Ultra-low-noise accelerometer for marine structural monitoring

0.7 µg/√Hz noise density. Ready-to-deploy marine housing. Built for the signals that standard accelerometers can't see.

ACC Marine

Ultra-low-noise measurements

Exceptionally low 0.7 µg/√Hz RMS noise density combined with very high in-run bias stability enabling new applications

Easy integration

Ethernet, serial communication and industry-standard protocols including Modbus TCP, Modbus RTU and EtherNet/IP. Configuration software supports setup, monitoring and firmware updates.

Robust and Waterproof

Compact waterproof aluminium housing for marine environments. The ACC Marine SW variant can be used in up to 50 m water depth.

Ultra-low-noise accelerometer with noise density of 0.7 µg/√Hz RMS

Product overview

The ACC Marine is a 3-axis accelerometer with a noise density of 0.7 µg/√Hz RMS — low enough to resolve structural motion that standard sensors cannot distinguish from noise. It combines this measurement performance with high bias stability and industrial communication interfaces, making it suitable for permanent structural monitoring without custom signal conditioning or external housing.

The ACC Marine (IP68) installs in dry or protected locations. The ACC Marine SW is rated for the splash zone and continuous deployment at up to 50 m water depth — enabling direct mounting on submerged structures without additional enclosures.

Typical installations include floating offshore wind platforms, offshore jackets and monopiles, subsea templates, FPSOs and vessels. In all these environments, the combination of ultra-low noise and ready-to-deploy marine packaging reduces both measurement uncertainty and integration effort.

Why ultra-low-noise matters

Large marine and offshore structures often move at low frequencies and with very small acceleration levels. With standard accelerometers, these small signals can be difficult to separate from sensor noise.

ACC Marine has a noise density of 0.7 µg/√Hz RMS, allowing it to detect low-amplitude vibration with high confidence.
This makes it suitable for structural monitoring, fatigue assessment, natural frequency tracking, resonance detection and digital twin input.

Low noise gives better data quality — especially when small changes in structural response matter.

What the data can be used for

Early detection of abnormal structural behaviour
Vibration monitoring
FFT and spectral analysis
Natural frequency tracking
Fatigue assessment
Resonance detection
Anomaly detection
Model validation
Digital twin updating

Standard accelerometers vs Ultra-low-noise accelerometer

Typical applications

Offshore structures

Monitor jackets, monopiles, topsides, bridges, walkways and support structures. ACC Marine provides high-resolution vibration data for structural response, resonance behaviour and changes in stiffness or damping.

Subsea templates and marine structures

Use the ACC Marine SW variant in up to 50 m water depth. Typical use cases include vibration monitoring, impact detection, operational movement and low-frequency structural response.

Floating offshore wind

Monitor the dynamic response of floating wind platforms, towers, transition pieces and substructures. The data can support fatigue assessment, model validation, natural frequency tracking and digital twin input.

Vessels and floating assets

Monitor hull and deck response, wave-induced vibration, machinery-induced vibration and fatigue-relevant motion on vessels, barges, FPSOs and other floating assets.

Standard accelerometers vs ACC Marine

Standard accelerometers

Standard accelerometers are well suited for many vibration monitoring tasks, especially when the vibration levels are high.

However, offshore and marine structures often produce low-frequency, low-amplitude motion where sensor noise becomes a limiting factor.

Standard accelerometer

General vibration or event detection
Suitable for higher-amplitude vibration
Lower sensor cost
Mainly used for alarms and basic trends

Ultra-low-noise accelerometer

ACC Marine - Ultra-low-noise accelerometer, is designed for measurement points where signal quality, long-term stability and marine integration are critical.

ACC Marine is not intended to replace every standard accelerometer.

ACC Marine

High-resolution structural monitoring
Designed for small acceleration levels
Higher data quality and reduced integration risk
Suitable for fatigue, modal analysis and digital twins

Specifications

Download product brochure

Casing

Environment

Marine: IP68
Marine SW: 50 m water depth

Casing material

Marine Anodized Aluminum 6061-T6

Dimensions

154 x 86 x 67 mm

Weight

1.2 kg

Interfacing

Connector

Marine: Lemo 16 pins
Marine SW: SubConn 8 pins

Ports

Marine: Ethernet, RS-232, RS-485 (422), PPS
Marine SW: Ethernet & RS-232, Ethernet & 2-wire RS-485

Communication

Marine: TCP, UDP, Modbus TCP, ethernet/IP, Serial, Modbus RTU
Marine SW: TCP, UDP, Modbus TCP, ethernet/IP
Marine SW16: TCP, UDP, Modbus TCP, ethernet/IP, Serial, Modbus RTU

Output frequency

0 - 100 Hz

Performance

Range

± 15 g

Scale factor

6.00E-05 mg/LSB

Misalignment axis to axis

0.1 °

Nonlinearity

0.03 % FS

Initial error

2 mg

Bias repeatability

3 mg

In run bias stability

0.2 μg

Velocity random walk (VRW)

0.00012 m/s/sqrt(h)

Noise density

0.7 μg/sqrt(Hz) RMS

Frequency bandwidth 3dB

400 Hz

Power & interface

Power consumption

6 W

Supply voltage

9 - 36 V DC (24 V nominal)

Internal storage

32 GB

Data protocols

Custom NMEA, ASCII and Binary, and many more.
Read more

Configuration protocols

GET/SET through telnet, serial port and MRU configurator.
Read more

Time synchronization

Sync to host PC, Sync to NTP server, Sync to PPS

Environmental specifications

Temperature range

Operating: -40 to +85 °C
Storage: -40 to +85 °C

Electromagnetic compatibility

IEC 60945/EN 60945
(immunity/emission)

Vibration

IEC 60945/EN 60945

Max shock

2000 m/s2 (half-sine 0.5 msec)
non-operational (10 ms peak)

MTBF (computed)

100 000 h

Easy to use

ACC Marine can be configured using Norwegian Subsea’s Configurator. Communication ports, protocols, output format and system settings can be defined from a simple user interface.

The software can also be used to monitor outputs in real time, check diagnostics and update firmware.

This makes ACC Marine suitable for both stand-alone measurement setups and integration into larger monitoring systems.

Read more about the Configurator SW

Some of the applications where our ACC Marine are used

Floating Wind Base Motion Monitoring

Monitoring the movements and structural integrity of floating wind foundations, including both the base and turbine, along with the anchoring system, is crucial.

Ship Motion Monitoring

Precise motion measurements are essential for vessel digitalisation, supporting fuel optimisation, route planning, cargo safety and structural health.

Subsea Surveys

Subsea surveys often demand precise tilt measurements (roll and pitch) for various purposes, such as installation tasks or continuous monitoring of tilt changes and deflections in subsea structures.

All applications