What is a Cruise Ship Draft

When it comes to cruise ships, what you don’t see below the waterline is just as important as what’s above it. One of the most critical – and often overlooked – measurements is the draft.

Understanding a ship’s draft can reveal where it can safely sail – and where disaster could strike. But what exactly is it, how is it measured, and why should cruise passengers care?

To get the real story, I spoke to a cruise ship pilot who broke it all down in plain English. Here’s what I discovered.

What Draft Actually Means

The draft measurement for a ship refers to the distance from the waterline to the very bottom of the ship – in other words, a measurement of how much of the ship is underwater at any time. The draft can vary depending on the weight of the ship at the time, due to increased displacement.

As such, if you see any advertised draft figures of a cruise ship (like those I’ve included below), these will be the maximum draft – the largest distance possible for that ship from the waterline to the bottom of the ship when at maximum weight capacity.

Don’t confuse it with a ship draught, which is just where you’ve left your balcony door open!

Ships don’t sit on top of the water. If they did, they would tip over! Instead, they float on the waves with a significant portion of the boat constantly below the waterline – and it’s the depth of this which is measured as the draft.

Read more: How Do Cruise Ships Float And Not Tip Over?

On a cruise ship, the factor which impacts the draft of the ship the most is the fuel weight. Even on the largest ships, the passenger capacity doesn’t have as much of a difference on the draft as the fuel weight.

As a guide, the average American weighs 80kg. So on a cruise ship like the Wonder of the Seas, which might carry 8,000 people, including guests and crew, that’s a weight of 640,000kg or 640 tonnes.

A cruise ship will use between 150 and 250 tonnes of fuel per day and will have a carrying capacity of between 2,500 and 5,000 tonnes of fuel. So, the fuel definitely has more of an impact on the draft of a ship.

The Average Draft of a Cruise Ship

The average draft of a cruise ship is around 21 feet or 6.4 metres. Larger ships do tend to have a bigger draft, but it’s not directly proportional to the length or the gross tonnage – the biggest cruise ships don’t have the largest draft.

I’ve looked at almost 400 cruise ships sailing the ocean, so this average cruise ship draft depth is pretty solid – in fact, around 55% had a larger draft than 21 feet, and 45% had a smaller draft, so it’s close to the median value as well.

It’s a little skewed because some of the smallest ships have a tiny draft, including the National Geographic Sea Bird, which has the smallest draft of all cruise ships – just 1 foot, or 0.3 metres.

This, of course, makes it an excellent choice for exploring parts of the world where the water isn’t very deep.

The Deepest Cruise Ship Draft

The deepest cruise ship draft is 32.81 feet, or 10 metres, and it belongs to the Queen Mary 2 – one of the classic ocean liners of the Cunard fleet of ships. The Oasis-class ships for Royal Caribbean also have a large draft measuring 30.58 feet or 9.3 metres.

Again, though, it isn’t just the largest ships that have the biggest drafts. Indeed, some smaller Royal Caribbean ships (Voyager of the Seas, Navigator of the Seas) have bigger drafts than some of their more recent and larger sisters, such as Freedom of the Seas or Anthem of the Seas. The Icon of the Seas draft hasn’t been announced, but it’s likely to be pretty big – as soon as it’s confirmed, I’ll add it to this guide.

How Draft Is Measured

Draft is typically measured in feet and is tracked using markers on the ship. You can see them a little above the waterline normally – they’re a series of small lines that will be repeated at the bow, the middle of the ship and the aft.

They’re also repeated on both the port and starboard sides, so whenever you get off the ship, you should be able to see the markers – just look towards the waterline.

Depending on the stage of your cruise, you might notice a couple of different colours towards the waterline. Typically, the part of the ship below the water is painted a different colour to the rest of the ship, but there’s usually a mark left by the water, too, especially on older ships.

So when you’re in the latter stages of your cruise and fuel is running less, and people have left the ship for a port day, you might spot the typical draft on the ship from the dock, in the form of a mark left by the water when she is cruising with her normal weight.

Why Draft Matters

All very interesting so far, if you’re really into the measurements of ships at least. But why is the draft important?

