The band's about to strike up and ‘Tango' will be stepping out for her last dance.

‘Tango' – the oldest of Port of Tauranga's seven ship-to-shore gantry cranes – is being stood down, decommissioned. Her name will be erased from the dance cards.

Tango, as she is called, is the port's oldest crane and understood to be one of the oldest Liebherr gantry cranes operating anywhere in the world.

'The short answer is the crane has become obsolete,” says Port of Tauranga's property and infrastructure manager Dan Kneebone. 'Obsolete in the sense we are receiving bigger ships and with bigger ships you need bigger cranes to service them.” The new Liebherr cranes can lift two containers at a time – so twice as much and twice as fast.

While the traditional tango is a bit of hot and sensuous Argentinian exactness, Port of Tauranga's ‘Tango' is more a spindly wallflower sitting prominently at the front of the container terminal wharf – a gigantic praying mantis about to strike, or a giraffe perhaps.

She is prominent on the harbour city's skyline.

'And she's there because she's servicing the coastal feeders,” says Dan.

But cranes, like most things, have a design life. For a gantry crane it's in terms of the number of lifts. And Tango's is nearing an end. 'It's like your car,” says Dan. 'There are a lot of moving parts constantly being maintained and replaced. It gets to a stage where it's uneconomic to repair them because they are just too old.”

Sometimes the old cranes have an afterlife – they find new purpose elsewhere. 'They can but this one won't,” says Dan. 'It sounds horrible, it's going to get scrapped.” This lady has a history. Tango was initially commissioned on the Mount Maunganui Wharf 37 years ago in 1979 as a conventional crane. She was reincarnated in 1999 – barged across the harbour to Sulphur Point where she became a container crane.

Who knows how many containers she has hoisted ashore or aboard? 'A lot of container cranes are designed to do about two million lifts. Some of the new cranes are certified higher. But we just don't know with Tango.” And apparently there is someone one with a clipboard standing there checking them off? Well, kind of. 'The new cranes we could tell you exactly how many lifts, but Tango no.”

The old Liebherr gantry crane will know her time is nearly done. Two new cranes, which arrived in bits from Liebherr's Killarney factory in Ireland in August, are now being assembled behind her at the container terminal at Sulphur Point.

They are due to be operational later this month. So when the music dies in December, so will Tango. She will be dismantled, she will slowly disappear off Tauranga's skyline.

There are still port employees who were around when Tango was commissioned. They will swap stories at a function when she is decommissioned. Or will it be a wake?

Then the flash new-generation, two-at-a-time Liebherrs will step up for the Port of Tauranga.