What is the difference between a barrel and a drum?
The short answer is: A barrel is a measurement of 42 gallons and a drum is 55 gallons in the marine and oil industry. Barrels were usually made of wood staves and depending on the liquid carried in them came in various standard sizes. Drums are made of steel and can be used for any type of liquid but in the marine field are usually used to deliver lubricating oils and/or anti-freeze.