Last updated
Oakum and tools for caulking Drev och drevjarn samt traklubba 004.jpg
Oakum and tools for caulking
Hemp Hennepvezel Cannabis sativa fibre.jpg
Prisoners picking oakum at Coldbath Fields Prison in London Coldbath-fields-oakum-room-mayhew-p301.jpg
Prisoners picking oakum at Coldbath Fields Prison in London

Oakum is a preparation of tarred fibre used to seal gaps. [1] Its main traditional applications were in shipbuilding, for caulking or packing the joints of timbers in wooden vessels and the deck planking of iron and steel ships; [1] in plumbing, for sealing joints in cast iron pipe; and in log cabins for chinking. In ship caulking, it was forced into the seams using a hammer and a caulking iron, then sealed into place with hot pitch. [2]


It is also referenced frequently as a medical supply for medieval surgeons, often used along with bandages for sealing wounds. [3]


The word oakum derives from Middle English okome, from Old English ācumba, from ā- (separative and perfective prefix) + -cumba (akin to Old English camb, 'comb')—literally 'off-combings'.

Oakum was at one time recycled from old tarry ropes and cordage, [1] which were painstakingly unravelled and reduced to fibre, termed "picking". The task of picking and preparation was a common occupation in prisons and workhouses, [1] where the young or the old and infirm were put to work picking oakum if they were unsuited for heavier labour. Sailors undergoing naval punishment were also frequently sentenced to pick oakum, with each man made to pick 1 pound (450 g) of oakum a day. The work was tedious, slow and taxing on the worker's thumbs and fingers. [2] In 1862, girls under 16 at Tothill Fields Bridewell had to pick 1 pound (450 g) a day, and boys under 16 had to pick 1+12 pounds (680 g). [4] Over the age of 16, girls and boys had to pick 1+12 and 2 pounds (680 and 910 g) per day respectively. [4] The oakum was sold for £4 10s (equivalent to £471in 2021 in modern money) per hundredweight (100–112 lb, 45–51 kg). [4] At Coldbath Fields Prison, the men's counterpart to Tothill Fields, prisoners had to pick 2 lb (910 g) per day unless sentenced to hard labour, in which case they had to pick between 3 and 6 lb (1.4 and 2.7 kg) of oakum per day. [5]

In modern times, the fibrous material used in oakum comes from virgin hemp or jute. In plumbing and marine applications, the fibers are impregnated with tar or a tar-like substance, traditionally pine tar (also called 'Stockholm tar'), an amber-coloured pitch made from pine sap. Tar-like petroleum by-products can also be used for modern oakum. "White oakum" is made from untarred material, and was chiefly used as packing between brick and masonry in pre-war home and building construction, as its breathability allows moisture to continue to wick and transfer. [1]


Oakum can be used to seal cast iron pipe drains. After setting the pipes together, workers pack oakum into the joints, then pour molten lead into the joint to create a permanent seal. The oakum swells and seals the joint, the "tar" in the oakum prevents rot, and the lead keeps the joint physically tight. Oakum present in cast iron bell/spigot joints may also contain asbestos. Today, modern methods, such as rubber seals (for example, gaskets or o-rings), are more common. [6]


In Herman Melville's novella Benito Cereno , crew members of a slave ship spend their idle hours picking oakum.

Charles Dickens's novel Oliver Twist mentions the extraction of oakum by orphaned children in the workhouse. The oakum extracted is for use on navy ships, and the instructor says that the children are serving the country.

The Innocents Abroad , a travel book by Mark Twain, also mentions in chapter 37 a "Baker's Boy/Famine Breeder" who eats soap and oakum, but prefers oakum, which makes his breath foul and teeth stuck up with tar.

We tore the tarry rope to shreds
  With blunt and bleeding nails;
We rubbed the doors, and scrubbed the floors,
  And cleaned the shining rails:
And, rank by rank, we soaped the plank,
  And clattered with the pails.

Jack London, in his book The People of the Abyss (1903), mentions picking oakum in the workhouses of London.

Robert Jordan, in Winter's Heart alludes to picking oakum as a punishment among the Sea Folk.

Joshua Slocum in Sailing Alone Around the World, describes caulking his ship the Spray, with oakum.

Guy de Chauliac in The Major Surgery of Guy de Chauliac, frequently cites oakum as a medical supply in his treatments of wounds.

Related Research Articles

<span class="mw-page-title-main">Henry Mayhew</span> British writer and activist (1812–1887)

Henry Mayhew was an English journalist, playwright, and advocate of reform. He was one of the co-founders of the satirical magazine Punch in 1841, and was the magazine's joint editor, with Mark Lemon, in its early days. He is also known for his work as a social researcher, publishing an extensive series of newspaper articles in the Morning Chronicle that was later compiled into the book series London Labour and the London Poor (1851), a groundbreaking and influential survey of the city's poor.

<span class="mw-page-title-main">Ton</span> Unit of mass or volume with different values

Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses.

Pitch is a viscoelastic polymer which can be natural or manufactured, derived from petroleum, coal tar, or plants. Various forms of pitch may also be called tar, bitumen, or asphalt. Pitch produced from plants is also known as resin. Some products made from plant resin are also known as rosin.

The long ton, also known as the imperial ton or displacement ton, is the name for the unit called the "ton" in the avoirdupois system of weights or Imperial system of measurements. It was standardised in the 13th century. It is used in the United Kingdom and several other Commonwealth of Nations countries alongside the mass-based metric tonne defined in 1799, as well as in the United States for bulk commodities.

A plumbing fixture is an exchangeable device which can be connected to a plumbing system to deliver and drain water.

