The Great Barrier Reef: A Navigational Nightmare

The Great Barrier reef is a truly unique natural phenomenon. It is the largest structure ever built by living organisms, certainly on the Earth today and quite possibly in the 4.5 billion-year history of this planet. For as long as aboriginal and Torres Strait islanders have lived on this continent, the reef has been a rich hunting ground, providing a ready source of nutrition in an environment that was generally both benign and healthy. Then along came the first Europeans.

As discussed in the last issue of Camper, there’s likely been interactions between the sea-going explorers of other nations and settlers dating back to a thousand years ago. This includes everyone from Chinese merchant explorers seeking to take advantage of natural resources, to ships and European explorers mostly bent upon seeking exploitable opportunities around their bases in the Spice Islands (today the nation of Indonesia and its surrounding countries).

However, the records of these interactions have for the most part been lost, if they ever existed at all. Today we have only a handful of curiosities (coins, statuettes and other curios and anachronous built structures), along with strange rock art and dreamtime stories from aboriginal groups in the far north to use as evidence of this early contact.

The first extensive and accurate observations of the region, and more specifically the Great Barrier Reef, come from people like explorer Lieutenant James Cook as he attempted to navigate the difficult waters along the east coast of Queensland. Cook had no idea of the difficulties he was steering into as he headed up the coast of Australia in 1770.

His ship was a Whitby collier, chosen for its inherent strength and good sailing qualities. She wasn’t a fast ship but with a broad flat bottom she suited shallow waters and her strength made her easy to beach for repair or maintenance, qualities for which Cook and his crew would be grateful. The ship’s name was changed to His Majesty's Bark the Endeavour, and she was to become one of the most famous ships ever built.

The Endeavour passed Sandy Cape at the northern tip of Fraser Island on May 21 and at noon on May 28 came upon its first shoal water, in other words its first reef. The Great Barrier Reef is not a single structure, but a vast series of over 2900 individual reefs, ranging from tiny platforms of coral that just reach the surface at low tide to massive unbroken sweeps of coral that can be tens of kilometres long and wide.

The problem for Cook and his crew was that the prevailing winds were from the south-east, which tended to push him both northwards and towards the shore.

A lee shore, as this is called, is one of the most concerning for ships that are dependent on the wind, as severe weather can push the ship onto the land, even against the holding power of a number of anchors. While sailing ships were quite capable of being navigated against the wind direction in open water, this required considerable sea room for the extensive manoeuvring this involves and Cook was sailing into a vast nest of reefs with narrow channels and shallow water which prevented this sort of freedom.

So, instead, they’d have two or even three of their small boats sailing ahead, trying to navigate channels between reefs, and have observers – often Cook himself – at the mast top, observing as they crept along under shortened sails.

At night most of the time they anchored until first light gave them some idea of the waters ahead. Occasionally Cook landed on islands or high points on the mainland to check the reefs and channels to the north.

The further north he went the denser the reefs and shallower the water became and the less hope he had of being able to return south or navigate his way ahead.

Some sections of the reef remain uncharted in detail even today and are simply marked on maps as dangerous for navigation.

Throughout this time of intense focus on navigating his ship Cook maintained the discipline of objective and thoughtful mapping of this unknown coast, and observations of various celestial phenomena which would verify his deductions of longitude and aid the navigation of those who might follow. His maps remain wonderful examples of his skill and in many places are essentially unchanged from when first drawn.

At 10:30pm on June 11 the Endeavour struck hard upon the edge of a reef off what is today labelled Weary Bay, between Trinity Bay and Cooktown. Despite all their best attempts the crew was unable to float the ship until 10:20pm on the following night, after throwing overboard all manner of stores and ship’s fittings. The anchors, which had been used to winch the ship off the reef, were all recovered, bar one, which had become lodged in the bottom. It was found that the three pumps on the ship (out of four) that were working would keep up with the leakage through the damaged hull and the Endeavour crept away south-west before anchoring for the night.

One of the crew had been on a ship in the Atlantic which had sailed from the United States back to Britain with a badly damaged hull, which had been “fothered” with a sail coated with pitch, wool and animal dung. Cook put one of his crew in charge of the process and it was trialled and found to cut the flow of water into the ship to the point where just one pump was needed, giving the crew a rest from the hard physical labour of working them.

One of the ship’s boats was sent off to find a harbour of some sort where the ship could be beached for repairs, and this was found just up the coast, where a river entered the sea. This was where the Endeavour’s strength and build type was of value. She could be brought over the entrance sand bar and hauled up onto the bank and partially rolled onto her side for repair work.

The essential restoration was complete in only a few days, but strong contrary winds and unsuitable tides prevented the ship leaving the river for over a month, after which it became a matter of again turning north and continuing to battle through the reefs.

The Endeavour did escape through a channel in the outer reef into the open ocean, but Cook wanted to determine that there was a passage between the northern tip of Australia and New Guinea so he again entered through the reef, after nearly being washed onto it, and battled through until he proved the existence of Torres Strait.

The Great Barrier Reef is still a major shipping hazard, but modern navigational aids and strict regulations keep ships far enough from the reef to prevent modern replication of Cook’s dilemma and the Endeavour’s fate.