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Cruise Ship Anchors – Function, Size, Weight, and Uses

If you have seen a cruise ship you may be wondering if they have anchors. The majority of boats and ships do but with the vast size of cruise ships are anchors needed in the same way?

Cruise ship anchors usually can’t be seen from the shore and if you’ve been on a cruise ship it’s unlikely that you have spent too much time wondering about how the cruise ships stay in one place.

I recently saw a replica of the Titanic’s anchor which made me wonder if modern ships still have anchors.

Do Cruise Ships Have Anchors?

Modern cruise ships do have anchors. Dynamic positioning technology has reduced the need for traditional anchors but has not eliminated their use completely. Cruise ship anchors are usually between 10-20 feet in length and weigh between 10 and 20 US tons. Most modern cruise ships will have more than one anchor.

Cruise ship anchors are used to keep the cruise ship in a stationary position. This is often needed when a ship stops out to sea.

 cruise ship anchors anchored in fjord
Princess Cruise ship anchored in the Norwegian Fjords

Do Cruise Ships Have Multiple Anchors?

The majority of ships have more than one anchor. It is common for ships to have two anchors, one on the port side and one on the starboard side of the ship.

There are a few reasons for this:

  • In certain circumstances it makes sense to use an anchor that is on one side of the ship over the other.
  • If an anchor became damaged, broke or was lost the ship needs to have another anchor that can be used as backup.

In addition to two working anchors, some ships will have a third backup anchor. This may not be the full size or weight of the main anchors.

When a ship uses both anchors at the same time and they are both anchored ahead, this is known as an open moor.

The below photo shows the Marella Discovery 2 using both anchors.

cruise ship using two anchors
Photo: Mark Evans

When do Cruise Ships Use Their Anchors?

Anchors are used to hold a ship in place. If a ship is unable to dock in a port due to shallow water it may be necessary for the ship to hold a position out to sea and to transport its passengers using tender boats.

Having to take a tender boat to land is a very common part of cruising. Guests are usually able to see ahead of time if the ports that they are visiting will require tendering.

I do enjoy tendering when I cruise but on occasion, it can mean long wait times. Tendering into port also increases the chance of a port being cancelled if the weather is bad. Cruise ships cannot risk tendering their passengers to land if they are unsure that they’ll be able to get them back later.

To learn how to spot tender ports and how to make the process as efficient as possible, check out this post: Cruise Ship Tendering – 5 Tips You NEED to Know.

How do Cruise Ship Anchors Work?

Cruise ship anchors dig into the seabed and provide a contact point for the ship.

When it comes to large ships, it isn’t just the anchor that holds the ship in place. The anchor is on the end of a long and heavy chain and the weight of this chain on the seabed helps to hold the ship in place. Each piece of the chain can be incredibly heavy.

The longer the anchor chain the more movement the ship can withhold. If the anchor chain was very short and a the ship slightly this may cause the anchor to break free. With a long chain the ship is able to move slightly without the anchor needing to come out of the seabed. The chain will simply become less slack.

Will Cruise Ships Always Need Anchors?

Modern technology has reduced the need for anchors but hasn’t completely eliminated it. Many modern cruise ships have ‘dynamic positioning’ meaning that they use propulsion and thrusters instead of anchors to maintain a steady position.

There are many benefits to using dynamic positioning over traditional anchoring including:

  • Increased manouverability
  • Quick to set up (and to stop)
  • Seabed conditions and water depth don’t matter

Maintaining the position of a ship in this way may be better for the seabed as an anchor doesn’t have to be dropped but it does use more fuel and therefore produce more emissions. The initial cost to install this technology is also high.

Dynamic positioning was created in the 1960s for offshore drilling but it is a relatively new piece of cruise ship technology.

How Big are Cruise Ship Anchors?

Cruise ship anchors usually range from 10ft to 20ft in length. The Titanics anchor was 18ft 6 inches in length and the cast steelhead of the anchor was 10ft 9 inches.

In most cases, the size of the anchor directly correlates with the size of the ship.

cruise ship anchor adventure of the seas
Photo: Corey Seeman

How Much do Cruise Ship Anchors Weigh?

As a general rule cruise ship anchors tend to weigh between 10 and 20 US tons. The Titanics anchor was 16 US tons and many of the large modern large ships have anchors that weigh vastly more.

The largest ship detailed by the iacs equipment number calculation would require a 46,000kg anchor. A ship with a 46 metric ton anchor would need an anchor chain of at least 770 metres.

To put that into perspective the largest elephants weigh around 5 tons, so that’s over 9 elephants!

The below table shows the correlation between anchor weight and chain length.

Note, metric tons are different from US tons.

1 metric ton is 1000 KG.

1 US ton is 907 KG.

Anchor WeightChain Length
660 kg (0.7 US tons)302.5 metres
4320 kg (4.7 US tons)550 metres
10500 kg (11.6 US tons)660 metres
20000 kg (22 US tons)770 metres
46000 kg (51 US tons)770 metres
Ship Anchor Weight to Chain Length Correlation

What Would Happen if a Cruise Ship Lost it’s Anchor?

The majority of cruise ships do have more than one anchor and would be able to maintain their position using just one. Many modern cruise ships would be able to use dynamic positioning if all anchors were lost for some reason.

It’s worth noting that anchors very rarely get lost.

If a ship had lost all of its anchors and was unable to dynamically position the ship would be unable to maintain a position when out to sea.

In this situation, the ship would be either forced to dock in port or to keep sailing.

Cruise Ship Anchor Impact in 2020 and 2021

Due to the 2020 cruise industry shut down a number of cruise ships had to anchor out to sea for long periods of time. The long lengths of time that the ships would be at sea meant that anchoring was a necessity.

One area that was affected by this was the south coast of England. There are no laws that say that cruise ships cannot drop anchor when out to sea and as a result this is how most ships spent the year.

It was too expensive to keep the ships docked and there wasn’t enough dock space in many places to accommodate the number of ships without anywhere to go.

The impact of the ships anchoring out to sea is still being investigated.

The MSC Bellissima’s anchor can be seen in the above photo

Cruise Ship Anchors (Sometimes) Have New Lives!

In the majority of cases, when a cruise ship is scrapped the anchor is scrapped along with the ship. There are a few examples though where cruise ship anchors have found new lives after their ship was scrapped.

Due to the weight and size of cruise ship anchors, it is difficult to use them for another purpose. One use of anchors has been as monuments or statues.

An anchor from the Queen Elizabeth 2 (1 of 2 anchors) currently is a landmark in Southampton. The anchor is 4.3m (14ft) by 2.7m (9ft) and weighs 13 tons.

cruise ship anchor queen elizabeth 2 in southampton
Photo: Daniel Gosling

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