|Research Points Needed|
|Building Needed||Naval Board|
|Leads To||Improved Coppering|
Ships can be protected from fouling and the ravages of worms by covering them with copper sheeting below the waterline.
Wooden ships are a rich feast for many marine animals, and a home for all manner of weeds and barnacles. Over time, any hull becomes fouled when weeds and encrustations to the point that the ship's speed is compromised. Worse still, given time, worms will eat the planks of the ship to the point where its bottom literally falls out! Other than scraping a beached hull clean, there is no cure; worm eaten timbers have to be chopped out and replaced.
Coppering involves nailing or bolting thin sheets of metal over the whole of a ship's underside. The copper is toxic to worms and weeds, and greatly extends the working life of a ship, and improves its sea keeping qualities.
Historically, coppering was only a partial solution to the problem of fouling. It worked well in keeping the hull clean but, thanks to an electrolytic reaction with iron bolts used to hold the ship together, the bolts rotted away! The iron, copper, and seawater had created a battery, and the (unintentional) iron cathodes were damaged by the reaction.
Copper Bottoms is one of the few technologies that increases the money required to build and/or maintain military forces. In exchange, it significantly boosts ship movement range on the campaign map and, more importantly, their speed in battle.