Despite a larger footprint Hackett says it offers "Ultimate's legendary off-road performance" thanks to a 440mm ground clearance, 24 degrees departure angle and 154 degrees ramp over angle.
Riding on a modified Vehicle Components' Cruismaster independent coil suspension with adjustable Koni shocks, he claims "it's going to eat up all the corrugations you can throw at it".
Ultimate engaged naval architects and composite engineers in the construction of the aerodynamic, monocoque (single shell) structure. The stone-damage resistant, moulded composite underbody is "engineered like a boat hull" and like the upper body is streamlined for "less air resistance".
Hackett said the Nautilus is being subjected to an industry-first automotive-style testing process, which includes testing the suspension components for tens of thousands of kilometres in the Outback.
"We have also engaged ACART (Advanced Centre for Automotive Research and Testing at Ford's Proving Ground) to test our hard connection points between the drawbar and the swing arms, into our composite chassis, for up to two lifetimes of rigorous offroad testing. A lifetime of testing we consider to be up to 100,000km of which 30,000 is in the dirt," he explains.
The Nautilus prototype on display at the Sydney Supershow was fitted with an OzHitch off-road coupling, and featured a large storage pod up front which incorporated internal compartments for the 100aH deep cycle battery and 12V/240V electrical system.
Externally, it has storage space for up to two gas bottles, jerry cans, a shower hose and slide-out cooktop.
The interior continues the nautical theme with white glossy walls and cabinetry and marine-synthetic teak floor.
An aircraft-style hatch drops down to provide staircase access, while another internal door folds away when not in use.
The electric pop-top roof raises in 20 seconds, while the rear queen-sized bed 'pod' slides out manually from inside.The single lounge comes with a detachable dining table, while the small kitchen features a three-burner hotplate, oven/grill, 150 three-way fridge, and sink with mixer tap.
Other standard features include a number of storage drawers, seven LED lights, a Fusion 600 Series iPod audio system, gas/electric hot water and Fiamma awning.
The optional ensuite features a shower, sink, and toilet, and includes solid privacy walls that fold away when travelling.
Two water tanks offer 180 litres in total plus there's a 20 litre grey tank. A roof-mounted rainwater harvesting system can also top up your supplies if required.