Copper coating is the practice of protecting hulls under water or boats from the corrosive effects of brine and biofouling through the use of copper plates affixed to the outside of the stomach. It was pioneered and developed by the Royal Navy during the 18th century.
Video Copper sheathing
Development
Damage to wooden hull is a significant problem during the Sail Age. The ship's hulls are under continuous attack by shipworms, barnacles and various sea weeds, all of which have some adverse effects on the ship, whether structurally, in the case of worms, or affecting speed and handling in weed cases. The most common method to solve this problem is through the use of wood, and sometimes cause, sheathing. Resilient wood coating effectively provides the non-structural skin of the stomach for the worms to attack, and can be easily replaced in dry dock at regular intervals. Weed, however, grew rapidly and slowed the ship. The tin sheath, while more effective than wood in reducing this problem, is too heavy and reacts badly with the ship's iron bolts.
Even older than the veil method is the variety of replication and payment techniques. There are three main substances used: White objects, which are a mixture of whale oil, resin and sulfur; Black objects, a mixture of tar and pitch; and Brown stuff, which only sulfur is added to the Black stuff. It is common practice to coat the stomach with the substance chosen, then cover it with a thin layer of thin wooden outer layers.
The use of copper coating was first proposed by Charles Perry in 1708, although rejected by the Navy Council on the basis of high costs and perceived maintenance difficulties. The first experiment with copper coating was done in the late 1750s: the undersides and sides of some fake boats and keels were lined with copper plates.
In 1761, the experiment was expanded, and the HMS-i-Alarm fighter was ordered to have all its copper base parts in response to the dire conditions in which he returned from the West Indies service. HMS Alarm was chosen because, in 1761, a letter had been sent regarding the condition of the ship, saying that the worms of the waters had taken a significant load on the ship's hull. Before the copper plate was applied, the hull was covered with Soft items, which were only hair, yarn and brown paper. Copper is excellent, both in protecting the stomach from the invasion of the worm and preventing the growth of weeds, when in contact with water, copper produces a toxic film, mainly composed of copper oxychloride, which blocks these marine organisms. Furthermore, as the film is slightly soluble, it slowly drifts, so there is no way in which marine life can stick to a ship. However, it was soon discovered by Admiralty that the copper bolts used to hold the plate to the hull had reacted with the iron bolts used in the construction of the ship, making many bolts almost useless. In 1766, due to the bad condition of the iron bolt, Alarm 'copper was removed.
After this experiment, and obstructed by an unexpected and unfathomable electrolytic reaction between copper and iron, the tin coating is on trial again, although it does not fit the task, since the plates tend to fall from the stomach quickly. In 1764, the second ship, HMSÃ, Dolphin , was coated with copper, specifically to prepare it for the discovery voyage in tropical waters. The hull of Dolphin was spotted in 1768 after the ship twice circled the globe; there is significant corrosion of the iron component of the stomach, which must be replaced. In 1769, another attempt was made to stain the hull of a ship, this time on a new ship built using a bolt made of copper alloy. The result is much more profitable nowadays, but still a problem with permanent bundling. The beginnings and intensification of the 1773 war with the Americans took the focus of the piracy problem necessary to enable a full scale copper program.
Maps Copper sheathing
Implementation area
With the American war in full swing, the Royal Navy began to pollute the entire fleet base in 1778. This will not happen but for war. This also happened because in 1778 Mr. Fisher, the Liverpool shipbuilder (who traded fast with West Africa) sent a letter to the Navy Council. In it he recommends "copper coating" as a solution to the problem of shipworms in warm tropical waters, and affects the velocity of the seaweed vines attached to the hull. The letter itself does not survive and is indirectly referred to in other official correspondences organized by the National Maritime Museum, it may contain or coincide with a new technical breakthrough critical to protecting streaked iron by applying thick paper between copper plates and ship hulls. This has recently been successfully tested (probably) in Jupiter . This breakthrough is what will win the Admiralty. The letter was seen by the Superintendent of the new Navy Council Charles Middleton, who had a major problem at the time by supplying over 100 ships for the American Revolutionary War (1775-1783), which was exacerbated in the same year (1778) by French opportunism in declaring war against Britain to support American rebels. This effectively changed what became a local civil war to a global conflict. Others followed Spain (1779) and the Netherlands (1780). Britain must face three of its biggest rivals, Middleton takes the view that Britain is "outnumbered at every station", and the Navy is asked to "release us from the dangers of the moment". He understands that copper allows the navy to stay in the ocean longer without the need to clean and repair the underwater hull, making it a very attractive, if expensive, proposition. He had to expand the Navy but there was no time to add fleets, and limited resources were available. It took five years and 2,000 trees to build a battleship. But he could renew the existing fleet, he understood Fisher's solution and on January 21, 1779 wrote to Admiralty. He also petitioned King George III directly on this "most important issue" for the necessary funding. He brings the HMS Bellona model which shows the copper base to illustrate this method. The King supports it because of what is an expensive process for untested technology. Each vessel averages 15 tons of copper used on average of 300 plates. All copper is supplied by British mines (the only country in the world at that time who can do it). The largest mine is Parys Mountain in Anglesey, north Wales. Fortunately, the Parys mine recently started large-scale production and has ravaged the British market with cheap copper; However, the 14 tonnes of metal required for copper, the 74-gun third-tier liner from the line is still worth  £ 1500, compared to  £ 262 for timber. The benefits of increasing speed and time at sea are considered to justify the costs involved. Middleton in May 1779 placed orders at the Portsmouth Docks to litter all ships up to and including 32 weapons when they next entered the dry dock. In July, the order was expanded to include ships with 44 weapons and fewer. In total there are 51 ships in a year. It was then decided that the entire fleet should be fitted with copper, due to the difficulty in maintaining a mixed fleet of copper and non-copper vessels. In 1781, 82 ships of the line had been coppered, along with fourteen 50-gun ships, 115 frigates, and 182 unmanned vessels.
