The jetboat proved to be nifty in
the turns and a good seaboat
cargo on the large aft working deck. They each have a ���moon
pool���, and the prop boat had to have a bollard pull in excess of
6.5 ton for when in tow boat mode.
As commercial vessels, they had to comply with the NSCV
rule under the Western Australian survey authority, with the jet
boat operating under category 1B and 1C and the prop boat 2B.
To meet these standards the engine spaces are protected by an
onboard fire suppression system.
The 15m vessel is powered by twin Caterpillar C12 540hp
marine diesels coupled to conventional drives, while the 16m
vessel is water jet powered by twin Caterpillar 707hp���s driving
twin Hamilton HJ 364 water jets.
To meet the Australian survey standards Shipwright Agencies
were asked to supply all the Tides Marine ABS and Lloyds type
approved fittings for alloy boats, including Sure Seal shaft seals,
PTFE bearings, couplings and the rudder post bearings and seals
which eliminate metal to metal contact, abrasion, electrolysis,
and corrosion.
To achieve the required bollard pull the prop boat has two sets
of props: one for ���free running��� giving a top speed of 28 knots,
and the other for high pulling power that sacrifices top speed to
approximately 14 knots, but gives a bollard pull of 8.6 ton with a
12 Professional Skipper March/April 2013
towing speed of seven knots plus, depending on the tow.
The jet boat has a top speed with a reasonable load, of 30
knots, and is a metre longer than the prop boat with its transom
overhang protecting the Hamilton Jet units. Other than the length
difference, the boats are outwardly exactly the same.
Constructed in marine grade alloy plate, the construction design
had to be very robust to comply with scantling requirements for
the Australian coastal survey and the tough conditions they will
be working in. To this end, when looking through the voids, it
is easy to see where the added strength and welding has been
built in to the vessels. While in the voids, we note that there are
two large 1660lt fuel tanks of alloy construction, and two 300lt
potable water and a grey water tanks, as well as all the battery
boxes that are manufactured by Hercules Tanks Limited in noncorrosive polyethylene.
Essentially designed as day boats with the ability for limited
crew to overnight, or two to three-day trips, the accommodation
is minimal, with two large single berths down in the hulls that
are more of a rest area for when working long or extended shifts.
There is a comfortable dinette and small galley behind the main
conning position in the deckhouse, while outside off the aft deck,
is a small head and shower compartment.
