High potential near miss: tensioner pad dropped to under deck carousel

  • Safety Flash
  • Published on 3 December 2018
  • Generated on 13 February 2026
  • IMCA SF 26/18
  • 2 minute read

During the trans-spooling of an umbilical, a tensioner pad retaining bolt sheared, resulting in a 1.5kg tensioner pad dislodging and falling 11m to the under-deck carousel, where it struck the already trans-spooled umbilical.

What happened?

The dropped pad then bounced towards the starboard side, narrowly missing the deck supervisor, and landed on a salt sack approximately 1 metre from him.

20te Tr-Cat tensioner

What went wrong? What were the causes?

  • A decision had been taken not to change the grade 8.8 bolts with the 10.9 bolts, due to resources, timescale and difficulty of access.
  • The retaining bolt was not subject to an inspection, nor were the torque values checked due to the difficulty in accessing the tensioner.
  • Risk assessments had not been conducted prior to the work activity, therefore there had been no consideration of potential dropped objects or mitigation thereof.

What actions were taken? What lessons were learned?

  • Replace M10 x 25mm grade 8.8 retaining bolts with M10 x 25mm grade 10.9 on all equipment prior to mobilisation to vessels.
  • Corrective work orders to be fully completed inclusive of inspection of tensioner pad retaining bolts and torque value checks, prior to mobilising equipment to vessels.
  • Risk assessment of this type of work should take place before it starts.

Members may wish to refer to:

Latest Safety Flashes:

Dropped GRP cover during subsea lifting

A vessel was lifting and relocating a Pipe Line End Manifold (PLEM) GRP Top Cover when the load became detached and dropped approx. 7m.

Read more
Umbilical support frame made contact with passing vehicle on public road

Whilst travelling, a contractor transporting umbilical support frames (USFs) made contact with a passing vehicle as one of the frames dropped down.

Read more
Petrol driven equipment left stored in an emergency generator room

Stored snowblower created an unnecessary fire and explosion risk, as well as blocking access around critical equipment.

Read more
Mechanic got burns due to fire in portable generator

During refuelling, petrol (gasoline) spilled around generator and ignited.

Read more
Some positive findings and good practices

Collection of some positive findings and good practices.

Read more

IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of the entire offshore industry.

The effectiveness of the IMCA Safety Flash system depends on the industry sharing information and so avoiding repeat incidents. Incidents are classified according to IOGP's Life Saving Rules.

All information is anonymised or sanitised, as appropriate, and warnings for graphic content included where possible.

IMCA makes every effort to ensure both the accuracy and reliability of the information shared, but is not be liable for any guidance and/or recommendation and/or statement herein contained.

The information contained in this document does not fulfil or replace any individual's or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.

Share your safety incidents with IMCA online. Sign-up to receive Safety Flashes straight to your email.