You can probably guess – the draft of a ship determines which ports of call it is able to visit. It’s not the only factor – length and width do come into consideration too.

But the draft is the most important. The draft of the ship will prevent it from reaching some ports that stand in shallower water, and that’s when a ship might need to anchor further out to sea and offer tender boats to the port.

How Shallow a Cruise Ship Can Go

A cruise ship can go into any water that is deeper than its maximum draft. So, for the average cruise ship, with a draft of around 21 feet of water, it can go into waters that are 21 feet deep or more. With cruise ships having varying drafts, some ships can go into shallow waters that others can’t.

There isn’t any need for water to be additionally deep – the draught of the ship is the measurement of how deep the ship can go. But the depth of waters around ports is accessible information, and so cruise itineraries are planned with this in mind – ships will only safely sail into ports that are deep enough.

There may be times when a ship has to take a certain route into port – there may be land masses below the water that are inconsistent or rocks, and ships may need to navigate around them.

Reassuringly, every time a cruise ship arrives in port it is joined by a pilot – an expert in the port itself, who will board the cruise ship from their pilot boat and help the crew to navigate the waters safely.

And, of course, the cruise ships have all the best equipment and technology for detecting water depth, too.

Read more: What Is A Ship Pilot And What Do They Do?

Table of Cruise Ship Drafts

Here’s a look at some cruise ship drafts. I’ve included some of the most popular cruise ships in the world, as well as a handful of smaller ships that might be of interest based on their draft size.

I’ve not included every ship in this table – it’d be giant if I did – so I’ve instead picked out examples of ships within different classes for each cruise line, to help demonstrate the example draft and show how larger ships aren’t always those with a larger draft.

Ship name	Cruise line	Size (GT Tonnage)	Draft (Feet)
National Geographic Sea Bird	Lindblad Expeditions	630	1
Celebrity Xploration	Celebrity Cruises (Celebrity Expeditions), Lindblad Expeditions from January 2025	319	4.59
MSC Virtuosa	MSC Cruises	177,100	9.51
Norwegian Encore	NCL	167,800	9.51
Iona	P&O	184,700	9.51
Scenic Eclipse 2	Scenic Ocean Cruises	16,500	9.51
Silver Moon	Silversea Cruises	40,700	9.51
SeaDream I	SeaDream Yacht Club	4,333	13.12
Silver Galapagos	Silversea Cruises	4,077	13.12
Wind Star	Windstar Cruises	5,397	13.48
Braemar	Fred. Olsen	24,344	17.75
Azamara Journey	Azamara Cruises	30,277	19.52
Oceania Regatta	Oceania Cruises	30,277	19.52
Seabourn Odyssey	Seabourn	32,346	19.69
Viking Sky	Viking Ocean Cruises	47,800	20.67
Seabourn Encore	Seabourn	40,350	22.31
Seven Seas Explorer	Regent Seven Seas Cruises	56,000	23.62
Britannia	P&O	143,730	24.61
Carnival Pride	Carnival	85,920	26.25
Celebrity Infinity	Celebrity Cruises	90,940	26.25
MS Eurodam	Holland America Line	86,273	26.25
Oceania Marina	Oceania Cruises	66,084	26.25
Costa Luminosa	Costa Cruises	92,720	26.56
Disney Fantasy	Disney Cruise Line	129,750	27.3
Sky Princess	Princess Cruises	143,700	28
Norwegian Breakaway	NCL	145,655	28.22
MSC Seaside	MSC Cruises	152,050	28.87
Anthem of the Seas	Royal Caribbean	167,800	28.87
Crown Princess	Princess Cruises	113,561	29.53
Navigator Of The Seas	Royal Caribbean	139,570	30
Harmony Of The Seas	Royal Caribbean	227,000	30.58
Queen Mary 2	Cunard Line	148,528	32.81

Final Word

It’s pretty easy to see why some cruise ships can’t access certain ports, but now you know the answer in a little more detail.

Especially when you look at that table above and see how some tiny ships have quite large drafts, and some larger ships don’t extend too far into the water. You might now realise that there are some bigger ships which can access ports which might be surprising – and you’ll know why.

At the very least, I bet you’ll be looking for the draft markings on your ship the next time you cruise!

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