Contractor Historical

Devonport’s Calliope Drydock – favored by fate

When it opened 130 years ago Devonport’s Calliope drydock was the largest in the Southern Hemisphere. Dug by hand in a little over three years, the project exemplified the era’s pioneering spirit, but perhaps its real fascination lies in the quirky coincidences that punctuate its history. Lawrence Schäffler reports.

Many would list the drydock near or at the top of New Zealand’s most challenging 19th century engineering projects. It was a remarkable accomplishment for a small, developing country in a lonely corner of the South Pacific.

When it was officially opened with great fanfare on 16 February 1888, two vessels were shoe-horned in to illustrate its cavernous capacity – the HMS Calliope and HMS Diamond. A common misconception (even today) is that the first of these ships gave the dock its name – and why not?

After all, she was a handsome 2770-ton, 235-foot hybrid corvette, the first of the Royal Navy’s new class of sail-and-steam vessels. In addition to her vast spread of canvas she was fitted with coal-fired boilers and a steam engine driving a single screw.

In reality, her presence at the opening ceremony was nothing more than an improbable coincidence. The dock was, in fact, named after the promontory from which it was carved – Calliope Point.

Curiously, though, Calliope Point was named after a ship – an earlier HMS Calliope. A Royal Navy frigate, she’d visited in 1845 so that her skipper – a Captain Owen Stanley – could survey the Waitemata harbour and chart and name its prominent landmarks.

There are further quirks. A calliope was a 19th century musical instrument which created tunes by forcing steam through an arrangement of whistles. Few survive today, but they were very popular on riverboats and in steam-driven carousels. Though unmusical, the drydock’s first pumps, too, were operated by steam-driven engines.

It could also be argued that fate played a friendly role in the project’s fundamental design and construction. Luckily for the Auckland Harbour Board (it commissioned the drydock), a British engineer supremely qualified for the job just happened to be in New Zealand at the time.

William Errington had immigrated to Australia in 1854 and became a mining engineer in Ballarat, designing and building large steam-operated plants and pumps. The Lady Barkly, one of Australia’s first locomotives, was one of his creations.

He came to New Zealand in 1871 to install the “Big Pump” for the Thames goldfield. He’d been commissioned by a consortium of four mine-owners – the United Pumping Association. The mine shafts extended to depths that were often below sea level and required regular pumping to remain dry and operational.

This project’s success led to him being selected in 1874 to design and build a safe, reliable water supply at Western Springs for the burgeoning Auckland city. His design included two massive beam engines, boilers and pumps, as well as reservoirs at Ponsonby and Khyber Pass.

As with the Thames project, the success of the Auckland job pretty much positioned Errington as the logical candidate for designing and building the new drydock.

Calliope’s engines & pumps

While its excavation relied on back-breaking, manual labour, Errington’s design for the steam engines and pumps to empty the drydock were creations of great sophistication. The plant comprised two engines, two pumps and three boilers. They were built by James Watt and Co, the British pioneer company that founded the first legendary steam engine.

Each engine featured Watt’s patented slide valve and surface condenser. Single-cylinder engines with a 34-inch bore and a four-foot stroke, they each carried a 15-foot diameter flywheel weighing 11 tons. The two pumps were double-acting, vertical single-cylinder models. With a 48-inch cylinder bore and a five-foot stroke, they sighed along at 12 to 20 strokes per minute.

Errington tested the system on 23 November 1887. With engines/pumps operating at 20 strokes per minute the drydock emptied in 4.75 hours. If a ship was in the dock (displacing much of the water), the process could be shortened considerably.

Calliope’s engines and pumps were, of course, upgraded with better technology at regular intervals over the years and nothing remains of the original equipment. But an excellent indication of how it all worked can be seen at MOTAT, where one of the beam engines used in Errington’s scheme for Auckland has been superbly restored. It’s the largest in the Southern Hemisphere and the only one of its type in the world.

The Russian scare

Why did New Zealand need a drydock – and why such a large one?

Mainly to service and repair visiting British ships. The responsibility of shaping the development of the new colony required regular visits from British officials. But the number of visiting ships escalated sharply in the early 1880s when the Royal Navy boosted its presence in the South Pacific – a response to souring relations between Britain and Russia.

Russian warships began visiting the South Pacific after the Crimean War (1853 – 1856), much to the alarm of New Zealand and Britain. This festering antagonism was further aggravated by the Anglo–Russian rivalry in Afghanistan.

Widely-labelled the “Russian scare”, the situation led to significant defences being built around New Zealand’s coastal cities. A battery of 64-pounders was established on North Head, for example, and in 1884 four Thornycroft torpedo boats were built.

Predictably, once the Russian scare died down there was little demand for the drydock. Ships visited infrequently, and then only for minor repairs. In fact, the dock was used only four times by Royal Navy ships during the 1914–1918 World War.

That all changed dramatically in WWII – particularly after Japan’s entry into the war and Britain’s heavy losses at her Pacific bases. The drydock became a strategic asset.

In 1942 a tunnel was bored through the hill to Shoal Bay where a Naval Stores Yard was built on reclaimed land. The main electrical substation and the oil fuel depot were shifted into tunnels under the cliffs. And in 1943 the dock was lengthened to accommodate the American heavy cruisers.

Today the drydock remains fully operational – something of a testament to the men who hewed it from the land. It’s now operated by Babcock NZ, contracted to provide engineering services to the Royal New Zealand Navy. It accommodates vessels up to 170 metres in length, with a 22.5 metre beam.

CALLIOPE’S MOST INFAMOUS VISITORpg46-History-300x300px-4

Among the scores of vessels that have used the drydock over the years, one stands out because of her unfortunate end – and the remarkable salvage of nearly nine tons of gold from the wreck.

The 160-metre, 13,400-ton RMS Niagara once held the honour of being the largest-ever vessel to use the drydock. She was launched in 1912 by the Union Steam Ship Company for the Australia-Canada route.

Her end came on 19 June 1940 when, having just left Auckland, she struck a mine off Whangarei. It had been laid by the German cruiser Orion. Though she sank quickly in 121 metres of water, everyone got off safely.

Few knew however that in her strong room was a large consignment of gold from the Bank of England – Britain’s payment to the US for war equipment.

Underwater salvage in 1940 was a very basic science – particularly in such deep water. The Australian company contracted to retrieve the gold used an old coastal steamship (the 60-ton Claymore) as its recovery vessel. The team found the wreck by dragging the Claymore’s anchor along the seabed – and through the minefield. She accidentally detonated two – remarkably without any major damage to herself.

After blasting a hole in Niagara‍’​s hull they used a basic diving bell and a grab to recover 555 gold bars. Thirteen years later they found another 30. Five remain unrecovered.

AUCKLAND’S FIRST DRYDOCK 

Calliope wasn’t New Zealand’s first drydock – nor was it Errington’s first drydock project.

He also designed an earlier dock for the Auckland Harbour Board. It opened in 1878 and was located at what is now Auckland’s Tepid Baths.

Auckland's first drydock
Auckland’s first drydock

While it operated until 1915 it became clear soon after opening that it was too small. Six years after completion the Harbour Board commissioned Errington to build the Calliope dock.

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