Underwater sea creatures are not usually a feature of the New Zealand Boat Show, but this year one exhibit is departing from the usual surface dwelling crafts to prove there is excitement below the surface, too.
A human-powered submarine built by University of Auckland staff and students will be on display before it heads to Europe to race against other underwater craft.
Shaped like a 3m long shark with a black body, red fins and fierce teeth decals, the Taniwha is the invention of Associate Professor Iain Anderson and his biometics students.
"It's been an incredibly steep learning curve," said Dr Anderson. "Every single thing that we have tried to do there is something we don't know or have to find some expertise for."
The impressive craft is not watertight, meaning its pilot is completely submerged in water and breathes oxygen through scuba equipment while he pedals the Taniwha.
The pedals operate fins that propel it through the water for the 100m race.
"Quite a lot goes into it, you have to make sure it is efficient going through water, have an air supply for the driver, buoyancy, control and all the while propelling it forward."
Dr Anderson said the invention used US Navy research as well as local technology and has taken hours of labour nearly every day since September.
"It's been excruciating and scary and we have had more challenges than you can imagine. I thought it was going to be a bit of a lark but it's turned into a serious engineering pursuit to make this thing work."
Despite the months of work, there are still some flaws to be ironed out before the European International Submarine Race in Bournemouth, UK in July.
Students Ryan Chao, Ben Pocock and Antoni Harvez will accompany Dr Anderson to race in the 5.5m deep pool, where they will compete against 11 other teams from around the world in time trial and slalom events.
The fastest speed on record for any person-powered sub was less than 4m a second, said Dr Anderson.
The Taniwha will be on display until the boat show closes at 6pm tomorrow and Dr Anderson and his students will be there to talk about and demonstrate its features.
• The Hutchwilco New Zealand Boat Show at ASB Showgrounds, Greenlane West, runs from 10am until 6pm today and tomorrow.