How Much of a Cruise Ship Is Actually Underwater?

By Anna Duncan

Cruise ships are some of the most impressive and grandiose vessels ever constructed for human use. They are like floating cities, with multiple decks, hundreds of cabins, and a sprawling array of amenities like spas, pools, restaurants, and more.

But while they may appear to be completely above-water vessels, in reality a significant portion of the ship is actually underwater. Most cruise ships are designed so that around 70% of their total displacement is under water when the ship is at rest. This means that around two-thirds of the ship’s overall weight rests beneath the surface.

The reason why cruise ships have such a large underwater portion is because it helps them to remain stable and seaworthy in rough ocean waters. The deeper a ship’s hull is in the water, the more stable it is against strong currents and waves. Having a large underwater portion also helps to increase the vessel’s buoyancy – which in turn helps it to float better on choppy waters – and reduces drag against wind resistance as well.

The underwater portion of cruise ships typically consists of several key components including fuel tanks, ballast tanks (which help to regulate stability), steering gear, stabilizers (which help keep the ship from rolling back and forth), and propulsion systems. All these elements must be carefully designed so that they can handle immense pressure from deep ocean waters while still providing enough buoyancy to keep the ship afloat at all times.

Cruise ships may look like huge floating structures that are completely above water but in reality much of their design lies beneath the surface. Around 70% of their displacement is submerged in order to help ensure stability even when navigating rough waters, while providing enough buoyancy so that they remain afloat at all times.


In conclusion, cruise ships have a large portion of their structure beneath the surface as this helps them to stay balanced and seaworthy during rough ocean voyages. This submerged section typically consists of fuel tanks, stabilizers, propulsion systems and other essential components which must be carefully designed for maximum efficiency.