Most cruise ships draw between 25 and 32 feet of water

A draft — the depth a ship sinks into the water — depends on the ship's weight and the shape of its hull. Large modern cruise ships typically sit 25 to 32 feet below the waterline. A few of the largest ships, like Royal Caribbean's Wonder of the Seas, draw closer to 32 feet. Smaller ships used for river cruises or expedition voyages draw much less, sometimes only 15 to 20 feet.

The draft matters because it determines which ports a ship can enter. A port with a channel dredged to 30 feet cannot accept a ship that draws 32 feet. This is why cruise lines sometimes avoid certain destinations or must time their arrival for high tide. It also affects how much cargo and fuel a ship can carry — a heavier ship sinks deeper.

Draft changes throughout a voyage. A ship leaving port fully loaded with fuel, water, and supplies sits deeper than the same ship arriving at the next port after passengers have consumed those resources. A ship also sits lower in freshwater than in saltwater, because freshwater is less dense and provides less buoyancy.

Key Takeaways

  • Most large cruise ships draw between 25 and 32 feet of water, meaning they sit that deep below the surface.
  • Shallower draft allows ships to visit more ports, while deeper draft limits options but allows larger vessels.
  • A ship's draft changes based on how much fuel, water, and cargo it carries, and whether it is in saltwater or freshwater.
  • Port channels are dredged to specific depths, so a ship that draws too much water cannot enter without waiting for high tide or using a pilot to navigate carefully.

Why draft matters for cruise itineraries

Cruise lines plan routes around the ports their ships can physically reach. A ship that draws 32 feet cannot enter ports with channels dredged only to 28 feet. This is why newer, larger ships sometimes skip smaller or historic ports that older, shallower-draft ships can visit.

Some cruise lines have built smaller ships specifically to access shallow-water destinations. Windstar Cruises and Seabourn operate ships that draw 20 feet or less, allowing them to dock in places like the Greek islands, the Caribbean, and Southeast Asia where larger ships cannot go. These ships carry fewer passengers but reach ports that bigger cruise lines cannot serve.

High tide can temporarily increase the water depth in a channel, allowing a deeper-draft ship to enter. Cruise lines sometimes schedule port calls to coincide with high tide windows. A pilot — a local informed who boards the ship — may also guide a captain through a shallow channel by finding the deepest path through it.

How ship weight affects how deep it sits

A heavier ship sinks deeper into the water. A cruise ship's weight comes from its structure, engines, fuel tanks, freshwater tanks, ballast water, cargo, and passengers. When a ship is fully loaded at the start of a voyage, it sits at or near its maximum draft. As passengers consume food and fuel, and as the ship burns fuel to move, the ship becomes lighter and sits higher in the water.

Ship captains and engineers manage ballast water — seawater pumped into tanks below the waterline — to adjust the ship's draft and keep it level. If a ship is too light, it may sit too high and become unstable in rough seas. If it is too heavy, it may not have enough freeboard (the distance from the waterline to the top of the ship) and could take on water in waves. Ballast is pumped in or out to maintain the right balance.

The difference between saltwater and freshwater draft

Saltwater is denser than freshwater, so it provides more buoyancy. A ship floats higher in saltwater than in freshwater at the same weight. This means a ship that draws 28 feet in the ocean may draw 29 feet in a river or lake. The difference is usually 1 to 2 feet depending on the ship's size and the salinity of the water.

River cruises and inland waterway cruises must account for this. A ship designed for river cruises is built with a shallower draft specifically because rivers are freshwater and because river channels are often narrower and shallower than ocean ports. The Danube, Rhine, and Mississippi rivers all have depth limits that determine which ships can navigate them.

How to find a specific ship's draft

The draft of a specific cruise ship is listed in its technical specifications, usually available on the cruise line's website or in ship databases. Search for the ship's name plus "draft" or "specifications." You will find the maximum draft — the deepest the ship sits when fully loaded.

If you are planning a cruise and want to know whether a ship can visit a particular port, check the port's channel depth and compare it to the ship's draft. Most cruise line websites list the ports on each itinerary, and you can research each port's depth restrictions separately. Some ports publish tide tables that show when the deepest water is available.

Why newer ships sometimes draw more water

Larger, newer cruise ships often draw more water than older ships because they are heavier and wider. Modern ships are built to carry more passengers and amenities in the same footprint, which adds weight. A ship that is 180,000 tons will draw more water than a ship that is 90,000 tons.

This creates a trade-off for cruise lines. A larger ship carries more passengers and generates more revenue per voyage, but it can visit fewer ports. A smaller ship visits more ports but carries fewer passengers. Cruise lines choose their ship size based on the itineraries they want to offer and the ports they want to serve.

What happens if a ship tries to enter a port it is too deep for

If a ship's draft exceeds the available water depth, the ship runs aground — its hull touches the bottom. This can damage the hull, injure passengers, and strand the ship until high tide or dredging allows it to float free. Cruise lines and port authorities carefully monitor draft and channel depth to prevent this.

In rare cases, a ship may be stuck for hours or days waiting for high tide. In 2016, the cruise ship Carnival Legend ran aground in Alaska because the captain misjudged the depth. The ship was refloated at high tide with no serious damage, but the incident delayed the voyage and cost the cruise line money.

Frequently Asked Questions

Can a cruise ship enter a port if the water is too shallow?

Not safely. If a ship's draft exceeds the channel depth, the ship will run aground. Cruise lines avoid this by checking channel depths before scheduling port calls and by timing arrivals for high tide when possible. A pilot may also guide the ship through shallow channels by finding the deepest route.

Do all cruise ships draw the same depth of water?

No. Large ocean-going cruise ships draw 25 to 32 feet. Smaller ships designed for rivers or expedition cruises draw 15 to 20 feet or less. The draft depends on the ship's size, weight, and hull design. A ship's draft also changes based on how much fuel and cargo it carries.

Why do some cruise lines use smaller ships?

Smaller ships draw less water and can visit ports that larger ships cannot reach. Windstar and Seabourn operate small ships specifically to access shallow-water destinations like Greek islands and Caribbean coves. These ships carry fewer passengers but offer access to places that big cruise ships cannot go.

Does a ship sit deeper in winter or summer?

A ship's draft depends on its weight and the water density, not the season. However, rivers and some coastal areas have seasonal water level changes. A river may be shallower in summer due to lower rainfall and higher in spring due to snowmelt, which affects which ships can navigate it.

How do ship captains know if they can enter a port?

Captains check the port's published channel depth and compare it to the ship's maximum draft. They also consult tide tables and may contact the port authority for current depth information. A pilot who specializes in that port may board the ship to guide it through shallow or narrow channels.