Whole-body vibration & impact monitoring.

Impact monitoring answers questions about a particular shock: how large it was, when and where it occurred, and how many similar events took place.

This can be valuable for investigating incidents, comparing driving or identifying loads on the vessel and its equipment. But a low impact count does not demonstrate low whole-body vibration exposure.

• Peak acceleration
• Impact count and frequency
• Time and position of events
• Event investigation

Whole-body vibration assessment considers the continuous, frequency-weighted vibration reaching the occupant. The working period matters: moderate vibration sustained over hours may be significant even when no dramatic impact is recorded.

VIMMS reports recognised ISO 2631-1 metrics—including weighted RMS, vibration dose value and daily exposure A(8)—to describe that different form of risk. UK maritime guidance gives an A(8) exposure action value of 0.5 m/s² and exposure limit value of 1.15 m/s² for whole-body vibration.

• Frequency-weighted RMS
• Vibration dose value (VDV)
• Daily exposure A(8)
• Time and measurement coverage

A useful assessment needs reliable measurement, sufficient coverage and operational context. Results can then support decisions about routes, speed, shift planning, seating, training and vessel design.

VIMMS supports this process; it does not replace a competent risk assessment or define a vessel as safe or unsafe.

• Compare exposure with action values
• Investigate the cause, not only the result
• Record the control measures taken
• Review whether those measures worked

Workboat Code Edition 3 section 22.3.4 requires ambient sea conditions and whole-body vibration to be continually assessed throughout the voyage.

Workboat Code Edition 3 section 25.4.1 requires vessels intending to operate at high speed or in a planing mode to comply with the Merchant Shipping and Fishing Vessels (Control of Vibration at Work) Regulations 2007 and MGN 436. MCA guidance identifies ISO 2631-1 as an appropriate method for measuring and evaluating exposure.

The Regulations set an eight-hour daily WBV exposure action value (EAV) of 0.5 m/s² A(8) and an exposure limit value (ELV) of 1.15 m/s² A(8).

Impact records remain useful, but they do not calculate a person's WBV exposure. VIMMS keeps impact and frequency-weighted exposure evidence separate, helping managers assess both forms of risk and document the operational response.

• Continual voyage assessment
• Complies with ISO 2631-1
• Real-time feedback
• Automatic alerts

The value of WBV data is not the number alone, but the decision it supports. VIMMS shows when exposure approaches the action or limit value and preserves the operational context needed to investigate the cause.

Managers can use that evidence to adjust routes, speed, working patterns, seating or training, then compare later voyages to confirm whether the controls reduced exposure.

Above the action value, introduce proportionate controls and monitor their effectiveness. If above the exposure limit, immediate action must be taken, followed by further assessment.