Issues Magazine

Breaking the Ice

The Aurora Australis

The Aurora Australis has the power to push up onto ice and crack it, while her hull shape directs the broken ice around and underneath the ship. Credit: Wayne Papps

By Jonothan Davis

In the 100 years between 1911 and 2011 there have been vast technological changes in the naval architecture of polar shipping.

The first polar ships relied solely on the wind for propulsion. They had no advantage over the sea-ice, which was also propelled by the wind, thus entering the ice was an extremely risky undertaking, if attempted at all.

The Scottish developed the first true ships that could navigate in ice, having been involved in the Arctic whaling ventures from 1750. This Arctic whale fishery was mainly centred on the port of Dundee where, in 1857, a steam engine was trialled in a whale ship. The success of this saw Dundee become the leading Arctic whaling port, and the rise of a new breed of ship design known as a Dundee Whaler. The ships looked much the same as their sailing counterparts, the only external addition being a tall, slim funnel indicating the presence of an engine.

The Dundee steam whalers were, for the era, the best ships for ice navigation. As the only real polar vessels available, they became the leading technology that allowed the “heroic era” of Antarctic exploration to commence.

The Aurora, built at Dundee in 1876, spent her first 10 years as one of the Dundee whaling fleet. Like all Arctic whalers she was made of wood, which allowed the ship to withstand the pressures of the ice when steaming through or when beset. This was very clearly demonstrated in January 1915 when the Aurora, under the command of Joseph Stenhouse, was beset and drifted with the ice for 312 days after landing the Ross Sea party of Shackleton’s Imperial Trans-Antarctic Expedition.

Steel and iron ships available in 1911 were not ice-strengthened. Before welding of steel plates became commonplace, the plates were held together by rivets. These rivets could be broken by the action of the ice on the ship if they were not flush enough with the plating. The plates also buckled under ice pressure and the subsequent leaks were unrepairable at sea. The steel ship would therefore literally come apart, so the early heroic era explorers made do with wood.

The Aurora was built of oak, and the heavy hull frames were braced and stiffened by two tiers of horizontal oak beams on which were built the tween deck and main deck. The engines and boiler were situated aft.

Wooden ships such as the Aurora also had timber sheathing over the hull planking to above the water line. This extra skin protected the hull from ice damage and could be later removed and replaced with new sheathing in dry dock. The Aurora’s sheathing was tough greenheart (Lignum vitae) lined with fur in between the hull planking and the sheathing.

Originally rigged as a barque, John King Davis had Aurora re-rigged as a barquentine, which allowed the vessel to be worked by a smaller crew. Another advantage of the Dundee Whaler was that as a commercial vessel it had a large hold for cargo – an important requirement for delivering the shore parties of Antarctic expeditions. On her first voyage south, the Aurora had every available space taken up with timber for the living huts and an air tractor in a crate on top of it all.

Despite being 40 years old, Aurora was well-adapted for the job in hand, and under John King Davis’ management she was refitted and upgraded with a steamship-style bridge deck and steering. This gave better visibility for the helmsman and the communication of orders. The Aurora was fitted with a compound steam engine, rated at 98 nominal horsepower, which gave her a speed of six knots. Despite the all-important engine for ice navigation, the Aurora was in essence a sailing ship, and one that could sail well, as she demonstrated on her passage from the United Kingdom to Hobart in 1911.

The last wooden ship to be used by an Australian expedition was the Antarctic veteran HMAS Wyatt Earp, in 1947, for the first Australian National Antarctic Research Expedition (ANARE) season. Although this vessel had served the American explorer adventurer Lincoln Ellsworth well on his four Antarctic expeditions, she had very limited ice capability for the emerging needs of modern exploration.

With the sale of the Wyatt Earp, new Australian Antarctic Division Director Phil Law was hampered in his quest to establish a permanent base on the Antarctic continent by the lack of a suitable ship. However, in 1952 he learnt of a new type of vessel built by the J. Lauritzen Line.

The Dan ships, as they were called, consisted of the Kista Dan, Magga Dan, Thala Dan and the Nella Dan. They came with their strong, ice-strengthened, all-welded, smooth hulls, built to Ice Class 1 standard. This standard meant stronger structural integrity and protection for the rudder. These ships also had a fully enclosed crow’s nest containing all the navigation instruments – a major asset in navigating the sea-ice giving the ice pilot a bird’s eye view of the ice conditions. They also had helidecks for helicopter capability added over the stern area. For the first time, information on ice conditions could be obtained well ahead of the vessel, and there was greater ship-to-shore capability.

Kista Dan’s successful pioneering voyage of 1953 saw the establishment of the first permanent base on the Antarctic continent – Mawson Station. Thus began a new era in Antarctic exploration and the era of the all-welded, smooth-hulled steel ships of the J. Lauritzen Line.

In 1989 the multi-purpose Antarctic research and resupply ship, the RSV Aurora Australis, was launched. Her closely-framed, ice-strengthened hull has an ice-clearing shape, and the power to push the ship up onto the ice, whereby the weight of the ship cracks the ice. The shape of the hull is designed to direct the broken ice around or under the ship, so that the ship can proceed forward. This is a much more effective method than in Mawson’s day with the old Aurora, which had perhaps one-twentieth of the power thundering away as it charged at the ice, ramming it with its heavily reinforced bow. It required much skill on the part of Captain Davis to identify the best parts of the ice to ram for success.

Despite the increase in size, the manoeuvrability of today’s ships would astound those of Mawson’s era. The Aurora was 165 feet in length with a single rudder hung on the sternpost. To turn the Aurora around would probably take an arc five times the ship’s length. Today the Aurora Australis has, in addition to her rudder, a transverse bow-thruster and two retractable azimuth stern-thrusters. Not only can she turn almost in her own length, but with the use of her azimuth thrusters she can maintain a station at sea – an important capability in modern marine science and oceanographic operations.

Oceanography and marine science are a significant part of the work of the Aurora Australis. To undertake science at sea the vessel is equipped with eight laboratory spaces, a wet lab for sorting marine specimens, a meteorological room, scientific freezers and culture cabinets. The trawl deck is equipped with trawl winches and net equipment, making biological sampling at sea possible. To acquire oceanographic data, the ship is fitted with a multi-functional instrument winch that generally deploys the Conductivity-Temperature-Depth rosette.

The Aurora Australis’ suite of sonar data echo sounders, transducers and net surveillance sonars are ready at the push of a button for bathymetry logging, fish detection and bottom-type assessment; a far cry from how it was done onboard the Aurora in 1912. According to Captain Davis it took just over an hour to sound 2600 fathoms in fair weather with the Lucas machine. This machine was mechanical and used a lead-weighted wire cable on a large drum. A geared, clock-like scale measured off the depths.

Every era of exploration has the best technology of the day at hand. However, Douglas Mawson’s and John King Davis’ own lifetimes bridged the change from the “old” heroic era to the modern mechanical age – the change from wood to steel, steam to diesel, and from relatively small ships to large cargo capacity ice-breaking ships.

We have seen the role of ships change from a means of getting to Antarctica to full research support, but one thing that has not changed is that ships are still the most vital component of Antarctic logistics.