Types Of EPIRB Simplified For Sailors
Emergency Position Indicating Radio Beacons (EPIRBs) are type of emergency beacon critical for maritime safety.
They come in mainly two types: Category I and Category II.
These beacons play a vital role in locating vessels in distress by sending signals to search and rescue satellites.
Types of EPIRB in the Marine Industry
EPIRBs are designed to signal distress and pinpoint locations to facilitate swift rescue operations. Your knowledge of EPIRBs helps ensure safety at sea, whether for commercial vessels or personal watercraft.
Category I EPIRB

Category I EPIRBs are designed for automatic activation. They deploy automatically when they come into contact with water, thanks to their hydrostatic release unit (HRU). These beacons are usually mounted on a vessel and will release themselves from their bracket when immersed in water, typically at depths of 1.5 to 4 meters. The advantage of Category I EPIRBs is their ability to begin transmitting a distress signal even if you are unable to activate them manually, which could be vital in situations where you become incapacitated.
Category II EPIRB

Category II EPIRBs require manual retrieval by a person. They can also be activated automatically if water activation is built in, but this is not mandatory. These EPIRBs are typically chosen for smaller boats or as a backup to a Category I unit, as they offer a more cost-effective option for mariners who are confident in their ability to activate the beacon during an emergency.
Differences Between Category I and II
Key differences between Category I and II EPIRBs include their activation methods. Category I beacons are equipped with a hydrostatic release, intended for automatic operation upon submersion, while Category II beacons rely predominantly on manual activation.
When picking an EPIRB for your boat, consider factors such as the size of your vessel, the typical number of crew, and the voyages you plan to undertake.
Personal Locator Beacon (PLB)

Personal Locator Beacons (PLBs) are smaller, portable emergency transmitters carried by individual persons. Unlike EPIRBs tailored for vessel use:
- PLBs are registered to a person, not a vessel.
- They can be attached to a sailing life jacket or safety kit, making them a key asset for personal safety.
PLBs can also be used in conjunction with Emergency Locator Transmitters (ELTs), which are aviation-specific, to aid in cross-platform SAR operations where vessels and aircraft are involved.
Differences Between an EPIRB and a PLB
There are several differences between EPIRBs and PLBs. However, the main distinction is that EPIRBs are specifically designed for marine environments and are registered to a vessel. Alternatively, PLBs are registered to an individual and are typically used on land as well as for marine.
Overview of How EPIRBs Work
All EPIRBs function in exactly the same way regardless of type along with the global search and rescue infrastructure, leveraging satellites for detection and location pinpointing.
EPIRB Registration and False Alerts
Proper registration of your EPIRB is not just for compliance, but to help manage and reduce false alerts which can lead to unnecessary search and rescue operations.
Registration ensures that in the event of an emergency, rescuers have the vital information they need to assist you.
📝 Author’s Note: Check out our full guide on how to register an EPIRB.
Legal Conventions and Requirements
Category I and II EPIRBs are governed by international conventions designed to protect lives at sea.
The most prominent framework is the International Convention for the Safety of Life at Sea (SOLAS), which is a standard for all commercial shipping.
SOLAS requirements stipulate that ships must be equipped with a Category I EPIRB, which automatically deploys and activates when submerged in water.
The Global Maritime Distress and Safety System (GMDSS) further mandates that certain classes of ships carry these devices to expedite rescue operations by Rescue Coordination Centers (MRCC).
Each country often reinforces international conventions with its own national legislation. For example, in the United States, the Coast Guard sets regulations for EPIRBs that require all commercial vessels under U.S. jurisdiction to carry and properly maintain them.
Compliance with these regulations is crucial not only for adherence to the law but also for ensuring the device’s functionality in emergencies.
NOAA also plays a role, as EPIRBs must be registered with them, which is a free service that can significantly speed up rescue response times.