Completing one of the world’s first six-point crane release under water

After the 230 metre-long, 30m wide dredge Fairway, widened, lengthened and deepened Lyttelton Harbour’s navigation channel – an ambitious and untested plan was put forth to install new navigation aids.

Smith Crane & Construction’s Piling Manager, Matt Draper, successfully tendered the project to install several spar buoys along the channel without the use of divers – as is the usual practice.

Improving maritime safety, a spar buoy is a tall, thin buoy that is anchored to the sea floor via a concrete mooring block and chain – allowing it to float upright in the water.

This project’s buoys comprised a large platform on top where maintenance can be carried out on the various devices, such as solar  panels, light controls and radar reflectors.

Generally, installing spar buoys involves two winches – one to the lift the block and another to lift the buoy.

As they’re both lowered in the water, the buoyance of the structure straightens it.  Then a diver would disconnect the lifting points underwater.

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