Home' Work Boat World : September 2010 Contents The Fullers Devonport ferry 'Kea' is a familiar sight on the
Waitemata Harbour, ferrying passengers from Devonport to the
down town ferry terminal and back again. Built 21 years ago in
Whangarei, she is designed so that she does not have to be
turned around when berthing.
After she has berthed, the skipper simply moves from one end
of the bridge to the other and what was the bow of this double-
ended vessel becomes the stern, and what was the stern now
becomes the bow.
Because of this, the 'Kea' has always had two radars, one looking
When the previous radars were due for replacement vessel owner,
the Fullers Group, looked at all the options that were available. AIS
was also being looked at to make the 'Kea' more visible in the harbour
during low visibility and to meet harbour control requirements.
Radar performance is an important criteria with this vessel as on
weekends and public holidays the harbour becomes awash with
private craft of all types including kayaks and small inflatable boats
which are traditionally hard to detect on radar.
After a discussion with New Zealand Simrad distributers
Advance Trident, the new Simrad BR24 broadband radar was
chosen along with the Simrad NX45 30cm colour chartplotter
screen to display it on. This was incorporated with a black box AIS
transceiver, which will display other vessel AIS targets on the chart
plotter screens, and send the 'Kea's' AIS position to other traffic in
As before, two sets were used, with one 30cm screen at
either end of the bridge, and two BR24 radar scanners fitted
above the wheelhouse.
Instead of the 4kW radars that were on board previously, the
Simrad broadband radar uses a long swept pulse of very low power.
The peak power of the broadband radar is 0.1 watts, or ten percent
of the power of a cellphone.
This means that there is no possibility of harm to the public due
to high radiation levels. It also means that the many small targets
in the harbour won't get swamped in power.
By sending out a long, low-power, swept pulse, the return pulse
is compared with the transmitted pulse. The processing then rejects
the unwanted noise and displays only the targets. The nature of
the transmission means that targets very close together get
separated out instead of being painted as one large target.
The end result is an uncluttered display with closer target
detection and better target separation, which is most important on
a busy summer day on the Waitemata harbour.
The captain and crew on the 'Kea' have reported back that the
performance of the Simrad broadband radar is absolutely superb.
For further information contact:
Navico, New Zealand.
New navigation electronics for
Devonport seabus 'Kea'
The double-ended ferry 'Kea' was re-equipped with two Simrad BR24
broadband radar sets aong with two Simrad NX45 30cm colour chartplotter
screens, one in each bow
FOCUS ON NEW ZEALAND
WORK BOAT WORLD September 2010 43
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