Mahurangi Coastal Trail taking shapely
Most of the Mahurangi Coastal Trail is already in use, and has been for decades. This, thanks to the entire coastline from Waiwera to the Mahurangi Harbour becoming regional park, by 1973. Within that time, built by park staff and student-labour grunt, a cliff-edge trail was created around Maungātauhoro—the prominent, 130-metre bluff between the Waiwera and Pūhoi rivermouths, immediately inshore of Mahurangi Island.
The Pūhoi River always presented the major challenge to linking the regional parkland northward from Wenderholm—the first, £186 800or $31.3 million, if converted by the Reserve Bank of New Zealand’s inflation calculator using the Housing category purchase, in 1965. At its rivermouth, the Pūhoi is two metres deep even at low tide, and can flow at more than three knots. A footbridge built at that point, however, would be visually very conspicuous, given the need to clear lofty yacht masts. The next practicable crossing point, 1.5 kilometres upstream, is almost 160 metres wider, and although the estuary there can be waded knee-deep at dead low tide, if recommended as part of the coastal walkway, the avenue for misadventure is conspicuous.
A design for an aesthetically acceptable footbridge, complete with opening span for vessels bound farther upstream, was commissioned. But even with the adoption of a, potentially pricey, appropriately serpentine form, by no stretch could it be claimed that imposition of the structure would improve the untouched aesthetic of the Pūhoi Estuary. Fortunately for the coastal trail’s prospects, Auckland Council’s parks planner courageously proffered that an alternative, a chain ferry:
…could become a unique attraction in itself without the need for large infrastructure crossing the river.
Since embracing that suggestion, concepts of craft at two extremes of sophistication have been worked up by experienced boat designers. The first, all-high-tech-composite, all-solar-photovoltaic, all singing and dancing, came with a price tag, inclusive of shore infrastructure—but not of gstgoods and services tax, of 15%—of $2 million. The other, plan-b, consciously crude plywood box would have barely spoiled $10 000, but it was designed under the designer’s misconception that a craft less than seven metres in length would not require to be built to marine survey. Then, consideration of the possible utility of being able to contribute to the Mahurangi green-lipped mussel reef restoration research project caused a rethink—the oyster barges hired for the deposition of mature mussels carry a cargo of six tonnes. The result is New Zealand-scow and Mahurangi oyster barge derivative, with the drawing-board title of Mahu.
Mahu, in its sense of gentle, particularly on the senses, is the design imperative. The Pūhoi Rivermouth is, it could be argued, the landscape epicentre of the Wenderholm Regional Park. The ardent hope is that park visitors happening for the first time upon the ferry in operation will have perceive it has having always been there.
Gentle, is also the impact the craft needs to have on the maurilife force, vital essence of the Pūhoi River, and for entirely pragmatic reasons. For river current to provide the zero-carbon energy to propel the craft from one bank to the other, the underbody needs to be free of the sharp, drag-inducing corners, or chines, characteristic of most New Zealand scows built. Serendipitously, a soft or rounded chine is also considerably gentler on the overly enthusiastic, young or old, who might approach the craft too closely when she is beaching to embark or disembark passengers. The hard, square chines of barges can scrunch downward with literally tonnes of foot-crushing force.
At slack water, when a four-stroke outboard motor is moving the ferry, those same gentle curves will keep petrol consumption to a minimum. Time, and experimentation, will also tell how often sail may reduce that consumption even further, and whether battery power is environmentally superior, given that the craft must be also capable of performing dawn to midnight regatta day service.
Proceeding by way of a redeployable or disposable prototype was amongst the initial criteria of the rivermouth ferry. Despite there being hundreds of cable ferries operating worldwide, including reaction ferries, no example of a reaction ferry operating in a tidal rivermouth have yet to be found. On the face of it, this might suggest that the safer option is to stick with the straight-forward cable-winched configurations that typically operate in such environments. But the conservative option is not always the best one. In this case, the main driver for embracing the reaction ferry principal is not its noble zero-carbon credentials but its lack of shoreward cables that could, all-too conceivably, pin a beach user’s foot or leg, hand or arm.
The factor underpinning the opportunity to affordably prototype the rivermouth ferry is that the craft will earn its keep elsewhere, and aside from any potential mussel-reef restoration work, such as ferrying members of its owner, Mahurangi Action, back and forth on regatta day, from sun up to midnight. Otherwise, a reasonably good case might be made for a battery power, if slack-water rivermouth ferry operation was the only need for propulsion. But by meticulously recording outboard fuel consumption, in exacting, real-world operating conditions, it will be possible to more soberly assess the practicality of deploying battery power—no favours are done responding to the existential imperative to rapidly move beyond fossil fuels by giving the immaculate misconception that everything that needs to move can be practicably moved by battery power. This is why viable electric buses are directly grid-powered, rather than battery-powered, and why Auckland, so far, has only two electric buses in operation, of a diesel-powered fleet of 1300.
Great Lakes scows, which inspired the New Zealand scow—two only were built in the Mahurangi: Lady of the Lake and Lake St Clair—were square-bowed, in typical athwartships-planked barge fashion, as was the first built in Aotearoa. It was soon found, however, that giving the scow a pointy end was well worth the complication and extra building time, to make the craft more easily driven into the seas encountered in the Hauraki Gulf. Serendipitously, the chevron-shaped New Zealand-scow bow lends itself to replication in the form of twin, angled bow ramps are perfectly suited for embarking and disembarking passengers while the craft lies at an angle to the shore. Angled berthing is dictated by the aforementioned up-to-3.3-knot current3.3 knots, or 6.1 kilometres per hours, which about 60% faster that iron-man swimming pace, which would otherwise work to swing the stern of craft parallel to shore, where the vessel would be too prone to becoming stranded by the weight of boarding passengers, or a falling tide, or both.
