Please attribute to Interislander Executive General Manager Duncan Roy:
Following the decision to cancel the contract to build two larger ferries in February, which were scheduled to arrive in 2026, KiwiRail’s Board commissioned international maritime assessors Den Norske Veritas (DNV) to understand what is required to extend the life of the existing fleet.
DNV reported back this month and has found the existing fleet to be in a better state than thought previously and that it will be able to continue running reliably beyond 2026 with additional maintenance.
It found the three vessels have been well maintained. While the ferries are aging, it has concluded it is possible to keep the three vessels running at least until 2029.
The steel hulls are in particularly good condition. This is due to Interislander's approach of not sailing in very heavy seas. We do this to avoid discomfort to passengers and animals on board and it has resulted in the ships’ steel hulls being about a third of each vessel’s chronological age.
To keep the ferries delivering reliable services for customers, DNV has advised we will need increase our investment in ongoing maintenance and upgrade older, obsolete systems, as required.
The result of DNVs study is a very positive sign. We will need new ferries, but the assessor’s findings mean that we can continue delivering reliable services for passengers and our freight customers until new ferries are built and arrive.
Over the last few years we have made significant changes to fleet maintenance. This includes implementing detailed asset management plans, taking on specialist staff to provide greater maintenance assurance and taking the three ferries out of service more often for routine maintenance.
The changes we have already made have shown good results, with solid levels of service reliability over the last year and a half. We now need to go further.
In light of DNV’s new information we will be updating the ferries’ asset management plans, and seeking additional funding from KiwiRail’s Board to make sure our maintenance keeps the ferries running reliably as they get older.
We also expect each ferry may need to be out of service for longer in wet and dry docks to undertake this maintenance.
To ensure a high level of maintenance, Interislander is proposing to spend, on average, close to $36 million dollars each year between 2025 and 2029. It compares with an average of $29 million being spent on the three ships each year between 2019 and 2024. Maintenance funding will need to be approved by KiwiRail’s Board on an annual basis.
Interislander upgraded Aratere’s steering system during its May wet dock. Work was also undertaken upgrading Kaiarahi’s propulsion control and monitoring propulsion system during its wet dock that ended earlier this month.
An enhanced inspection and monitoring regime is already in place across other ships systems that are facing obsolescence.
We are working through what system upgrades will be required in the coming years, some of which are dependent on the Government’s decision about replacement ferries and when these are expected to arrive.
It’s a balancing act. Obsolete systems are operationally safe but are more difficult to repair if there are issues. Some equipment is no longer manufactured and replacing obsolete systems is a larger undertaking than maintenance, and will come at an additional cost.
Since February 2023, Interislander reliability has increased and remained at a high level in all but one month. In the most recent peak season, between December and April, it was at 99 per cent.
Changes the Interislander maintenance since 2023 include:
Further information can be found here