Beneath the Surface: Exploring the Cruise Ship Hull

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When booking a cruise vacation, you are probably far more concerned with the onboard amenities, dining options, cabin accommodations, and what shore excursion you want to do than you are with the actual structure of the ship.

Even though it may seem less glamorous than other aspects of your vacation, it is worth considering the ship itself. A greater understanding of the ship and how it works will help you appreciate how incredible a modern cruise ship is. 

Today, we will take an in-depth look at what lies beneath the surface of a cruise ship by exploring the hull. Not only will we explain what is down there, but we will also explain the critical function the hull serves. We will even address some common questions cruise ship passengers have about the hull.

If you want to expand your understanding of cruise ships and their operation, you have come to the right place!

What Is a Cruise Ship Hull?

The hull of a cruise ship can be seen as the base and outer shell of the entire vessel. Essentially, it is the portion of the ship most submerged in the water. For this reason, the hull plays a critical role in keeping any cruise ship afloat. 

The hull sits below the waterline, covering a cruise ship’s entire underbody. This means it extends from the bow of the ship right to the stern. In terms of its height, it also runs from the waterline down to the ship’s keep, which is the lowest point of any ship. 

Since the hull must withstand harsh conditions, like crashing waves, significant water pressure, saltwater, and even impacts, it needs to be incredibly strong. Just how big a ship’s hull is and how much of it remains underwater depends on the specific size and type of cruise ship you are discussing; however, it tends to be a significant portion of the ship’s entire structure and mass. 

What Are the Basic Functions of a Cruise Ship Hull?

The hull of a cruise ship is incredibly important. It provides a physical structure for the ship to be built upon and the buoyancy required to keep the cruise ship and everything it is carrying afloat. The hull also helps reduce water resistance, which helps with everything from improving fuel efficiency to allowing the ship to travel through the water smoother and faster. 

Bulbous bow, hull and waterline
Bulbous bow, hull and waterline (Photo Credit: canduca)

In this sense, the hull provides the stability required to allow such a massive vessel to float on the water. The hull also needs to safeguard the ship and prevent it from sinking. As we will discuss in greater detail, within the hull itself, you will also find various compartments that can contain essential equipment needed to keep the ship functioning efficiently and safely. 

Even though you may not see much of the hull as a passenger, it plays a massive role in allowing you to enjoy any cruise vacation. 

What Are the Different Areas of a Cruise Ship Hull?

Like just about any type of large vessel, a cruise ship hull will feature numerous different compartments and spaces. As you will learn, each plays an essential role in allowing the ship to function safely. 

The Engine Room

As the name implies, the engine room contains the ship’s engines and propulsion system. It can be seen as the ship’s heartbeat, so it serves an important role. Since the ship’s propulsion system needs to sit below the waterline, it is only natural that the engine room sits within the ship’s hull.

Cruise Ship Engine Room
Photo Credit: Turn_Mug / Shutterstock

A significant amount of the ship’s fuel will also be stored in the hull. Typically, the fuel is stored near the propulsion system, but it can be located in other segments of the ship to help maintain its overall balance and stability. 

Ballast Tanks

A cruise ship hull will also contain ballast tanks, which help control the stability of the entire vessel. These massive tanks can be filled or emptied with seawater, which makes it possible to modify the ship’s center of gravity. Ballast tank adjustments are necessary to keep a cruise ship afloat and stable, so they are essential. 

Wastewater Tanks and Waste Treatment Facilities

Modern cruise ships also feature enormous tanks that help store and treat waste and wastewater. While ships in the past may have dumped much of this waste overboard, modern standards help eliminate the environmental impact cruise ships have on the waters they travel through.

Garbage Disposal Area on Cruise Ship
Garbage Disposal Area on Cruise Ship (Photo Credit: Mohd Syis Zulkipli / Shutterstock)

While these tanks and treatment systems are incredibly sophisticated and far more sanitary than you may assume, they still sit out of view of passengers. This explains why they are almost always located in the ship’s hull. 

