Ship Motion Monitoring
Precise motion measurements are essential for vessel digitalization, supporting fuel optimization, route planning, cargo safety and structural health.
Ship Motion Monitoring
Accurate Motion Measurements Are Essential for Vessel Performance Optimization
Many are unaware of the crucial role that Motion Reference Unit (MRU) measurements play in optimizing propulsion and reducing fuel consumption. MRU data is primarily needed to establish the correlation between sea conditions—such as waves—the vessel's response, and the main engine (ME) consumption.
Currently, 80% of vessels do not have MRU motion measurements available.
With the ongoing IMO reporting requirements, most vessels have flowmeters hardwired to their chosen vessel performance software. However, this is not the case for MRUs.
Install MRUs on your vessel today to further improve vessel performance and reduce climate emissions.
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Why a Norwegian Subsea MRU is exceptionally suitable for ship motion monitoring
The NORSUB MRUs reliably and accurately measure all six degrees of freedom year after year. Additionally, measurement data can be logged internally and downloaded as needed. Statistical features, such as significant amplitude and peak frequency over a moving window, can also be measured. For example, the significant heave motion amplitude and peak period during the last hour can be selected as an output measurement.
The NORSUB MRUs are designed for easy installation and use. They are plug and play devices and can be delivered with a junction box or with regular Ethernet (RJ45) connectivity, such as the NORSUB eMRU series. This streamlined approach reduces cable and installation costs, providing a cost-effective solution for ship motion monitoring applications.
MRUs designed for your needs
Norwegian Subsea produces industry-leading Motion Reference Units (MRUs) for subsea, marine, and land applications. Our MRUs are robust and affordable, and offer high-accuracy performance, along with a plug-and-play interface.
Explore our productsRelated questions
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What is the difference between the MRU Marine and MRU Marine SW?
- The MRU Marine has an IP-68 rating, uses a Lemo 16-pin connector and has indicator lights.
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When navigating the complexities of motion sensing and navigation systems, it is essential to understand the distinctions between devices and systems like Inertial Measurement Units (IMUs), Inclinometers, Roll & Pitch sensors, Vertical Reference Units (VRU), Attitude and Heading Reference Systems (AHRS), Motion Reference Units (MRUs), Gyrocompasses, and GNSS-Aided Inertial Navigation Systems (GNSS/INS). Each serves specific purposes and offers different levels of functionality, accuracy, and application scope.
Gyrocompass
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The MRU Compact uses a standard RJ45 ethernet cable where power is supplied through Passive PoE (Power over Ethernet). In most cases you cannot connect the MRU directly to a an ethernet switch with PoE, since most of these are Active PoE.
We normally supply your first MRU Compact with a start kit containing a POE RJ45 spliter socket. You will only need standard RJ45 cat5 ethernet cables to connect the MRU to the spliter socket and the spliter socket to your PC or ethernet switch.
Further reading
Advanced motion compensation for sonars introduced at Ocean Business 2025
MRUs for vessel performance optimisation in focus at Europort 2025
Research Project to Test Value of MRU Data for Vessel Performance and Carbon Reduction
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
IP 65
Connectors
RJ45 or RJ50
Roll & Pitch accuracy
- 3000±0.05°
- 6000±0.02°
- 9000±0.01°
Heave accuracy
5 cm or 5.0%