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Copper and Brass in Ships

The use of copper for sheathing the bottoms of wooden ships was first introduced in the middle of the 18th Century. The oak timbers of the old wooden sailing-ships were always liable to be attacked by the dreaded teredo or shipworm when in warm seas. This is not really a worm but a boring mollusc which can work its way into quite hard wood by means of sharp teeth at the end of the shell. Once inside, the pest goes whither it will, usually with the grain, and deposits its eggs in the hole which it has bored. Quite stout timbers, including the piles used for fronting wharves, become so riddled with the shipworm's tunnels as to be rotten beyond repair. Copper sheathing was tried as a remedy by the Admiralty, who had the frigate Alarm sheathed with copper in 1761. This not only protected the ship but also improved her speed by keeping her bottom freer from barnacles and other marine organisms. The experiment was so successful that within a few years most of the Fleet, including the flagship Victory, were given copper bottoms; and the practice was naturally extended to the large East Indiamen and other vessels sailing in tropical waters.

Copper was used exclusively until 1832. In that year G.F. Muntz patented a new brass containing 60 per cent copper and 40 per cent zinc which is known either as Muntz metal or 'yellow metal' in the trade. As it was much cheaper and almost as effective, it inevitably supplanted copper for sheathing and was also widely used on wharves. The advent of iron ships fifteen to twenty years later altered the position, but Muntz metal sheets continued to be used in smaller vessels for this purpose. The Admiralty now specifies approximately the same mixture of copper and zinc, with an addition of about 1 per cent of tin; this is known as 'naval brass'. During the Second World War nearly all Admiralty motor fishing vessels and other small craft operating in warm harbours and seas were sheathed in Muntz metal on a base of tarred felt.

Another notable feature of the warships of Nelson's day was the resurrection of brass cannon. Some ships were equipped with large brass carronades, a terrible weapon which, by contemporary accounts, was feared much more than the conventional cast iron guns because of its far greater accuracy and range.