Why are MRUs important for helicopter deck monitoring?
Motion Reference Units (MRUs) are critically important for Helideck Monitoring Systems (HMS) because they provide precise, real-time measurements of the vessel's or platform's motion. Safe helicopter landings and takeoffs depend heavily on understanding the dynamic movement of the helideck, particularly its roll, pitch, and heave.
An MRU accurately measures these key parameters, delivering essential data to the HMS. This information allows the system, pilots, and deck crew to assess whether the helideck's motion is within the established safe operational limits. Without accurate motion data, attempting landings or takeoffs, especially in challenging sea conditions, poses significant safety risks.
Norwegian Subsea MRUs, such as the MRU Marine (IP68 rated for deck mounting) or the MRU Ex (for hazardous areas), deliver the high accuracy, reliability, and robustness required for this safety-critical application. Our sensors utilize advanced algorithms and state-of-the-art MEMS technology, validated in real sea conditions, ensuring trustworthy data for Helideck Monitoring Systems, thereby enhancing operational safety. Our MRUs meet the requirements of Cap 437 (CAP 437: Standards for offshore helicopter landing areas).
Related products

Usage area
50 m depth, IP 68
Connectors
Lemo or SubConn 8 or SubConn 16
Roll & Pitch accuracy
- 3000±0.05°
- 6000±0.02°
- 9000±0.01°
Heave accuracy
5 cm or 5.0%

Usage area
Hazardous areas
Connectors
Pigtail cable
Roll & Pitch accuracy
- 3000±0.05°
- 6000±0.02°
- 9000±0.01°
Heave accuracy
5 cm or 5.0%
Further reading

MRUs for vessel performance optimisation in focus at Europort 2025

Research Project to Test Value of MRU Data for Vessel Performance and Carbon Reduction

Advanced motion compensation for sonars introduced at Ocean Business 2025
Related questions
- Read the full answerWhat is the purpose of the MRU in classed vessels?The MRU (Motion Reference Unit) monitors vessel motions to evaluate risks related to sloshing and structural fatigue in cargo containment systems. It supports a condition-based inspection regime under DNV’s Alternative Survey Programme (ASP). 
- Read the full answerThe MRU Marine is IP-68 rated with Lemo connectors and LEDs. The Marine SW supports 50m depth, uses SubConn connectors, and comes in two versions differing by available output combinations. 
- Read the full answerInclinometers offer basic static tilt readings, Roll & Pitch Sensors suit moderate motion, while VRUs provide precise roll and pitch in dynamic conditions. Choose based on motion complexity, accuracy needs, and budget. 
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