EPIRB Hydrostatic Release Units Explained

A hydrostatic release unit is a critical component in the automatic deployment of a float-free EPIRB. It’s designed to activate based on water pressure at a predetermined activation depth.

The HRU releases the EPIRB only when a vessel is sinking, allowing it to reach the surface and transmit a distress signal.

This device is essential for safety at sea, ensuring that, even if you’re unable to manually release the beacon, the EPIRB will still deploy.

Types and Mechanisms

Before delving into the specifics, understand that hydrostatic release units (HRUs) come in various types, each with unique mechanisms designed to enhance the safety capabilities of maritime equipment in emergencies.

Differences Between HRUs

They vary primarily in their release depths and the mechanical intricacies that dictate this action. A standard HRU, such as the Hammar H20, is engineered to activate automatically at water depths typically between 1.5 and 4 meters.

These devices are essential for the auto-deployment of life-saving equipment like life rafts and EPIRBs.

HRUs utilize water pressure to trigger a release mechanism at certain depths, thereby ensuring that your emergency equipment is freed at critical moments without the need for manual intervention.

Patented Technologies in HRUs

One notable advancement in HRU technology is the patented rod system found in some models. This specific design plays a pivotal role in the precise and reliable release of attached safety devices.

Furthermore, brands like Hammar have developed their units, incorporating distinctive HydroFix technology.

These patented elements work to improve the HRUs’ responsiveness to varying water pressures and depths, which could mean the difference between a timely life raft deployment and a compromised safety situation.

Installation and Maintenance

To ensure the efficacy of your EPIRBs HRU, proper installation and maintenance are paramount.

⚠️ Remember: Incorrect installation can impede the proper function of the HRU, potentially jeopardizing safety at sea.

For any EPIRB installation, your HRU must:

1️⃣ Secure the EPIRB firmly within its bracket to prevent accidental release.

2️⃣ Connect the HRU according to the manufacturer’s instructions, ensuring that it fits snugly without any obstructions.

Maintenance is critical and should be performed annually to ensure your HRU is in optimal condition. Key points include:

  • Verifying the unit’s secure attachment and checking for signs of wear and corrosion.
  • Noting the expiry date and planning a replacement before it lapses.

The service life of your HRU is typically two years, after which it must be replaced without delay.

Adhering to the manufacturer’s guidelines is non-negotiable for both installation and maintenance.

EPIRB manufacturers provide detailed instructions that you should follow diligently.

You must read and understand the manual provided by the manufacturer which outlines the maintenance activities that align with specified procedures to maintain the warranty and ensure device reliability.

Regulatory Compliance and Safety Standards

Critical emergency equipment must comply with international and national regulatory standards. This includes your EPIRB and its HRU.

SOLAS Requirements

Under the Safety of Life at Sea (SOLAS) convention, it’s mandatory for passenger ships and merchant vessels of 300 gross tonnage and upwards to be fitted with HRUs.

Here’s a quick breakdown of key SOLAS requirements for your HRU:

Automatic DeploymentHRUs must automatically release life-saving equipment at pre-determined depths.
Regular MaintenanceInspect and replace HRUs according to the manufacturer’s expiration date or at least every two years.
Markings and IndicationsClear and durable markings for expiration date and instructions.

USCG Approvals

The United States Coast Guard (USCG) has their own approval processes for HRUs which Must comply with regulations, including proper installation and functionality checks

For worldwide approval, equipment must meet or exceed these agencies’ standards, which indicate rigorous testing for reliability and performance:

Only use safety equipment that carries proper certification to guarantee compliance and effectiveness in critical situations.

Leading EPIRB HRU Manufacturers

When choosing an Emergency Position Indicating Radio Beacon (EPIRB) hydrostatic release unit (HRU), you need to be aware of the reputable manufacturers and the specific features each brand offers. Your safety at sea may depend on these devices, so selecting the right EPIRB HRU from a trusted brand is crucial.

This brand stands out for its Hammar H20, widely used by the world’s leading EPIRB manufacturers. Known for reliability, the Hammar H20 ensures that EPIRBs are deployed successfully due to its tension-unaffected release mechanism

Hammar H20: Specifics of this model include:

  • Unaffected by white rope sling tension
  • Breaking strength of the white rope sling: 15kN

As a prominent player in the safety and survival equipment industry, McMurdo offers advanced HRUs designed to work seamlessly with their EPIRBs, focusing on innovation and compliance with safety standards.

McMurdo: Features may include:

  • Compatibility with various EPIRB models
  • Compliance with global maritime safety regulations

Accessories and Additional Equipment

When preparing your EPIRBs HRU you must remember two critical aspects: secure housing options like Sea Shelter™ and emergency and spare parts availability.

A Category I EPIRB benefits greatly from using a Sea Shelter™ bracket, which is a storage solution specifically designed for these devices.

These brackets work in tandem with the HRU for automatic release in water depths between 1.5 and 4 meters.

A proper housing unit, such as the Sea Shelter™, is a one-time investment that usually doesn’t incur additional costs given its no maintenance design.

In an emergency, your reliance on the EPIRB’s hydrostatic release mechanism underscores the importance of having spare parts readily available.

Despite the no maintenance aspect of an HRU it is prudent to keep spare units on hand. This means that you can replace one, should it be deployed or reach its expiry date.

Spare mounting kits may be less critical but are worth keeping for unexpected instances.

Frequently Asked

The hydrostatic release unit (HRU) on an EPIRB typically has an expiration period of two years. You must replace the unit by this time to ensure continued function in case of an emergency where your vessel is submerged.

The HS code, or Harmonized System code, for hydrostatic release units is specific to the country and the classification system they use.

You will need to check with your local customs authority or a shipping and handling service to find the exact code relevant to your region.

I’m the founder and chief editor here at Sailing Savvy. I spent a decade working as a professional mariner and currently, I mix those experiences with digital publishing. Welcome, and I hope that we can be the hub you need for safe passage.