Storage Compartments

Since there is so much space available in the hull of a cruise ship, it is a good location for various storage compartments and refrigeration rooms. Depending on the ship’s needs, these storage areas can be used to store everything from food and beverages to medical supplies and bedding. 

Crew Accommodations and Facilities

While each cruise ship varies, some cruise ships will feature crew quarters in the upper portion of the hull. Crew members can enjoy breaks and catch up on sleep in these areas. Some ships will also feature separate mess and canteens for crew members in the lower regions of the ship. There are also venues such as a crew bar, gym, and barber.

Crew Quarters on a Cruise Ship
Photo Copyright: Cruise Hive

Can Passengers Explore the Hull?

While the hull is undoubtedly an interesting and important section of the ship, most cruise ships ensure that this area is entirely off-limits to passengers and other unauthorized personnel. 

This is because the hull can be hazardous for those needing the proper training and expertise. For starters, various pieces of equipment and machinery could pose a severe safety risk. Not only is it essential to restrict access to the hull for the safety of the passengers themselves, but it is also essential to keep this area reserved for authorized personnel for the overall safety of the ship.

If, for example, passengers wandered into the engine room unsupervised, the results could be catastrophic. Numerous machines and pieces of equipment are essential to the entire ship’s safe operation down in the hull, so it needs to be protected. 

The Structure of a Cruise Ship Hull

Now that you have an understanding of the inner makeup of the hull, we can take a look at the exterior layers and structure. While it may look seamless from the outside of the ship, the hull of a cruise ship is made up of several segments that all serve a unique function.

The hull’s outer plating composes the most visible layer of the hull. This plating can be seen as the outer skin of the hull. It protects the lower portions of the ship and provides the primary defense against external elements, like water pressure and floating objects. In most cases, this plating is made from hardened steel and coated with specialized paint that can withstand the corrosive effects of ongoing saltwater exposure.

Hull of a Cruise Ship
Hull of a Cruise Ship (Photo Credit: Per-Boge)

Beneath the hull’s outer plating, you will find steel framing and bulkheads. This is what gives the hull its shape and strength. You can think of the framing as the skeleton of the hull. While the plating needs to be incredibly durable, this inner framing gives the entire ship its strength and rigidity. 

Read Also: What’s on the Bottom of a Cruise Ship?

From there, you will find the hull’s inner plating, which, alongside the outer plating, sandwiches the frames and bulkheads. It provides an additional layer of protection and helps enhance the hull’s structural integrity. Given that the entire ship could sink if the hull was not strong, this inner layer serves a vital purpose in maintaining the ship’s safety and stability.


Why doesn’t the hull of a cruise ship rust?

Given that the hull’s outer surface is metal and has to withstand long-term exposure to saltwater, you might wonder why it does not rust. The ship’s outer surface is protected with corrosion-resistant coatings and paints. This acts as a water-tight barrier between the hull’s metal surface and the surrounding water. 

This protective coating must be inspected and maintained at regular intervals to keep the ship safe from corrosion. Scheduled dry docks are used for hull cleaning.

Do cruise ships offer hull tours?

For the most part, cruise ships will not offer tours of the hull. The access to this segment of the ship needs to be carefully regulated to maintain the safety of the individual passengers and the entire ship. In simple terms, allowing passengers to explore the ship’s hull would be too dangerous, even if they were supervised by authorized crew members. 

What is a cruise ship hull made from?

Most modern-day cruise ships feature high-strength steel hulls. This durable material is required to withstand the immense pressure and stress of traveling through oceans and large seas. 

Final Words

If you are a true cruise enthusiast, it pays to have a working understanding of the ship from top to bottom, even if you cannot explore every region. 

Even though the hull of a cruise ship is mainly hidden from view, it serves several essential purposes. If you would like to learn more about the design of a modern cruise ship hull, we encourage you to watch Royal Caribbean’s video guide to the Oasis of the Seas Hull Design.

More importantly, make sure you enjoy yourself on your next cruise vacation, whether you’re heading to New Zealand, New York, or New Orleans, and remember that the ship and the professional cruise line crew work incredibly hard to ensure you are safe and comfortable!

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