Composite ship

The technique of composite ship construction (wooden planking over a wrought iron frame) emerged in the mid-19th century as the final stage in the evolution of fast commercial sailing ships.

Construction of wrought iron hulled vessels had begun in the 1820s and was a mature technology by the time of the launch of the SS Great Britain in 1843. However iron hulls could not be sheathed with copper alloy (due to bimetallic corrosion) and so would become festooned with drag-inducing weed during long voyages in the tropics.

The wooden planking of a composite ship allowed the copper sheathing essential for fast ocean crossings under sail while the iron frame made the ship relatively immune from hogging and sagging, and took up less interior space than wooden framing.

The brief reign of composite clippers as the fastest mode of transport between Europe and Asia was brought to a close by the opening of the Suez Canal in 1857 and ongoing improvement in the performance of steam ships.

Today only four ships of this type survive, in various states of preservation or decay.

• City of Adelaide (1864), Passenger Clipper, Threatened, Irvine, Scotland

• Cutty Sark (1869), Tea Clipper, Under restoration, Greenwich, England

• Ambassador (1869), Tea Clipper, Beached skeleton, Estancia San Gregorio, Chile

• HMS Gannet (1878), Naval Sloop, Restored, Chatham, England

Further reading

• www.globalsecurity.org, article on copper sheathing
• www.histarmar.com.ar, Spanish language article on Clipper Ambassador with photos of remaining iron structure