Neither oyster barges nor scows, traditionally, sported wheelhouses, nor did the high-tech. design proffered. But short of some ridiculously extravagant philanthropist pushing millions at the Mahurangi Coastal Trail, or mayoral candidates less shamelessly pro-car populist, the only way this public good ferry can be operated is with volunteer crew. And while there will be no shortage of such volunteers for skippering and crewing the craft, contributing to their prospects of kidney failure by failing to have comfortable quarters, when working long and otherwise richly rewarding watches, for brewing and consuming beverages, and for subsequent bladder relief, would be unconscionable. The challenge then becomes to design that superstructure that it completes, rather than spoils, the vessel’s aesthetic. The distinction between a straw hat and a Panama.
Of course, the feather in the cap, or Panama, is the signal mast, which in addition to port, starboard, stern and masthead and deck lights, leds would indicate direction-of travel across its yard, forward- and stern-facing. Until it has been operating there for decades, the last thing most skippers navigating the Pūhoi Rivermouth will expect to encounter is a craft operating across the channel. Every reasonable measure needs to be taken to alert skippers preoccupied with piloting their craft in or out of the estuary of the ferry’s presence and activity. This will include flying signal flags from the same mast, such as s-for-Sierra, to indicate ‘I am operating astern propulsion’ when backing off the beach.
While proponents of the Mahurangi Coastal Trail have not the slightest doubt that, if they build it, droves of walkers will come, it is still more sound to trial the Pūhoi Rivermouth ferry operation, both to gauge that response, but also to evolve a safe and manageable style of operation. Initially, the ferry will be trialled without passengers, until the choreography of the craft, swinging across the current, then gracefully berthing—without the potential to pitch people who may missed the message and stood up too previously, forward on their faces. When the craft is ready to ferry its first passengers across the Pūhoi, it is possible that they be strictly financial members of Mahurangi Action Incorporated, the vessel’s owner. In any event, to service will be not be for hire or reward, which utterly includes kohate reo Māori: gift, present, offering, donation, contribution. Long-term, it may be determined that it is desirable to charge fares to generate income for cover maintenance and replacement cost of the craft, if not for paid crew. Current indications are that volunteering generally, but in particular for such a socially and environmentally rewarding pastime, is more than sufficiently popular for it never to be necessary to employ crew.
Jade River: A History of the Mahurangi was written, edited and published, mostly as a volunteer project. The interest it generated propelled Mahurangi Action’s membership to more than 300, but since, a combination of a lack of tangible incentives to subscribe and the move to paperless invoicing has drastically reduced the number who regularly renew as financial members, in any one year. It is probable that those who wish to avail themselves of the ferry will be more than happy to pay an annual, $10 individual or $20 family membership for the privilege, and to have a say in the society’s affairs to boot.
Coinciding precisely with the decision to proceed with a community-built prototype vessel, Auckland Council has employed a Pūhoi to Pākiri trails programme manager, Chris Charles. Chris’s impeccable credentials for the role include six years establishing and managing community and inter-government partnerships with the Department of Conservation, and project management at the International Institute for Sustainable Development, Switzerland, promoting sustainable transport options.
Implemented heedlessly, the Mahurangi Coastal Trail would reinforce car-dependency. Implemented thoughtfully, it could reduce it, including by connecting to the public transport terminus at Waiwera. The regional parks were conceived in the early years of the Master Transportation Plan for Metropolitan Auckland, 1955, which had utterly embraced the car and the motorway as the region’s future. Being able to throw a picnic blanket on the ground within a few paces of the car boot, and the beach, was the epitome of regional park bliss. Key to changing that mindset, half a century on, in respect to Mahurangi regional parkland, is to make public transport the premium option for reaching the Pūhoi Rivermouth ferry. If a volunteer-operated Waiwera–Wenderholm shuttle dropped trail users closer to the ferry than the car park, public transport would suddenly be the premium service.
The coastal trail, arguably, is also key to extending the interest of regional park visitors beyond the immediate and obvious appeal of Te Muri Beach. Because although the beach will always be the main drawcard—at least until sea-level rise succeeds in submerging most of the world’s—there are many attractions besides. One gem that the Mahurangi Coastal Trail could help put on the map involves continuing upstream 1.5 kilometres from where the route otherwise turns and abruptly climbs at a steeper-than-optimal gradient towards Te Muri Beach. At either ear of the head of a rarely visited bay there are abrupt rockfaces, dressed with waterfalls, surprisingly brutalist in the otherwise gently sculptured Mahurangi geomorphology. The trail, to the north, should protect the sensitive head of Te Muri Spit, in respect to both the dunes dotterel nesting sites and the urupā, nearby.
Whether the prototype scow will be launched in time to ferry volunteers during the next Mahurangi Regatta remains to be seen, but the earnest goal is to begin trialling the craft in Pūhoi Rivermouth reaction-ferry mode before the end of the 2019–2020 summer.
Scow-End of Era Two only, early, scows were built in the Mahurangi: the Lady of the Lake, by Rufus Dunning; and the Lake St Clair, by John Darrach. Although these pragmatic craft provided a lifeline for coastal vessels and their builders in the struggle for sail to compete with steam power, they conceivably helped hasten the end of Mahurangi ship building, in favour of bigger yards at Ōmaha and on the bustling Waitematā Harbour.