Home' Ausmarine : Jan 2010 Contents The 8.5-metre Naiad hull is becoming
one of Kirby Marine's most popular
models, as users of smaller Naiads
experience the capabilities of the design,
wish to extend their roles, and look for
more size to achieve that.
Kirby's latest 8.5 is for the Marine Parks
division of the Western Australian
Department of Environment and
Conservation, primarily to operate in and
near the Ningaloo Reef on the upper west
coast. The RIB style is ideal for the many
encounters the vessel will have with leisure
craft, and its open sea abilities are needed
for travel outside the reef. Ningaloo is a
fringing reef, and covering distance
quickly is better done outside where
conditions are often blustery.
The vessel's layout is tropical style; with
a fabric canopy covering the entire cockpit,
and no impedance to air flow over the
windscreen. This choice of structure also
usefully reduced the boat's trailing weight.
There is a small cabin ahead of the driving
position whose use is entirely storage.
Carpeted shelves with fiddle rails are
capable of housing the likes of a portable
fridge and diving equipment.
Unlike the current preference in Police
and Sea Rescue 8.5s, the vessel has a small
well ahead of the cabin reached via a
watertight door, boarding other vessels
over the bow being the simplest method.
Although it is unlikely to operate in the
extreme conditions Police and Rescue
regard as routine, Kirby took precautions
against the accidental flooding of the well.
They doubled the freeing ports, and
enlarged the thumbnails over the ports to
encourage water flow.
Flooding of the well in earlier Police and
Rescue Naiads had never endangered
stability, but it did temporarily reduce
manoeuvrability -- a property usually in
high demand in the conditions causing
flooding: typically in breakers.
Like all Kirby Marine vessels, the hull is
constructed in aluminium. And also like all
other Kirbys, to specifications well in excess
of the USL Code, with all voids foam-filled.
The bottom has the usual steep deadrise of
27 degrees, but does not have the two steps
of some 8.5s. The buoyant tubes have seven
independent air chambers, and are heavily
reinforced at the wear points along the sides,
and on top where they are walked on.
Motors are a pair of 149kW Yamaha
four-stroke outboards -- a shade smaller
than the typical 8.5, reflecting the
generally lower urgency of its role.
Everything is comparative, of course, and
top speed is still 45 knots. Cruising at 30
knots, range is over 200nm.
Like all government vessels, the 8.5 is
almost extravagantly provided with radios;
there are no less than six aerials, servicing
private frequencies as well as 27MHz, UHF,
VHF and HF. The electronics package is by
Raymarine using a wide C120 screen.
Driving control layout has received a lot of
attention in recent Kirbys, with the intent
of reducing fatigue on long working days.
The coxswain has the minimum of
electronics in front of him, and the relative
positions of seat, footrest, throttles and
wheel are tuned to within millimetres.
A pair of suspension seats faces the
console, and a folding bench at the transom
provides casual seating for another four.
The entire cockpit is carpeted, over Kirby's
trademark shock-absorbing membrane.
Diving operations figure largely in the
vessel's future, checking moorings among
other tasks. The standard transom boarding
ladder, which the vessel has, puts a
boarding diver out of the coxswain's direct
sight as well as adjacent to the propellers.
To mitigate this, a second ladder is
mounted to port, folding up against the
For further information contact:
Kirby Marine Fabrication, Western Australia.
PH: (08) 9410 2270,
FX: (08) 9410 2280,
Type of vessel:
In survey to:
RIB patrol boat
Exmouth, Western Australia
Department of Environment
DEC Exmouth, Marine Parks
Naiad Design, New Zealand
Kirby Marine Fabrication,
2 x Yamaha outboards,
Beta Marine Windows
AUSMARINE January 2010 25
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