Monitoring systems › Structural and Motion Monitoring › Vessel Motion Monitoring Systems
Vessel Motion Monitoring Systems (VMMS)
The limiting factor measured directly — so the decision to transfer is made on vessel motion, not on significant wave height.
Vessel motion is often the primary operational and safety-limiting factor when working offshore from a workboat, particularly during a personnel transfer. Accurate motion monitoring during those operations can significantly increase the operational window, and is often the difference between a successful transfer and an aborted one.
VMMS is built as an HSE support system as much as an operational one: the same measurements that guide the Captain in the moment become the record used afterwards for statistics, documentation and investigation.
[Photo to come — a crew transfer vessel at a turbine boat landing, or the VMMS display on the bridge during a transfer.]
What it gives you
Motion, not wave height
The parameter that actually limits the operation, measured on the vessel, rather than a sea state inferred from a forecast.
A wider operational window
Knowing the motion at the landing point in real time lets marginal conditions be worked rather than written off.
Guidance the Captain can act on
Motion indices, transfer risk values and traffic-light indicators, either as advice or tied to access control.
A record after the fact
Everything stored locally for statistics, documentation and incident investigation, with optional black-box storage.
Designed for critical offshore operations
VMMS is used both in real time and for post-operation analysis. In the moment it supports the decision to go or hold; afterwards it supplies the motion data behind statistics, documentation, and incident or accident investigation.
Rather than relying solely on significant wave height, VMMS lets the crew watch the vessel motion parameters that are usually closer to the actual operational risk. Meteorological parameters and other relevant information can be added as optional features.
Typical applications
Wind farm workboats
VMMS is widely used on wind farm service vessels, supporting two distinct phases of the same trip:
- Transit — from shore to the wind farm. Motion trend displays are used actively to reduce motion discomfort and seasickness, so personnel arrive fit for work.
- Landing — during personnel transfer to the turbine. Motion indices, transfer risk values and traffic-light indicators reduce the risk of injury at the moment of stepping across.
Offshore oil and gas, and marine vessels
The same system applies to offshore support vessels and other marine assets where safe operation depends on knowing the vessel’s motion and the conditions around it accurately — lifting, gangway operations, ROV work and anything else with a motion limit attached to it.
What changes between the two is the configuration: where the sensors go, which parameters are put in front of the crew, and what the limits are set to.
[Screenshot to come — the VMMS display with the traffic-light indicator and heave-rate readout.]
System configuration and functionality
A basic VMMS is one, two or three motion sensors and a system computer that measures, calculates and displays the parameters the Captain needs when making the call.
Standard and optional measurements include:
- Full six degrees of freedom: pitch, roll, heave, surge, sway and yaw
- Heave and heave rate measured at the landing point and calculated in real time
- Accelerations measured in passenger cabins for comfort analysis
- Horizontal motions — surge and sway
- Impact forces, bow pressure, hawser tension and other landing forces
A simple traffic-light system can be used for operator guidance or for access control, either automatically or under the Captain’s supervision.
Integration, expansion and data handling
A VMMS scope can be expanded to include accelerometers and inclinometers, meteorological sensors, down-looking radar for wave and air-gap measurement, and structural and environmental sensors.
The motion sensors can be integrated with other monitoring systems for online monitoring or long-term recording, and data can be sent to shore or to another site for tracking and coordination where a suitable communication link exists.
All data can be stored locally for later analysis, statistics and investigation. Optional external storage, including free-floating data buoys, adds black-box functionality. Systems are built to the client’s specification and can be expanded later to meet new operational demands, rules and regulations.
Built on proven offshore experience
WISE Group has delivered motion monitoring for vessels and offshore platforms for many years — motion in all six degrees of freedom, vibration, inclination, wave monitoring with or without heave compensation, and air-gap measurement. Heave-rate calculation for safer operation is included as standard.
VMMS builds on more than 20 years of developing Helideck Monitoring Systems for offshore vessels and platforms, and on the safety improvements those systems have delivered. Used proactively as part of HSEQ work, VMMS contributes to significantly improved safety standards during critical offshore operations.
Where to next
Vessel Motion Monitoring sits in Structural and Motion Monitoring, one of six monitoring areas WISE Group delivers.
In this area: Structural Health Monitoring · Condition Monitoring
Related systems: Helideck Monitoring · MetOcean and weather monitoring · Excursion monitoring
Also useful: The WISE AIM motion sensor · Sensors and instruments · Service and support
Get in touch
Tell us about the vessel and the operation it has to support — the type of boat, where the transfer or lift happens, and what the current limits are set against — and we will come back on what a system would need to measure and where the sensors would sit. You can also contact us directly.