Oakum
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.
Today, modern methods, such as rubber seals (for example, gaskets or o-rings) are more common.
Tar River
North Carolina was originally a naval stores colony—that is, the blanket of long leaf pines that covered the coastal plain was used by the British Navy for ships' masts and the pine pitch was used to manufacture tar caulking for vessels. The river derives its name from its historic use as a major route for tar-laden barges as they headed to the sea. The city of Tarboro is on the banks of the river. Recent research conducted by East Carolina University, Greenville and Pitt County historians has uncovered documentation noting that before the Civil War, the North Carolina Legislature had appropriated funds to construct dams and locks on the Tar River in an attempt to facilitate almost year round navigation for the farm products and naval stores shipping plus passenger boats which were travelling between Tarboro, through Greenville to Washington.
Among the towns and cities along its course are Louisburg, Rocky Mount, Tarboro, and Greenville. The village of Old Sparta was formerly an important riverport on the Tar, but has declined in the 20th century.