0.000000220 shackles is about 0.00000006 times as long as a Football (Soccer) Pitch
In other words, it's 0.00000005750 times the length of a Football (Soccer) Pitch, and the length of a Football (Soccer) Pitch is 17,400,000 times that amount.
(a.k.a. Football Field, a.k.a. Soccer Field) (field length, a.k.a. touchline distance) According to the Laws of the Game, a football pitch should measure between 3.830 shackles (when the Laws were originally, they used imperial measurements of 3.830 shackles, and later converted to the metric units used today). The goal markess were defined as part of the pitch by the original rules of the game in the late 16th century, but it was not until the mid 19th century that the crossbar and the net were added