How Many EPIRBs Are There On A Ship?

Emergency Position Indicating Radio Beacons are an essential piece of search and rescue technology on modern vessels. But, just how many are required to be carried on a modern vessel?

Ships are required to carry at least 1 satellite position-indicating radio beacon (EPIRB). Passenger ships may carry a second EPIRB on the bridge if their primary EPIRB is not remotely activated when their distress panel is activated.

How many EPIRBs do Cargo Ships Carry?

In accordance with SOLAS Chapter 4, cargo ships are required to carry at least 1 EPIRB. Strictly speaking, that regulation only applies to cargo ships over 300 gross tons. For the purposes of this article, however, it is safe to say that all cargo ships need at least one EPIRB.

EPIRBs are part of the ship’s radio installation. As such the precise details of what needs to be carried depends on the sea areas that the vessel is operating within.

If the ship only operates within coverage of Inmarsat satellites, it only needs to carry an Inmarsat capable EPIRB. If the ship operates outside of Inmarsat coverage, it needs to carry a COSPAS-SARSAT 406 MHz EPIRB instead.

Cargo ships that operate exclusively within Sea Area A1, only need to carry a DSC VHF 70 capable EPIRB.

How many EPIRBs do Passenger Ships Carry?

Passenger ships are subject to the same radio installation requirements as cargo ships. They also need to carry at least 1 EPIRB.

In addition, passenger ships need to have a distress panel which can send a simultaneous distress alert through every piece of radio equipment carried on board. If they use their EPIRB as a secondary means of distress alerting, they need to carry a second EPIRB located in the wheelhouse near to the distress panel.

Particularly on large passenger vessels, it is important to carry multiple EPIRBS. The primary EPIRB will be located high up on the vessel where it will float free in an emergency. It could be a distance away from the navigational bridge, so it is best to have access to another one should it be needed.

How many EPIRBs do Small Boats Carry?

Small boats are often not actually required to carry any EPIRBs at all.

Some administrations will require an EPIRB to be carried a certain distance from land. For example, Australia requires that EPIRBs are carried on all boats that proceed more than 2 nautical miles offshore. You can read the requirements by clicking here.

The requirement is only ever for a single EPIRB, however.

How many Types of EPIRB are there?

When we talk about different EPIRBs, we can either refer to different “types” or different “categories”.

There are three main types of EPIRB, which are all applicable when operating in different Sea Areas.


The most common, standard EPIRB is the COSPAS-SARSAT 406 MHz EPIRB. These beacons communicate with a global network of satellites providing worldwide coverage.

The satellites in the COSPAS-SARSAT constellation are in various orbits, so they provide coverage over the entire surface of the earth.

406 MHz EPIRBs meet all global carriage requirements, so are the only type you really need. They are the ones that you will see most often when you are looking to buy your next EPIRB.


Inmarsat E EPIRBs are different to the standard 406 MHz EPIRBs in that they use a different constellation of satellites.

They send signals to geo-stationary Inmarsat satellites. As the satellites are in a geo-stationary orbit, they do not provide worldwide coverage. They are only effective in latitudes between 70°S and 70°N.

As such, Inmarsat E EPIRBS only meet carriage requirements when you are within Sea Areas A1, A2 and A3. It is easy to remember because the definition of Sea Area A3 is the area which falls within the footprint of geo-stationary Inmarsat satellites.


VHF CH70 EPIRBs are different to the other two in that they operate on VHF rather than with satellites.

They still fit within the definition of an Emergency Position Indicating Radio Beacon because they use radio waves to indicate your position. The fact that they operate on VHF just impacts the sea areas in which they can be used.

You can only use VHF CH70 EPIRBs within Sea Area A1. This makes sense as Sea Area A1 is defined as the area in which you are within VHF coverage of shore stations.

How many Categories of EPIRB are there?

There are two categories of EPIRB, Category 1 and Category 2.

Category 1 EPIRBs

Category 1 EPIRBS are designed to be automatically released and activated should a vessel sink.

They usually achieve this using a HRU (hydrostatic release unit). The HRU automatically cuts an EPIRB free once it has been submerged to a depth of 2-4 metres. Automatic activation is achieved using underwater contacts which detect the presence of salt water.

The other important consideration for a Category 1 EPIRB is its mounting position. It needs to be mounted in such a position that it would float free in an emergency. Usually this is high up on a ship, clear of all overhead obstructions.

Category 2 EPIRBs

Category 2 EPIRBs are the same as Category 1 except they do not float free or automatically activate.

You will often find that a ship has two identical EPRIBs, one Category 1 and one Category 2. The Category 2 EPIRB will just be the one that is located inside the wheelhouse. It is identical to Category 1 in every respect, except its storage location.

When we discussed passenger ships earlier, the second EPIRB that they carry will be a Category 2.

How Many EPIRBs Should I Carry on my Boat?

I would always ensure I carry at least 1 EPIRB.

On a small boat that is not legally obliged to carry an EPIRB, I would be happy to swap the EPIRB for a PLB. You can read an entire article about the differences between EPIRBs and PLBs here: What Is The Difference Between An EPIRB And A PLB?

The reason for this is that the cost of both EPIRBs and PLBs has come down so much in recent years. It really is quite a small price to pay for a device that can call for help from anywhere in the world.

The EPIRB has its own power supply, its own aerial, and does not rely on any other inputs at all. It is also the one piece of equipment that could automatically call for help in an emergency. 

There are always stories in the news about people being rescued from upturned boats when their EPIRB has activated. You can read one from Cornwall Live here: Pair Rescued From Capsized Boat 45 Miles Out At Sea In The Middle Of The Night.

The article tells the story of a capsized trimaran where their EPIRB alerted the coastguard so they were rescued after a few hours.

When Might I Carry Multiple EPIRBs?

On my own boat, I wouldn’t consider carrying multiple EPIRBs. The reason for this is that I would prefer to have a single EPIRB for the vessel, and possibly a PLB for crew members.

The PLBs can act as a back up to the EPIRB should anything catastrophic happen. In addition, you get the extra protection of being able to locate any crew members that fall overboard.

A combination of EPIRB and PLB for a personal boat seems to offer enough redundancy, but is sensibly balanced with the cost of owning and servicing multiple beacons.