The wavescreen and walkway replacement is one of the largest projects in the Long-Term Asset Management Plan (LTAMP). Here is why it is happening, who is doing the work and how each section is built.
Why it is being replaced
Shareholders commissioned the project at the 2019 Special General Meeting. A structural inspection that year found many key parts of the original cantilevered walkway and upper wavescreen in poor or very poor condition. The new walkway also sits 50 cm higher than the old one, to allow for sea level rise.
The project was first scoped as a like-for-like timber and steel replacement. It was redesigned to use vinyl, fibre-reinforced polymer (FRP) and steel, which have an expected service life of more than 50 years, compared with 25 to 30 years for treated timber in the same conditions.
Six phases
The full length of the wavescreen and walkway is being replaced in six phases. As of March 2026:
- Phase 1, Pier D to E: paused while the contractor focuses on Phase 2. Two more underpinning piles will be added to strengthen this area.
- Phase 2, Pier A to A/B: on schedule. Five bays complete, with FRP grating laid and the gangway to Pier A in place.
- Phase 3, Pier A/B to B: starts once Phases 1 and 2 are complete.
- Phases 4 to 6, Pier B through to Pier D: not yet started.
Who is doing the work
- Gary Teear, Offshore & Coastal Engineering Limited (OCEL): chartered marine engineer, providing engineering services for the project.
- Wayne Angus, Undersea Construction Limited (UCL): civil engineering and commercial diving company. UCL has maintained Chaffers Marina since 1993.
How each section is built
The work goes bay by bay. A bay is the distance between two steel columns, usually 3.6 to 4.0 metres, and each phase covers 8 to 10 bays.
- Strip out: remove the old timber wavescreen and walkway. Some of the wavescreen stays in place until the columns are ready to cut, to limit exposure to waves.
- Steelwork: cut the existing steel columns below the waterline, bolt on an extension, then bolt on the new cantilevered walkway beam.
- Piling: repair, sleeve and grout the underpinning piles that support the gangways and gates, and raise them by 50 cm to the new walkway level.
- Walers: measure, cut, weld and galvanise the three horizontal support channels off site. All 67 columns are at different spacings, so every set is custom-made.
- Walkway bearers: the same process for the walkway support channels, then lay cable trays ready to move the service cables from behind the wavescreen.
- Cladding and grating: attach vinyl sheet piling to the wavescreen and lay FRP grating on the walkway.
- Fit-out: install gangways, gates and handrails.
What slows the work down
- Tide and swell: work in the intertidal zone, such as drilling into existing steel, can only happen at low tide, and much of it is done from a floating pontoon that needs calm water.
- Custom fabrication: each bay’s steel is made to measure in a workshop in Lower Hutt.
- Live services: at Pier A the team has had to work around live 230 V power and data cables, not all of which can be moved.
- Unforeseen conditions: between Piers D and E, an unstable column needed a new reinforced concrete foundation, poured at a depth of 10 metres. We expect more issues like this as the work continues.