December 2022: Walkie wheels aboard fishing vessels

This insight highlights issues about the risks for crew using deck machinery on fishing vessels.

This investigation insight is for

  • New Zealand commercial operators
  • Fishing skippers and crew
  • Maritime NZ maritime officers, investigators and technical advisors.



On Monday 2 August 2021, a mussel harvester vessel was conducting line preparation work on mussel lines in Forsyth Bay, Marlborough Sounds.

At approximately 1950hrs a crew member got his arm caught in a piece of deck machinery namely the Walking Wheels (walkie wheels) while working on the vessel.

He was pulled into the walkie wheels while attempting to reach a piece of rope lashing during line preparation for mussel seeding.

The crew member suffered severe injuries to his left arm, including three fractures and nerve damage.

Due to the severity of the injuries, a rescue helicopter was called and the crew member was air lifted off the vessel at approximately 2100hrs and transferred to Wellington Hospital where he received immediate treatment for his injuries.

Maritime NZ was advised of the incident via a S31 notice on 3 August 2021.


Scene information

The location where the incident occurred was Forsyth Bay In the outer Pelorus Sound. The location is approximately 28nm from Havelock.

The skipper recorded the conditions as being sunny with a light 0-10 knot northerly breeze blowing.

In the vessel logbook, sea conditions were described as great.

Walkie Wheels 1
Maritime New Zealand
Walkie wheels aboard the vessel before safety modification
Walkie Wheels 2
Maritime New Zealand
Walkie wheel with trip bar added to automatically shut down the wheel


Findings and action

  • While the injuries suffered by the crew member on board the vessel are severe and have undoubtedly affected the person’s physical and mental wellbeing, the risk of harm was never identified by the operator themselves or by three independent safety audits conducted prior to the incident.
  • The inductions and training completed by the injured party in the year prior to the accident are very thorough and encompass all of the typical tasks performed on board mussel harvesters.
  • There are clear warnings around keeping hands clear of the walkie wheels in the Standard Task Sheet (SOP) for the walkie wheels.
  • The conduct was accidental. In trying to reach for a lashing on the main line the injured party momentarily got too close to the walkie wheels and became entrapped. The operator had tried to ensure the safety of the workers by conducting thorough inductions and training of new staff especially around hazardous machinery.
  • It was evident that the crew were very safety conscious and because of their calm heads and quick thinking at the time of the accident, a more serious injury was avoided.
  • The operator has shown a commitment to improving the safety on the vessel post-accident especially with regards to the walkie wheels.
  • Maritime NZ considered all options by way of outcome but due to the systems already in place, as well as safety improvements by the operator post event, no further action was considered by Maritime NZ.
  • This incident should act as a catalyst for awareness on the dangers of unguarded walkie wheels. Potentially serious injuries can be sustained if a worker is caught in walkie wheels.
  • Controls that have been put in place by this operator include:
    • Painting the area around the walkie wheel to indicate to workers they should not enter;
    • Creating a document which sets out the correct PPE to wear around the walkie wheel, safe operating speed limit of the walkie wheel and the minimum safe distance to the walkie wheel;
    • A trip bar has been designed to automatically shut down the walkie wheel to prevent entanglement if it comes into contact with anything;
    • The emergency stops around the vessel were reconfigured to stop power to the hydraulic pumps instead of shutting down the engine. This allows crew to immediately stop all machinery in an emergency while ensuring all lights remain on. Mussel harvesters often work before daybreak and after sunset.
  • Operators should take appropriate and reasonable steps to mitigate the safety risks that have been identified as a result of this incident.