Heritage

Iron and steel in ships

Learn about the use of iron and steel in ships

Ships were traditionally made completely of timber. Excavation of historic shipwreck remains from the Early Bronze Age, through the Greek and Roman period into Medieaval times confirms this. The only metal components included copper fastenings in ancient Egyptian vessels, with various forms of iron used from Greek times. This metal was used for anchors, fastenings, braces and other components that could benefit from the greater strength of metal, and the different forms that could be hammered and cast from it.

Gradually the use of metals gained greater attention, particularly by the nineteenth century, when metal work had become a common art. Timber vessels from this period gradually used a greater percentage of iron elements, initially iron bolts, later copper alloy,for fastening timbers, and copper alloy sheeting for plating the external timber hull to reduce destruction from marine organisms. Main structural elements such as the brackets used to secure hull frames to the side of the vessel and the decks, known as "knees", became made of iron. These components now gave far greater strength to the strains imposed on timber hulls by the action of waves and swells, could be made of smaller proportions which allowed greater internal space for additonal cargo and living quarters.

Timber vessels using iron knees and other forms of hull bracing were known as "composite ships". They became increasingly common from the 1870s.

With the perfection of marine steam engine technology, steam powered engines began to be introduced into timber ships, initially paddle steamers, then various forms of compound engines with their associated iron boilers and furnaces for buring fuels to make steam. The earliest steam engine introduced into Australia was aboard the timber-hulled paddle steamer Sophia Jane that operated from Sydney in 1831.

Timber hulls plated with iron sheets began to be seen inthe American Civil War of the 1860s (eg the Monitor and Merimac). Increasing technology wasgradually allowing shipwrights to consider making hulls completely from iron. They began to be seen once the technology for producing the metal, rolling it into sheets, cutting and drilling it, were perfected. These iron ships were first seen from the 1850s. Certainly iron hulled vessels were common sights in Australia from the 1860s alongside timber sailing vessels and timber steamers which still predominated. This was partly due to the lack of shipbuilding yards in Australia that could manufacture the required materials, most vessels being built in the United Kingdom and brought to Australia.

Iron-hulled sailing ships were made in their thousands. Surviving examples afloat today include the James Craig, operated by Sydney Heritage Fleet. Even ship's masts were eventually made from sheets of iron! Iron hulls were favoured because they lasted much longer than timber vessels, were stronger, could carry more cargo, were not as easily damaged by mooring accidents and collisions, and their less bulky component parts meant that they could carry larger cargoes. The strength of iron meant that larger more open cargo holds could be built, leading to greater speeds in stowing a ship and unloading it at the next port. Many hundreds of metal-hulled vessels survive today as shipwrecks within New South Wales' waters.

With the introduction of steel, vessels were gradually built from this material due to its many additional properties.

Page last updated: 31 August 2012