How Cruise Ships Really Get Into The Water

You’d think getting a cruise ship into the water would be simple. Build it, float it, done. But for some ships, the launch is one of the most dangerous and carefully planned moments of the entire build.

These floating cities can weigh more than 200,000 tonnes, yet shipyards somehow move them into the sea with incredible precision. Sometimes they slide sideways. Sometimes entire docks are flooded beneath them. And one wrong move could cost millions.

The way modern cruise ships get into the water is far more fascinating than most people realise… and one method completely changed the industry

The Different Ways Ships Can Be Launched

There are four main ways that ships can be launched into the water. Two of those only really apply to smaller ships, though.

1. Mechanical Launching

Mechanical launching involves using a crane to lift a boat or small ship, and then moving it into the water. Imagine trying to do this with a cruise ship!

2. Air Bag Launches

Some boats and small ships are launched by placing air bags underneath, inflating them, and then using that cushion of air to slide the ship into the water.

The two methods above aren’t possible with most cruise ships. There’s not a crane in the world that could lift a completed cruise ship, nor can airbags lift that much weight.

3. Gravitational Launching

Gravitational launching is a method used for cruise ship-sized vessels, but not really with actual cruise ships these days.

This method involves transporting the ship to the side of the water, if that wasn’t where it was built, and then using sliders to slide the ship into the water at the side.

The momentum causes the entire ship to plunge into the water, before it rights itself just in time to avoid taking on water from the top deck.

It’s messy and dramatic, and it risks damage to the ship because of the pressure placed on it by the sudden force of water.

It looks cool on YouTube videos, though.

4. Floating Out

The fourth method is far less dramatic, but it’s by far the safest and smartest option for modern cruise ships.

How Floating Out Works

Cruise ships are launched into the water using the float-out technique. This means the cruise ship is built in a special dry dock – an open dock area which has been drained. Once the ship is ready, the dock is flooded with seawater and the ship simply floats out.

While the actual launching of the ship is therefore low on drama, it’s often accompanied by a lot of pomp – cruise ships are expensive and so cruise lines like to celebrate each stage of their building journey.

Here’s an example from when Disney Wish was floated out – it’s Disney, so of course there are multiple sets of fireworks:

I also recently attended the floating out of the brand new Disney Destiny, which was super fun to be part of.

In terms of the safety of the ship, floating a ship out really is the best way. The ship is just positioned on a dry space, and then, once that dock is flooded, it naturally begins to float. There’s no risk of waves crashing against it or shock forces. The supports holding the cruise ship upright don’t move, and the ship just naturally rises from them.

Obviously, for this type of launch to work, you need a lot of space, and so dry docks are limited to just a handful of shipyard locations around the world.

Here’s a look at the biggest ship in the world, Icon of the Seas, floating out for the first time. It involved 219 million litres of water, which took 9 hours to fill the dock.

Cruise Ship Float Outs, Step-by-Step

Here’s a quick run-down of how cruise ship float outs work.

Cruise ships are built in a large dry dock, using support structures to make sure they stay upright. It’s always interesting to see photos of a cruise ship out of water – it doesn’t look right.
Once the outer shell is completed and the ship is judged to be sea-ready, the float out begins.
The dock is flooded using seawater. This is a slow process that is often done overnight.
Once the dock is flooded, the ship will begin to float.
The ship is then dragged into position, often out of the hangar where it was built, using tugboats. The ship’s engines are not usually used at this stage.
Once the ship is in the new, correct position for construction to continue, it is anchored and secured in place.

Construction will then carry on until the ship is almost ready for passengers. She’ll then be sent on sea trials while final fixtures are added.

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That’s the practical side of a float out, but there may be other ceremonial steps involved too. Again, this is seen as quite an important stage in a cruise ship’s life.

So often, speeches will be given by the CEO of the cruise line or another senior staff member. The ship’s godmother may also be present, and a bottle of Champagne may be smashed against the hull. This will be repeated at the naming ceremony too.

Depending on the ship and the stage of the build, the senior dignitaries may take in the float out from the dock at the side of the ship, or they may board and witness it from the current top deck.

Cruise Ships Are Often Finished Off in the Water

The initial steps of a cruise ship’s build don’t happen in the water. They happen in a dry dock, which has been drained. Once the exterior of the ship is complete and the ship can be floated, the dock will be flooded, the ship floated out, and construction will continue.

So, ships are partially built while they’re in the water. It may be that the ship needs to be moved to a new location to fit specialist features, or it just has to be outdoors to allow for larger works to be carried out on the ship.

This means that ships are typically floated out as soon as they’re ready. The dry docks will have limited space for just the shell of the ship, and when that is intact and seaworthy, the ship is floated into a bigger area to make it easier to fit the ship with the next building blocks.

Once a ship has been floated out, it will stay in the water almost permanently. The only difference is when she may need to undergo extensive repairs or renovations, such as Royal Caribbean’s Amplification Program.

When this happens, she’ll return to the shipyard for another dry dock. She’ll be positioned above support structures, and the water will be slowly drained until the ship is sitting on dry land.

The repair work will be carried out, and then the dock will be flooded again, ready for the ship to float out and resume service.

Final Word

Launching a cruise ship might not look as dramatic as those old sideways launches you see online, but the modern float-out process is an incredible piece of engineering.

Instead of crashing into the water at high speed, these giant ships are carefully lifted by millions of litres of seawater until they naturally begin to float. It’s slower, safer, and far better for protecting ships that can cost well over a billion dollars to build.

And while the process itself is surprisingly calm, seeing a cruise ship float for the very first time is still a pretty amazing moment. It’s hard to believe something that enormous can simply rise out of the dock and sail away.