All of this was too late to prevent the loss of American colonies, but in the meantime France threatened the lucrative sugar trade in the Caribbean, which was calculated at the time was more important for British interests than 13 colonies. Sugar trade paid for the costs of the American Revolutionary War (1775-1783) and the Anglo-French War (1778-1783). The ships that had just been transported by the untested Royal Navy were successfully used by Rodney in defeating France at the Battle of the Saints from Dominica in 1782.
By the time the war ended in 1783, the problem with the hull's hull once again became clear. Finally, suitable alloys for hull hull are found, namely copper and zinc. At great expense, Admiralty decided in 1786 to proceed with the re-hijacking of each ship in the navy, thus finally eliminating the problem of bolt corrosion. This process lasted several years, after which no significant changes to the copper system were required and metallic coating remained the standard method for protecting the underlying hull until the appearance of modern anti-fouling paints. In the 19th century, pure copper was partially replaced by Muntz metals, 60% copper alloys, 40% zinc, and less iron. Muntz metal has a cheaper advantage than copper.
Civil use
With the widespread adoption of the Royal Navy, some shipowners used this method on their merchant ships. One copper vessel was listed on Lloyd's of London list in 1777, a slipper sloop "Hawke", 140 tons. This special ship impresses the admiralty when examined by Sandwich in 1775 in Sheerness after a 5-year journey to India. In 1786, 275 ships (about three percent of the merchant fleet) were fitted with copper. By 1816, this had risen to 18 percent of British merchant ships. Copper sheets are exported to India for use on ships built there. In the late 18th and early 19th centuries, about 30 percent of Indian ships were fitted with copper.
The owner of the merchant is interested in the savings made possible by copper coating, despite initial expenditure. Because copper is expensive, only better owners tend to invest in this method, and consequently the use of copper veils tends to show the well-found and maintained vessels, which causes Lloyd's of London to impose lower insurance premiums, because ships are a better risk. From here rooted the phrase "grounded copper" as an indication of quality,
Coppering is more commonly used on merchant ships that sail in warm waters. Sailing ships in cooler, cooler waters often continue to use replaceable wooden sheaths. Timber-harming organisms are less a problem for these ships and they are often routinely escorted - an operation that can cause massive damage to expensive copper. Coppering is widely used in slave ships. After the abolition of the Slave Trade Act became English law in 1807, the slave trade became illegal so the slaves appreciated the speedboats more likely to avoid the Royal Navy patrol boats intent on capturing them.
Humphry Davy's experiments with copper plating
In the late 18th century until the beginning of the 19th century, Sir Humphry Davy conducted many experiments where he had various copper thicknesses that sank on shore and then measured how much sea water had degenerated respectively. Different metal sheets remained in seawater for four months and then examined. Two harbor vessels are also used in this test, one with a zinc band, the other with iron. Both zinc and iron become covered carbonates that allow weeds, live plants and insects to attach themselves to the metal. Sheets that have poured iron or zinc free of inherent life forms or discoloration. The main purpose of this experiment is to determine how to reduce the corrosion caused by seawater on unprotected copper coatings. Unprotected copper, like that not coated with other metals like iron, will quickly change from reddish to greenish corrosion. When other metals are mixed in copper in a ratio from 1/40 to 1/150, there are no visible corrosion marks and minimal weight loss. When the ratio is changed to 1/200 and 1/400, there is significant corrosion and weight loss. Davy concludes that cast iron, which is the cheapest to produce, is best for protecting copper because soft iron and zinc are declining rapidly.
Other uses
The term copper-bottomed continues to be used to describe a safe, successful effort, plan or investment. Copper-fastened (and verb forms
See also
References
External links
Source of the article : Wikipedia
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