How Many Cargo Ships Sink Every Year?

It is well known that working at sea can be perilous and sometimes deadly. Data from Allianz shows that 54 merchant ships were lost in 2021.

This is equivalent to around one ship lost per week. This figure does not include unreported vessel losses, such as from pleasure craft or migrant boats.

Based on UNCTAD’s global estimate of 99,800 merchant ships, this means that 0.054% of the global fleet was lost in 2021.

Another way of looking at this is that 99.946% of ships did not sink, so shipping is perhaps safer than many people think. However, the loss of these vessels is still extremely serious and shows that improvements can still be made.

Ship typeNumber of ships lost over the last decadeProportion of global ship losses over the last decade
Cargo (including container)39044%
Data from Allianz showing the proportion of global ship losses by vessel type

Cargo, fishery and passenger ships account for over 60% of ship losses over the last decade.

Fishing vessels in particular can be extremely dangerous due to the sea and weather conditions in which they sail. Fishing vessels tend to have very low freeboards, meaning that the distance between the water and the ship’s lowest deck is very small.

What causes ships to sink?

Scientifically speaking, a ship will sink when its buoyancy becomes less than its mass.

If there is an opening in the hull of the ship, for example from a grounding or a collision with another vessel, then water can enter the ship and make it heavier.

Once enough water has entered the ship, she will lose her ability to keep herself afloat as the weight of the ship becomes greater than the water it displaces.

At this point, the vessel will become more and more submerged until it sinks.

Water ingress can lead to a ship sinking

Merchant ships are required to have a document called a stability booklet, which is provided by a naval architect and gives data regarding the ship’s survivability.

A stability booklet includes information on how many sections of the ship can be filled with water before she will sink. This helps the Captain to make a decision on when a ship must be abandoned if she begins to take on water.

The causes of sinking ships

There are many reasons why a ship might experience water ingress. The most common causes include:

  • Grounding
  • Collision
  • Bad weather
  • Fire

A ship could run aground if she encounters an uncharted submerged object such as a rock, or if the ship is out of position. This could happen if the ship’s GPS fails and its navigators have failed to double-check the ship’s position.

Another plausible reason for a ship running aground is if her engines fail in coastal waters and she is forced by wind and/or tide into shallow water.

Not all capsized ships end up sinking

A collision between two ships is less likely to result in a sinking because the point of contact between the two is likely to be above the waterline, meaning that water ingress will be less severe than in the case of a bad grounding.

High seas, fire, and why some waves are more dangerous than others

High seas and strong winds can be fatal for an unprepared ship.

There are many methods of combating rough seas on a ship, for example closing external intake vents, securing hatch covers, and even filling the anchor hawsepipe with cement.

However, if a vessel is unprepared then water could enter the ship before sufficient action can be taken.

One of the most dangerous weather phenomena a ship can encounter at sea is called synchronous rolling. This occurs when a ship encounters a series of waves whose period matches the natural rolling period of the ship.

In this situation, a ship will heel over slightly because of the energy in the waves surrounding the ship. Then, before the ship can correct itself and become upright, the next wave will strike and worsen the heeling angle of the ship.

Getting out of this situation is as simple as changing the course or speed of the ship. However, if a ship’s navigation officers do not recognise that synchronous rolling is occurring, it can very quickly become too late to rectify and the ship may heel to beyond the point where she can bring herself upright again. In this case, the ship will capsize.

Fire is one of the most terrifying things that can be experienced at sea. It is up to the ship’s crew to combat the fire – they can’t call the fire brigade to fix the problem for them.

Although cargo ships are no longer made of wood, fire can still be structurally devastating to a vessel.

A fire can quickly spread out of control and, depending on the nature of the ship’s cargo, it may be necessary to immediately abandon ship. This can result in the total loss of the ship if the fire damages the vessel’s structure to the point where water enters the ship and causes it to sink. Fire is the leading cause of loss for car carriers, often caused by malfunctioning vehicles in the ship’s holds.

Is shipping getting safer?

The main dangers that seafarers have faced over the centuries have not changed. 

Training and education, coupled with greatly improved safety systems, have led to increasingly safer ships.

According to Allianz, in the early 1990s, the global fleet was losing over 200 ships a year. 

Thankfully, statistics show that shipping is in fact getting safer year on year. The number of ships lost at sea has declined by 57% in the last decade.

Data from Allianz shows that ship losses are trending downwards

The decrease in ships being lost can be attributed to a number of factors.

The introduction of the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW) in 1984 has led to greatly improved minimum standards over the decades, setting a baseline for minimum standards of training for all seafarers across the world.

The training and education of seafarers continues to improve over time, as does the competency of shipping companies themselves. The introduction of the International Safety Management (ISM) Code in 1994 has led to vast improvements in the way that ships’ safety systems and maintenance regimes are managed.

Even shipbuilding advances have contributed to reduced losses – the introduction of double-bottomed hulls has reduced the number of ships lost to grounding.

There are many more factors as to why fewer ships sink year on year, but the main difference-makers are legislative in nature. The end goal is, of course, for annual ship losses to reach as close to zero as possible.