Hira resident Rudy Heeman, a mechanic who has spent the last 11 years building hovercraft in his spare time, has come up with a model that does more than skim the surface.

Over the past year, Mr Heeman has built a "wing in ground effect vehicle" - a hovercraft able to fly because of a peculiar set of aerodynamic principles.

He said the "hoverwing", which is almost complete, has drawn Atawhai Drive residents out of their houses and motorists out of their cars to watch test flights over the Haven.

While Mr Heeman has built and sold hovercraft before, he said the hoverwing gave him the kind of butterflies in his stomach the Wright Brothers must have felt.

After more than 800 hours of building time, he took it for its first flight just before Christmas last year.

But he refused to let his two daughters watch, just in case something went wrong.

He picked the Haven so his friends could accompany him in a "rescue boat", and because it was near the hospital.

That test flight ended in a crash landing, but a single bruise to his leg meant Mr Heeman knew exactly what adjustments he needed to make.

Now, the craft is only a few weeks away from completion.

Although the hoverwing will be able to carry a passenger, Mr Heeman has yet to decide who will be first to don the second life-jacket.

His family and friends have supported him through the building and testing process, but then there are also strangers such as the lady with three dogs who turned up at the Haven one day and said it should be her.

Mr Heeman said the project had cost tens of thousands of dollars and countless hours of his time.

He had built a new workshop, learnt how to become a fibreglass laminator and modified a Subaru car engine to power the vehicle.

The hoverwing was an extremely efficient method of transport, and Mr Heeman said the optimum height for it was about 1.5m above the water - he reached 98kmh on his last speed test.

Mr Heeman said he did not plan to sell the machine, but had learnt so much from the building process that he was keen to build another model.

"I've taught myself how to fly, and my hovercraft how to fly."

He would continue to test the vehicle over the Haven when the tide was in, so a rescue boat could accompany him and he did not disturb the bird life.

He only knew of one other person in the country building a wing in ground effect vehicle, but said many had been made in America and Russia.

Maritime New Zealand spokesman Ross Henderson said a wing in ground effect vehicle was considered to be a maritime craft and fell under maritime law.

Civil Aviation Authority spokesman Bill Sommer said the vehicle was not classed as an aircraft because it used an air cushion which relied on water.