Hemp in the Age of Sail: Rope, Oakum and Navies
Hemp was a basic maritime material in the age of sail, used for rope and caulking and for part of the sailcloth supply.
Hemp was a basic maritime material in the age of sail, used for rope and caulking and for part of the sailcloth supply. It sat near the top of every navy's supply ledger from the Baltic to the Black Sea for a long time. A first-rate ship of the line carried about 31 miles of rope.[1] The historian Alfred Crosby wrote that in the age of sail hemp was as critical as oil is today.[10]
Getting Fibre from the Plant
Hemp can grow to about 16 feet, which is where the long fibre comes from.[4] To separate fibre from stalk, the stalks first have to rot. They were soaked in ponds or streams, which was quick and whitened the fibre, or left out under the dew, which could take months.[11] Then they were beaten and the fibre was picked out. It was very strong, which made it the material of choice for rope, but moisture trapped inside it caused rot, so it had to be tarred.[4]
What the Royal Navy Needed
In England hemp became a matter for the Crown. Parliament passed an act on sowing flax and hemp in 1533, and similar legislation followed in 1563. One local history says farms of 60 acres had to grow a quarter acre of hemp per 60 acres, while another account gives one acre for the 1563 law. Demand from the navy and trading companies made the crop common. Because retting fouled the water supply, the law also banned soaking hemp in streams where animals drank.[11]
Home production still fell short. The best hemp grew in the interior of Russia and left through Baltic ports like Riga, which is why it was called Riga hemp.[1] On 3 August 1663 the navy administrator Samuel Pepys ran a trial in the ropeyards comparing English and Riga hemp. His diary records that Riga hemp proved stronger, and that English hemp beat every other kind but Riga.[3]
The Chatham Ropery
The best-preserved place where hemp became rope is Chatham Dockyard in Kent, where rope has been made since 1618. Raw hemp waited in stores dating from 1729. The work started in the hatchelling house of 1787, where workers drew the fibre across boards set with long iron pins to straighten it, softening it with whale oil. In 1803 nineteen hatchellers worked there. The fibre was then spun into yarn, treated against rot in the tarring house, dried and formed into strands.[1]
The last step explains the building's length. Three strands are twisted together in the opposite direction to make rope, and that opposing tension holds it together.[2] Since the work runs in a straight line, the ropery built between 1786 and 1791 is more than 1,100 feet long. Over 20 miles of a first-rate's rope went on the rigging alone.[1] The tar got on hands as well, which earned British sailors the nickname Jack Tar.[4] Rope was gear that constantly needed replacing, so demand did not stop in peacetime.
During the Napoleonic Wars, in 1812, a second storey doubled the hemp stores. Mechanical spinning came only in 1864, and women took over as machine minders. A company called Master Ropemakers still makes rope commercially on the site.[1][12]
Depending on Russia
England was not alone in depending on the Baltic. According to Crosby's 1961 study, the young United States' merchant fleet and navy could not have operated without iron, sailcloth and above all hemp from Russia. American hemp existed but was poor, and it soon deteriorated in salt water. For Russia, Britain was the best market, and for Britain, Russia was the best source of essential naval stores.[10]
The Americans built their own ropewalks. A frigate the size of USS Constitution needed about 40 miles of cordage. The ropewalk at the Charlestown Navy Yard went up in the mid-1830s.[4] A similar building survives at Mystic Seaport, a 250-foot section of the ropewalk that Bourne Spooner built at Plymouth in 1824, over 1,000 feet long in its original form. Plymouth Cordage used it until 1947.[2]
Sailcloth
The word canvas comes from the Latin word for hemp, but sailcloth was a different story from rope. It was woven from hemp or flax yarn, and flax seems to have been preferred for most sails. Russia and Silesia supplied canvas in huge quantities, and in the early 19th century sailors rated the flax canvas of Bridport and Crewkerne in England second only to Dutch. A US Navy contract of 1800 specified flax. A ship the size of Constitution needed about 350 bolts for a suit of sails. Cotton was tried from the 1830s, and conservative officers took decades to accept it.[13]
Caulking and Oakum
Hemp's second life on board started when the rope was finished. Worn tarred rope was unpicked into fibres, and the result was called oakum. A caulker drove it into the seams between hull planks with a caulking iron and mallet and sealed it with hot pitch. New oakum is still made from hemp or jute treated with tar.[5]
