Leak in hot water system for saturation divers

  • Safety Flash
  • Published on 9 January 2024
  • Generated on 2 October 2026
  • IMCA SF 01/24
  • 1 minute read

Divers Hot Water Unit had a water leak.

What happened?

During saturation diving operations between bell runs it was noted that Divers Hot Water Unit #2 had a water leak. The leak was investigated and located, but was found to be in a place with very poor access. There was a small hole in a pipe, which on investigation was found to be a bigger hole under surface corrosion.

The Dive Supervisors and Dive Superintendent were immediately informed about the issue, and diving was suspended due to there being no backup for the remaining Hot Water #1 Unit.

What went wrong?

  • Due to very limited access, it was not possible to inspect the tank outlet of the 4″ closed circuit pipework.
  • External corrosion had over the years completely corroded the 4mm pipe in a very limited area.

What was the cause?

  • The direct cause: corrosion over many years.
  • The root cause: The inaccessible location [for visual inspection] of the pipe.
Leak in hot water system for saturation divers

The hole at 6 o’clock in the water intake

Leak in hot water system for saturation divers

Sleeve welded at the area of corrosion

Leak in hot water system for saturation divers

Location of the hole, inaccessible for visual inspection. Picture shows the back part of the unit mounted against a wall

Actions

  • Sleeve welded on the leaky area;
  • Hot Water Unit #1 was inspected and no defects found;
  • Consider wall thickness measurements of old pipes.

Latest Safety Flashes:

Hydraulic oil leak detected below moonpool

A hydraulic oil leak was identified below the moonpool after the worktable doors were opened.

Read more
Dropped scaffold board (kickplate) – SIF near miss

A scaffolding kickboard was accidentally dropped falling from a height of 6.5 metres to the main deck.

Read more
H₂S detected on deck

During vessel transit back to port, Hydrogen Sulphide (H₂S) was detected in the open space on the main deck.

Read more
Restoration and verification after maintenance

A missing flooring panel was identified beneath a 415V bow thruster electrical motor cabinet.

Read more
Vessel contact during materiel transfer in adverse weather

One vessel lost heading and position control because of the strong winds and swell, pushing it toward another.

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.