Boulders vs boat ramp vs biosecurity

Department of Conservation —  09/11/2022

How to replace a boat ramp on one of the country’s most precious islands

This is a story about revamping a boat ramp. Sure, we appreciate it doesn’t sound like a story that will float most peoples’ boat, but what if we told you it involves more than 100 helicopter trips, dodging boulders, hard-working conservation dogs, and one very special island?

Te Hauturu-o-Toi/Little Barrier Island is a nature reserve in the Hauraki Gulf Marine Park/Ko te Pātaka kai o Tīkapa, administered by us through a joint conservation management plan with Ngāti Manuhiri. With one of the most unmodified forests left in Aotearoa, it provides a safe haven for rare and threatened native species. As such, it is closed to the public and a permit is required to access it. But access isn’t easy as the coastline is mostly comprised of boulders, some the size of a car bonnet, and they are continuously moving in the rough sea conditions of the outer Gulf.

📷: Looking from ‘West Landing’ to Mt Herekohu on Te Hauturu-o-Toi/Little Barrier Island on a stormy day

The only way to get big and heavy things onto the island is via the Hinemoana II, a 5.99m boat, by steering it through said boulders, onto a cradle attached to the rails of the boat ramp. It’s then winched 60 metres to the boat shed. No matter which way the wind is blowing it’s a difficult manoeuvre, and DOC Ranger Richard Walle studies seven different weather and marine forecasts, watching the sea conditions closely, before he deems it safe enough to land. Even then, conditions can change at the last minute and on departure or arrival Richard might need to push boulders off the ramp, dumped there by waves.

It’s therefore not an exaggeration to say the Hinemoana II and its ramp are a lifeline for the island, enabling all the important work that takes place on Hauturu by various iwi, our rangers and the Hauturu Supporters Trust.

A revamp has been on the cards for a while and quickly became urgent on inspection by divers who found holes in the underwater section (between tides) of the I beam, caused by the moving boulders. Works Officer Nick Fowler expedited the job but even so, it took a year due to strict biosecurity requirements, negotiations between the various stakeholders, and the logistics of shipping tons of concrete mix, rails, a digger and various other implements.

Top of mind was ensuring no pests or pathogens found a way to the island via the contractors. Biosecurity risks were identified by Island Biosecurity Advisor Claire Warren and Biodiversity Ranger Jenny Heath, while Conservation Dog handlers Adeline Bosman and Colin Christie organised visits to the sources of the material and equipment, through to loading them onto the two barges and helicopter. Meanwhile, cleaning the digger and equipment entailed a pressure hose on the outside, steam clean, and bug bomb in the cab of the machines.

📷: Conservation Dog handler Adeline with her Argentine ant detection dog, Vito, in the foreground, with handler Hannah Irwin and her plague skink detection dog, Harper, in the background inspecting the site of one of the sources of material.

On arrival to the island, a Skyworks helicopter undertook more than 100 trips to unload everything except the digger (which had to drive off the barge itself, getting wet in the sea… eat your heart out Little Yellow Digger!). The company has a Pest Free Warrant, now a requirement under the Auckland Regional Pest Management Plan for all operators on the Gulf.

📷: The Skywork helicopter unloads bagged concrete on pallets while Brett from CLL and Skywork ground crew work in the foreground.

The refreshed boat ramp features new rails with extra support in the form of concrete piles and blocks, as well as clips on the underside of the cradle to secure it on the rails. The angle of the boat ramp has also dropped slightly, and the floor of the boat shed dropped by 400mm to allow the gantry to more efficiently lift freight off the boat. All this effectively means increased safety getting people and freight on and off the island for the next 15-20 years.

📷: Contractors CCL Constructing Contracting place the foundation block.

Meanwhile, October is a super busy time on Hauturu, hosting a kākāpō team of four, three weed contractors and three contractors doing the ramp repair work. The upside is lively weekly potluck dinners, and Richard has been keeping momentum up by baking cakes.

This epic undertaking has run very smoothly thanks to our team and the main contractors CCL Constructing Contracting. Ka rawe tima!

One response to Boulders vs boat ramp vs biosecurity


    Great job people, as an ex-member of the Hauraki Gulf forum I understand how fragile the ecosystem is. Keep up the great work, thank you, Paul W Cronin.