Ashore the fibre had a different reputation. Picking oakum was standard work in prisons and workhouses, given to those not fit for heavier labour. At Tothill Fields in London in 1862, girls under 16 picked one pound a day and boys one and a half. Sailors under naval punishment did the same, at about one pound a day.[5]
Hemp in the Ottoman Navy
On the Ottoman side rope was also made of hemp, and the supply records show it was state business. A 2003 study at Marmara University says shipbuilding was the main use of hemp in the 16th century. Growing areas at Çarşamba, Terme and Fatsa were lands attached directly to the imperial arsenal, the Tersane-i Âmire. A hemp superintendent gathered whatever was short from a growing region stretching from Kastamonu to Rize. Quality was a separate criterion in purchasing, and the ledgers also recorded regional output and unit prices.[6]
The fibre fed dozens of provincial yards as well as those in Istanbul. Records from the early 18th century mention about 65 provincial yards, whose hulls came to Istanbul for fitting out.[7] Hemp kept its place on the Black Sea for a long time. In 1918 a venture called the Hemp Production and Export Company was founded at Kastamonu, though the researcher Gülşah Kaya says she found no evidence that it ever operated.[8]
Manila Hemp
A Philippine plant took hemp's place. Abacá is a relative of the banana with no botanical connection to hemp, but its fibre reached the market as Manila hemp. The Mystic Seaport record says it was the preferred fibre by the 1830s. It was cleaner than hemp and needed no tar against heat, rain and salt water. From 1851 Plymouth Cordage supplied manila running rigging for America's Cup contenders.[2] Price also favoured it. From the 1880s the Charlestown ropewalk used cheaper Manila alongside American hemp.[4]
The change did not happen overnight. Constitution went into dock in June 1927 for a four-year restoration costing nearly $1 million, and the rigging came from the yard's own ropewalk. Plan number 50670 of 5 April 1929 shows only hemp in the rigging, boltropes and cables. About 67 tons of rope were made for the job.[4]
From the Tax Act to the War
The US Congress passed the Marihuana Tax Act on 2 August 1937. Fibre output was already low, having fallen to 500 tons a year in 1933. The claim that the act was really aimed at the hemp industry still circulates, but it comes mostly from writers with an interest in the subject.[9] Japan's capture of the Philippines reversed the position. With Manila cut off in 1942, the US Department of Agriculture released the film Hemp for Victory and asked farmers to grow hemp for navy rope. About 400,000 acres were planted between 1942 and 1945.[9][14] Each US battleship needed 34,000 feet of rope.[4]
Nylon ended that last revival. After 1962 the Charlestown ropewalk made only nylon rope, and it closed in December 1971.[4] Hemp is used today on historic ships, in caulking and at places like Chatham. Wind is returning to merchant ships through sail-assisted propulsion, with rigid wings and rotors in place of rope, and the aim of these systems is to cut marine fuel consumption.
Frequently asked questions
What was hemp used for in shipping?
Hemp was a basic maritime material in the age of sail, used for rope and caulking and for part of the sailcloth supply.
What was Riga hemp?
Hemp grown in the interior of Russia and shipped through Baltic ports like Riga. It was the quality the Royal Navy looked for in rope.
What is oakum?
A material made by unpicking old tarred rope into fibres. It is driven between the planks of a wooden hull as caulking.
What replaced hemp rope?
First Manila rope made from Philippine abacá, and after the mid-20th century synthetic fibres such as nylon.
Sources
- The Historic Dockyard Chatham. Master Ropemakers, Our Buildings.
- Mystic Seaport Museum. Plymouth Cordage Company Ropewalk.
- Samuel Pepys. Diary, 3 August 1663, pepysdiary.com.
- USS Constitution Museum. Ropemakers of the Navy, Part II, 21 October 2016; Wikipedia, Hemp.
- Wikipedia. Oakum.
- Marmara University. Karadeniz Bölgesinde Kendir-Keten Üretimi ve Kullanım Alanları (XV. Yüzyıl Sonu XVII. Yüzyıl İlk Yarısı), 2003, abstract.
- TDV İslam Ansiklopedisi. Tersane-i Âmire entry.
- Gülşah Kaya. Kastamonu'da Bir Kendir Şirketi Kurma Girişimi, Kastamonu İnsan ve Toplum Dergisi, 2023.
- Wikipedia. Marihuana Tax Act of 1937.
- Alfred W. Crosby. America, Russia, Hemp, and Napoleon, Boston University thesis, 1961, abstract.
- Haxey Walkers. Linen and Hemp Production in the Isle; Ecohustler, The UK's Compulsory Cannabis Law; National Archives, Public Act 24 Henry VIII c. 4, catalogue entry.
- The Historic Dockyard Chatham. Master Ropemakers, About Us.
- USS Constitution Museum. From Hemp and Flax May Canvas Sails, 19 July 2016.
- Wikipedia. Hemp for Victory.
