To find the circumference of a circle, you can use the formula:
\[ C = \pi \times d \]
where \(C\) is the circumference and \(d\) is the diameter. Given that the diameter of the shipping drum is 20 inches and using \( \pi \approx 3.14 \), you can calculate the circumference as follows:
\[ C = 3.14 \times 20 \] \[ C = 62.8 \text{ inches} \]
Therefore, the circumference of the base of the shipping drum is approximately 62.8 inches.