The Cutty Sark is a 19th Century Clipper ship. Built in 1869 to transport tea, the ship was built at a time when iron hulled ships were beginning to replace wooden ships. The Cutty Sark has a wooden hull fixed to a metal frame.

For the past 50 years of so, the Cutty Sark has been kept alongside the River Thames in London in dry dock. However, every time it rains, the integrity of the ship was threatened (and believe me, there is plenty of rain in London!)

By Gordon Joly (Own work) [CC BY-SA 3.0 (], via Wikimedia Commons

Sodium Chloride deposits are still found inside the ships hull (left over from its sailing days). The rainwater would dissolve the sodium chloride and the resulting solution would speed up corrosion of the ships hull.

However, electrolysis has been used to turn this unwanted sodium chloride into chlorine gas. Thus, the sodium chloride has been removed from the ship and the life of the hull extended. The electrolyte used is Sodium Carbonate solution.

I still think it would have been easier to build a rain cover around the ship! :mrgreen: Unfortunately, in 2007 the Cutty Sark caught on fire.

Article adapted from an article in New Scientist magazine, ‘Last of the Tea Clippers Saved from Decay’, 10th April 2004, page 25.