A team of underwater archaeologists from the National Museum of the Philippines conducted archaeological excavations of a shipwreck located in Barangay Laylay, Boac, Marinduque from May 27, 2014 to June 6, 2014. Found approximately 100 m from the shoreline and lies 4 m below sea surface level, its wooden remains measured about 20 m long and 2 m wide. Besides the hull remains, other archaeological materials included a heavily encrusted cannon, unknown metal remains probably from an anchor, and copper and/or lead sheathing found attached to parts of the keel and planks.
Sheathing wood can be traced back to the early 4th century Before Common Era (BCE) to protect the ship’s hull from attacks of shipworms. An ancient ship built with lead sheathing and fastened by brass and copper nails dated back to about 100 Common Era (CE) was found in the Lake Hemerose, Naples in Italy. Roman vessels found in Lake Nemi were also built with lead sheathing fastened by gilt nails. The use of lead sheathing by the Spanish during the 15th century CE was followed by a series of attempts to improve sheathing methods by the English.
The use of copper sheathings on the other hand has been proven effective and was later adopted by the Royal Navy. By the 18th century CE, copper sheathings fastened with copper bolts have protected ships’ hulls from attack of wood-boring organisms as well as from unwanted marine growth below the waterline. As a result, the wooden sailing vessels were built with protection and were added with speed (less drag), and the warships were allowed to spend longer period at sea before being required for a routine repair and maintenance.
Interestingly, in 1775, an American patriot, David Bushnell built his mini submarine, the American Turtle, to annihilate the British fleet. The mini sub was equipped with a bit that could drill an enemy ship’s hull, which is deployed with an improvised 150-lb gunpowder timed-bomb. The copper sheathings of the British ship Eagle, however, have rendered Bushnell’s Turtle futile despite series of attempts in 1776. — This story was first published on National Museum Site