September 2023: Rubber expansion joints

This safety update is for operators of domestic and international commercial vessels using rubber expansion joints within a vessel’s safety-critical system.

Background

In early 2023 the Interislander ferry Kaitaki was travelling between Picton and Wellington with 800 passengers on board when it lost all power and drifted towards Wellington’s rocky south coast. A mayday was sent and passengers were ordered to put on lifejackets and await further instructions. After about an hour, crew were able to restart the engines and the vessel, escorted by tugs, returned under its own power to Wellington.

 

Investigation

A rubber expansion joint (REJ) is a flexible connector in a rigid piping system that helps to absorb noise, shock, vibration, physical and thermal energy.

Over time, the rubber component of an REJ hardens and becomes more susceptible to cracking and delamination (fracturing into layers). The rubber may also deteriorate and become softer or ‘gummy’.

REJ1
Image courtesy of TAIC
The ruptured rubber expansion joint (REJ).
REJ2
Maritime New Zealand
An REJ installed as part of a pipework system.

A preliminary investigation by the Transport Accident Investigation Commission (TAIC) found that an REJ which was part of the vessel’s high-temperature (HT) cooling water system ruptured, causing the loss of most of the vessel’s HT cooling water. This led to the four main engines and two auxiliary engines becoming inoperable and the vessel losing propulsion.

The TAIC investigation found that the REJ which failed had been installed when it was about 13 years old, had been in service for about a further five years, and it was about 18 years since it was manufactured. The ferry’s planned maintenance system showed that the ruptured REJ was due for replacement about two months before its failure.

 

Safety reminder

All vessel operators using REJs within a vessel’s safety-critical system should take into account:

  • the date of manufacture of REJs
  • their time in service, and
  • include REJs in maintenance schedules to ensure they are fit for purpose.

All vessel operators are asked to also take note of the following:

  • REJs are prone to degradation over time which can lead to defects including cracking, delamination and eventual failure.
  • If rupture of an REJ occurs it may impact the affected system rapidly and without warning, resulting in significant consequences to ship’s engine and equipment.
  • If REJs are used as part of a vessel’s safety-critical system, vessel operators should take into account all manufacturer requirements. For example:
    • REJs should be stored in accordance with the manufacturer’s recommendations.
    • REJs should be installed in accordance with the manufacturer’s recommendations.
    • REJs should not be kept in service longer than the manufacturer’s recommendations.
  • There are a number of different manufacturers of REJs. Vessel operators should be sure to follow the relevant manufacturer’s recommendations for storage, installation and time in service.
  • Vessel operators should ensure that maintenance and replacement of REJs is included in the vessel’s planned maintenance system.

 

Contact us for more help

If you have any questions about this safety update, please contact our Wellington office.

Phone:

New Zealand (toll free):
0508 225 522

Calling from outside New Zealand:
+64 4 473 0111

Email:

enquiries@maritimenz.govt.nz
Tell us what you need help with and remember to include your contact details (email address and phone numbers).