deck, with the measuring device in between.

That way, the bollards get tested at the same time.

UPDATE: In response to a question from a reader, Andre gave us the lengths of the anchor chains and mooring lines:

The mooring lines are 220 meters long, tip to winch line, manufactured by Lankhorst Sneek. The anchor chains are 364 meters long.

An Artsy View of Eurodam’s Engines

Chief Electrician Ed van Weijen sent us these updated images of Eurodam’s engine room and engine control room. Who knew he had an artistic side as well?

The ship will derive its power from four 12-cylinder V-type and two eight-cylinder (above) in-line engines.

The engine control room, at the heart of the ship, looks like it’s nearly complete.