MEDIA RELEASE

Date: 23 March, 2011

$20,000-Plus Upgrade For Kaipara’s Buoys, Beacons

Strong tides, shifting sandbanks and drifting logs and trees are among challenges facing local authority staff carrying out more than $20,000 of upgrades and maintenance on Kaipara Harbour’s buoys and beacons.

The Northland Regional Council’s 16.4 metre workboat ‘Waikare’ travelled from its Opua base to a temporary berth at Te Kopuru Boating Club recently for several weeks’ of work on the harbour.

Council Regional Harbourmaster Jim Lyle says the council carries out work at 15 of Northland’s main harbours over a rotating six-year maintenance schedule, which had last seen staff visit the Kaipara Harbour in 2005/2006.

The Northern Kaipara had a major upgrade at that time, which saw a number of new lit buoys and beacons installed. It’s currently home to several dozen ‘aids to navigation’ maintained by the council.

“This latest visit will build on those achievements and will include the installation of several new buoys in areas with some of the harbour’s strongest currents, as well as a new five mile LED light at Pouto Point.” Mr Lyle says.

“We’ll be carrying out a range of waterblasting, painting, mooring line and battery replacement and other maintenance and also plan to investigate reports of an uncharted rock in the Hargreaves Basin, right on the border of the regional council’s southern boundary.”

Mr Lyle says the Kaipara is one of the Southern Hemisphere’s largest harbours and poses its own set of challenges to the Waikare’s three crew due to its size, the tide and wave conditions found there and its relative remoteness. That was part of the reason the council was relying on – and very grateful for - expert local knowledge from several of its harbour wardens.

“The geography of the harbour is characterised by a number of channels which move constantly and shift sandbanks around. This in turn poses problems for fixed beacons as they can be left incorrectly positioned as those channels and banks shift.”

He says the Wairoa River also carries large numbers of logs and trees into the harbour.

“Coupled with the strong currents in the area, these destroyed or damaged most beacons previously installed at the top of the harbour.”

Mr Lyle says in recent years the NRC has successfully trialled large, custom-made plastic buoys manufactured by Ruawai-based Portstar Plastics.

“These buoys are highly visible to both recreational and commercial vessels using the harbour and are easily relocatable when channels and banks shift. They’re also environmentally-friendly and typically need only a waterblast and replacement mooring lines during servicing.”

Mr Lyle says introduction of lightweight LED navigation lights in recent years makes them ideal for use on the plastic buoys.

“The only real problem we’ve encountered in the last few years has been the force of the currents tilting the buoys, which rendered the lights less effective at night.”

He says the regional council, its local harbour wardens and the buoys’ manufacturer have worked together to overcome the problem.

“Portstar custom-builds the buoys to our requirements and they’re then ‘fine tuned’ by the maritime team with radar reflectors, lights, counterweights, mooring lines and mooring blocks.”

He says the buoy’s design has been modified for the high speed currents in the area and the first improved version has now been installed and seems to be performing well. In total, four new buoys – collectively worth about $10,000 - will be deployed where existing buoys are in the strongest currents.

Mr Lyle says any navigation aids which the Waikare cannot access will be serviced by another, smaller NRC vessel, ‘Gemini II’.

Weather-permitting, the Waikare is expected to spend about four weeks on the west coast before moving on to the Hokianga Harbour next month.

ENDS

© Scoop Media