<span class="mw-page-title-main">Caulk</span> Flexible sealant used in construction

Caulk or, less frequently, caulking is a material used to seal joints or seams against leakage in various structures and piping.

<span class="mw-page-title-main">Plastic welding</span> Welding of semi-finished plastic materials

Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat. Welding of thermoplastics is accomplished in three sequential stages, namely surface preparation, application of heat and pressure, and cooling. Numerous welding methods have been developed for the joining of semi-finished plastic materials. Based on the mechanism of heat generation at the welding interface, welding methods for thermoplastics can be classified as external and internal heating methods, as shown in Fig 1.

<span class="mw-page-title-main">Parrott rifle</span> Muzzle loading artillery weapon

The Parrott rifle was a type of muzzle-loading rifled artillery weapon used extensively in the American Civil War.

<span class="mw-page-title-main">Tar</span> Dark viscous organic liquid

Tar is a dark brown or black viscous liquid of hydrocarbons and free carbon, obtained from a wide variety of organic materials through destructive distillation. Tar can be produced from coal, wood, petroleum, or peat.

<span class="mw-page-title-main">Seal hunting</span> Personal or commercial hunting of marine mammal

Seal hunting, or sealing, is the personal or commercial hunting of seals. Seal hunting is currently practiced in ten countries: United States, Canada, Namibia, Denmark, Iceland, Norway, Russia, Finland and Sweden. Most of the world's seal hunting takes place in Canada and Greenland.

Strapping, also known as bundling and banding, is the process of applying a strap to an item to combine, stabilize, hold, reinforce, or fasten it. The strap may also be referred to as strapping. Strapping is most commonly used in the packaging industry.

<i>London Labour and the London Poor</i>

London Labour and the London Poor is a work of Victorian journalism by Henry Mayhew. In the 1840s, he observed, documented and described the state of working people in London for a series of articles in a newspaper, the Morning Chronicle, which were later compiled into book form.

<span class="mw-page-title-main">Uniform Plumbing Code</span>

Designated as an American National Standard, the Uniform Plumbing Code (UPC) is a model code developed by the International Association of Plumbing and Mechanical Officials (IAPMO) to govern the installation and inspection of plumbing systems as a means of promoting the public's health, safety and welfare.

<span class="mw-page-title-main">Pipe (fluid conveyance)</span> Tubular section or hollow cylinder

A pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances which can flow — liquids and gases (fluids), slurries, powders and masses of small solids. It can also be used for structural applications; hollow pipe is far stiffer per unit weight than solid members.

<span class="mw-page-title-main">RBL 7-inch Armstrong gun</span> Naval gun

The Armstrong RBL 7-inch gun, also known as the 110-pounder, was an early attempt to use William Armstrong's new and innovative rifled breechloading mechanism for heavy rifled guns.

<span class="mw-page-title-main">Piping and plumbing fitting</span>

A fitting or adapter is used in pipe systems to connect straight sections of pipe or tube, adapt to different sizes or shapes, and for other purposes such as regulating fluid flow. These fittings are used in plumbing to manipulate the conveyance of water, gas, or liquid waste in domestic or commercial environments, within a system of pipes or tubes.

<span class="mw-page-title-main">Coldbath Fields Prison</span>

Coldbath Fields Prison, also formerly known as the Middlesex House of Correction and Clerkenwell Gaol and informally known as the Steel, was a prison in the Mount Pleasant area of Clerkenwell, London. Founded in the reign of James I (1603–1625) it was completely rebuilt in 1794 and extended in 1850. It housed prisoners on short sentences of up to two years. Blocks emerged to segregate felons, misdemeanants and vagrants.

<span class="mw-page-title-main">Rail profile</span> Cross sectional shape of a railway rail

The rail profile is the cross sectional shape of a railway rail, perpendicular to its length.

<span class="mw-page-title-main">Shipbuilding in the American colonies</span>

Shipbuilding in the American colonies was the development of the shipbuilding industry in North America, from British colonization to American independence.

<span class="mw-page-title-main">George Teamoh</span> American politician

George Teamoh was born enslaved in Norfolk, Virginia, worked at the Fort Monroe, the Norfolk Naval Yard and other military installations before the American Civil War, escaped to freedom in New York and moved to Massachusetts circa 1853, and returned to Virginia after the war to become a community leader, member of the Virginia Constitutional Convention of 1868 and then Virginia Senate during the Reconstruction era, and finally an author in his final years. Teamoh's autobiography is remarkable for his clear rebuke of the military's use of slave labor and the federal government's role both in perpetuating slavery and failing to protect newly emancipated blacks.

I have worked in every Department in the Navy Yard and Dry-Dock, as a laborer, and this during very long years of unrequited toil, and the same might be said of the vast numbers, reaching to thousands of slaves who have been worked, lashed and bruised by the United States government ...


  1. 1 2 3 4 5 Chisholm, Hugh, ed. (1911). "Oakum"  . Encyclopædia Britannica . Vol. 19 (11th ed.). Cambridge University Press. p. 935.
  2. 1 2 Kemp, Peter (1979). The Oxford Companion to Ships & the Sea. Oxford University Press. p. 807. ISBN   978-0-586-08308-6.
  3. de Chauliac, Guy. The Major Surgery of Guy de Chauliac. ISBN   1425773168.
  4. 1 2 3 Mayhew, Henry; Binny, John (1862). The Criminal Prisons of London, and Scenes of Prison Life. Volume 3 of The Great Metropolis. London: Griffin, Bohn, and Company. p.  477.
  5. Mayhew & Binny (1862) p. 312.
  6. Yates, David (1 February 2005). "The Lost Art of Making Lead Joints". Contractormag.com. Retrieved 6 July 2011.