Learning outcomes from a real time diver recovery

  • Safety Flash
  • Published on 2 June 2021
  • Generated on 24 July 2026
  • IMCA SF 15/21
  • 4 minute read

During a saturation diving operation a dive team became involved in the recovery of an incapacitated diver into their bell.

What happened?

Whilst diver recovery drills are practised frequently, this Safety Flash concentrates on the feedback and lessons learnt by the team during a real incident. 

The dive system had a bottom mating bell with a 6m vertical trunking going from the diving bell to the floor of the Entry Lock. In order to transfer a casualty a diver recovery hoist was used. The diver recovery hoist in the bell was to be used for both diver recovery and also to be used to transfer the incapacitated injured diver to the entry lock 6m below.

As this was a medical incident, the root causes are not relevant here.

What lessons were learnt?

Equipment:

  • Diver Recovery System – During the recovery of the incapacitated diver, it became apparent that due to the fact that the diver recovery lift was capable of reaching the bottom of the entry lock, not just the bell stage, it could have become difficult to manage the consequent large amounts of loose rope during the lift.  It was felt by the bell team that this had the potential to cause difficulties inside the bell for both deployment and use, especially when an incapacitated diver was recovered.  A proposal was made  for 2 x shorter diver recovery lifts in the bell sufficient to recover a diver from the stage into the bell and a second set of longer diver recovery lifts available at the moonpool and to be put in the trunking to allow for transfer of an incapacitated casualty from the bell to the entry lock.  This would significantly reduce the amount of loose rope within the bell during a diver recovery, as well as reduce the risk of entanglement. 
  • Chamber Medical Kit – On examination of the chamber medical kit it was found that the Pocket Mask had a gas-filled seal.  At depth the seal had compressed to the point of being useless.  A different bag valve mask was used, thus was not an issue, but it highlights the need to check the chamber medical kit and that the pocket mask has a silicon face seal is not a gas-filled faced seal type.

Procedures:

  • Use of Visual Observation – Close ROV observation of the diver allowed immediate recognition that “something was wrong”. The ROV picture clearly showed that there was an serious incident and not just a comms issue.  It is essential that a diver is monitored, either by ROV or remotely, when entering and exiting a bell during the hydrostatic change which occurs during this period.

Training:

  • Realistic Drills – The dive team considered themselves fit but were surprised at the effort involved during the rescue, which reinforces the need for good diver fitness. This brought the importance of “realistic drills” into focus and the dive team requested use of a weighted mannequin when conducting the following drills:

    • Recovery of the mannequin (150 kg) from the bell stage into the bell prior to blowdown.

    • Transfer of a mannequin (100 kg) from chamber to Self-propelled Hyperbaric lifeboat.

    • It is also important that all diving supervisors are routinely exercised in the management of a diving  emergencies.

Medical Personnel Involvement:

  • The vessel medic also felt that it is appropriate to be more involved in the diver drills to provide a better general understanding and a chance to observe and feedback as well as gain a better understanding of the capabilities and limitations of the divers’ medical skills.  In addition, it was felt that all divers going into sat would benefit from a brief CPR refresher to ensure that their skills were up to date.

Latest Safety Flashes:

MAIB: Catastrophic engine failure and subsequent fire

MAIB has published Accident Investigation Report 10/2026 into a catastrophic failure of a diesel generator engine on board the vessel Kommandor Susan.

Read more
BSEE: Compressed gas cylinder hazards

BSEE has published Safety Alert 516, relating to potential risks involving compressed gas cylinders.

Read more
MSF: dropped object inside vessel tank

MSF have published Safety Alert 26-05 relating to a tank cleaning machine coming lose and falling within a tank on a vessel.

Read more
Uncontrolled movement of cargo

During offshore cargo operations alongside a rig, a single pipe loaded on deck shifted due to vessel motion and swell conditions.

Read more
Positives – rubber seals on hatches, securing of shackle pins, fuel sample box

A Member reports a few positive findings.

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.