Ferry terminals are usually seen as the bridge between land and water; an intermediate space where people gather and queue to hop from solid ground to a ferry or boat that will take them to elsewhere.

Hobart’s new ferry terminal, however, is both a building and a boat. Designed by Circa Morris Nunn, the Brooke St Pier is an 80 metre long, 20 metre wide concrete pontoon featuring three floors of “lightweight superstructure” that isn’t connected to land. Instead, the 4,300 tonne structure floats on water, rising and falling with the tide, and anchored to the seabed with triangulated stretching ‘bungee’ cables that modify their thrust angles with the changing water levels.

“By building a four metre deep floating concrete pontoon instead of hundreds of piers, considerable economies could be made over a traditional wharf, quite apart from creating a useful basement,” the architects note.

“This project is the purest expression of a wide-ranging collaboration between architects, engineers, builders and extremely passionate clients/operators,” they add in their competition entry. “Brooke St is a significant step in the ongoing transformation of the old port facilities into an active urban civic precinct, marking the beginning of a new chapter in the evolving life of Hobart’s waterfront.”

One of the contenders for the 2015 Tasmania Architecture Awards, this boat-pier is completely self-sufficient, carrying on board all the services and systems it requires to be habitable for users. This includes hydronic heating and cooling systems, which tap into the relatively temperature-constant water – about 12 degrees all year round – so that the structure essentially “floats on concrete and runs on water”.

This ‘Antipodean Brighton pier’ is also the ultimate in terms of recycling possibilities

At the same time, every opportunity was taken to reduce electrical demand, such as keeping light fittings limited to low energy options. The pontoons also collect rainwater for reuse, as well as to top up the ballast system.

While the nanogel-filled polycarbonate external skin which clads the pier is a stand-out element, letting daylight into the upper levels, insulating walls and roofs, and lighting up at night, Circa Morris Nunn points out that the biggest single unusual aspect is the pier’s ability to be towed away for use in another location if it is ever made redundant.

“The concrete pontoon has a design life of 100 years and if required repairs can be far more easily carried out than would be otherwise required to attack the foundations of a traditional building,” they explain.

Also of importance for the design team was creating a community dimension. This was achieved by dedicating a whole floor to a large local produce and product market, with two informal cafes, an up-market bar and offices. The boarding level can also double up as a function space for up to 1,200 people when it is not in use for ferry passengers and staff. These multifaceted uses are expected to inject vitality to the building and boat throughout the day, across all seasons.

Brooke St Pier is in the running for the 2015 Tasmanian Architecture Awards under the Urban Design, Public Architecture and Colorbond Award for Steel Architecture categories. Photography by Matt Samsom, Martin Schmidt and Nick Molle