Frederik Elting- Sea Tag Float

The Challenge

Each year, shipping containers are lost at sea as a result of storms, structural failures or handling incidents. In 2024 alone, 576 containers were reported lost, more than double the number recorded in 2023. While these losses represent only a small fraction of global container movements, the consequences are disproportionately severe.

Drifting containers can float just below the surface, creating serious collision hazards for commercial vessels and small craft. Depending on cargo, container losses also pose environmental risks through pollution or the release of hazardous materials. From an insurance perspective, the absence of reliable information about when and where containers are lost often leads to prolonged claims disputes, increased costs and underwriting uncertainty.

From 2026, the International Maritime Organization will require mandatory reporting of container losses. However, the industry still lacks a low‑cost, scalable way to make lost containers visible and identifiable once they enter the water.

 

The Innovation

SeaTag Float is a compact, passive safety device designed to make containers lost overboard visible on the sea surface. The unit is mounted externally within the recesses of a standard container and operates autonomously without electronics, power supply or crew intervention.

When immersed in water, SeaTag Float deploys a lightweight, radar‑reflective balloon approximately one metre in diameter. The balloon is tethered to the container with a short floating line, ensuring it remains close to the surface and detectable both visually and by ship radar. Two units can be installed per container to provide redundancy.

The system is maintenance‑free, designed to remain operational for several years, and secured within container recesses to avoid damage during handling. With an estimated production cost in the low double‑digit euro range, SeaTag Float is economically viable for large‑scale deployment across the global container fleet.

 

How It Was Implemented

SeaTag Float is currently in the pre‑prototype phase. The concept has been translated into a practical design using proven maritime safety technologies and materials. Engineering assessments and cost modelling have confirmed feasibility in terms of size, durability and unit economics.

The device is designed for simple integration into existing container workflows. Units could be fitted during container turnaround at depots or incorporated at the manufacturing stage, with no impact on lifting, stacking or transport operations and no requirement for crew training.

The next stage involves prototype construction, controlled water testing and pilot deployments in cooperation with insurers and shipping partners.

 

What Was the Result

Although live sea trials have not yet been conducted, analysis of comparable technologies demonstrates strong feasibility. Radar‑reflective surface markers are already used successfully in maritime search‑and‑rescue operations. Modern synthetic tethers provide proven strength and durability in saltwater environments. Stakeholder feedback confirms that compact integration and low cost are critical to acceptance.

At this stage, the result is a validated, technically sound design with a clear pathway to implementation.

 

Conclusion

SeaTag Float addresses a long‑standing gap in maritime safety and insurance risk management. Unlike electronic tracking systems, it is passive, maintenance‑free and affordable at scale. For insurers, it offers clearer evidence of container loss location and timing, reducing disputes and uncertainty. For the wider maritime community, it improves safety by increasing the visibility of drifting containers and supporting recovery efforts.

The next step is to progress from validated design to pilot deployment, enabling SeaTag Float to become a practical, global solution to container losses at sea.