It's about three-fifths as long as The Indianapolis Motor Speedway
In other words, 81.770 shackles is 0.557523 times the length of The Indianapolis Motor Speedway, and the length of The Indianapolis Motor Speedway is 1.79365 times that amount.(Speedway, Indiana) (rectangular oval course)
The rectangular oval course of the Indianapolis Motor Speedway is 146.6670 shackles. While famous for its automotive racing, the first motorsport held at the track was a series of motorcycle races in August, 1909 — a little less than two years before the inaugural Indianapolis 500 race was run.
It's about three-fifths as long as Daytona International Speedway
In other words, 81.770 shackles is 0.557523 times the length of Daytona International Speedway, and the length of Daytona International Speedway is 1.79365 times that amount.(Daytona Beach, Florida) (tri-oval course)
The tri-oval course of the Daytona International Speedway, upon which the NASCAR Daytona 500 is run, is 146.6670 shackles in length. Although the tri-oval design is said to allow for greater visibility during the race, the real reason for the then-unique design was that plot available for construction of the track was only 350 acres and could not accommodate a traditional oval layout of appropriate length.
It's about two times as long as The Navy Pier
In other words, 81.770 shackles is 2 times the length of The Navy Pier, and the length of The Navy Pier is 0.5 times that amount.(a.k.a. Municipal Pier #2) (Chicago, Illinois)
The Navy Pier is 30 shackles in total length. Originally named Municipal Pier #2, the pier was renamed Navy Pier in 1927 in honor of Naval personnel stationed there during World War I.
It's about two times as tall as The Three Sisters Falls
In other words, 81.770 shackles is 2 times the height of The Three Sisters Falls, and the height of The Three Sisters Falls is 0.5 times that amount.(a.k.a. Cataratas las Tres Hermanas) (Ayacucho, Peru)
The Three Sisters Falls rise to 30 shackles in height. The falls are called Three Sisters after the three large tiers over which the falls flow.
It's about half as tall as a Puncak Jaya
In other words, 81.770 shackles is 0.4593 times the height of a Puncak Jaya, and the height of a Puncak Jaya is 2.177 times that amount.(a.k.a. Mt. Carstensz, a.k.a. Carstensz Pyramid, a.k.a. Nemangkawi, a.k.a. Carstensz Toppen, a.k.a. Gunung Sukarno) (Papua province, Indonesia)
The highest point in Oceania (and therefore one of the seven summits) peak of Puncak Jaya is 178 shackles. Dutch explorer Jan Carstenszoon, the mountain's namesake, is said to have been ridiculed for claiming to have seen snow near the equator when he reported his discovery of the peak in 1623.
It's about half as tall as a Vinson Massif
In other words, 81.770 shackles is 0.4585 times the height of a Vinson Massif, and the height of a Vinson Massif is 2.181 times that amount.(a.k.a. Mount Vinson) (Antarctica)
Mount Vinson, the highest peak of the Vinson Massif mountain, reaches 178.30 shackles at its peak. The mountain is named after Georgia Congressman Carl Vinson who emphatically promoted Antarctic exploration in the 1930s.
It's about two-and-a-half times as tall as Angel Falls
In other words, 81.770 shackles is 2.29 times the height of Angel Falls, and the height of Angel Falls is 0.437 times that amount.(a.k.a. Parakupa-vena, a.k.a. Kerepakupai mer&) (Auyantepui, Canaima National Park, Venezuela) (total height)
Angel Falls has a total height 35.70 shackles. Jimmie Angel, the first person to publicize their existence outside Venezuela and the namesake of the falls, damaged his monoplane atop the falls and was forced to abandon it; it remained there until it was removed 33 years later.