Damage to bulwarks during overboarding of mattresses

  • Safety Flash
  • Published on 4 July 2022
  • Generated on 14 July 2025
  • IMCA SF 16/22
  • 2 minute read

During a lifting operation, mattresses hit the port side bulwarks causing damage.

What happened

During the overboarding of a mattress stack (3x 150mm mattresses) using a mattress frame, the mattresses made contact with the port side bulwarks causing damage.  Before and during the lift, the weather conditions were suitable for the operation.

As the load was lifted outboard, a swell caused vessel motion which led to a pendulum effect on the mattresses. The mattresses then hit the port side bulwarks causing damage.  No-one was injured.

What was the cause?

The immediate cause of the damage was that the mattress stack made contact with the port side bulwarks during vessel motion due to swell as the load was overboarded. 

Subsea UK photo of mattress stack overboarding

image: Subsea UK

What was the cause?

The immediate cause of the damage was that the mattress stack made contact with the port side bulwarks during vessel motion due to swell as the load was overboarded. 

What went right?

The operation was conducted within defined parameters, all pre-lift planning activities were completed, tag lines for initial overboarding were used and safe personnel positioning was observed.

Actions

  • Further engagement with deck crews to discuss worksite, crane / task specific challenges or difficulties they face during lifting operations. A series of “Times out for safety” were used to:
    •  Present the scenario, explain that everything was done as it should have been.
    • Explain the challenges associated with the lift because of deck / crane design including crane speed and limitations.
    • Discuss anything the teams found challenging – with a view to proactive learning.
    • Record and share as appropriate any concerns, challenges or ideas to improve things.
  • Review lift plans and lift planning procedures to ensure prompts are provided to consider the limitations of the crane to be used including speed, line out, route for the lift etc.

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