It's about one-and-four-fifths times as tall as Mount Logan
In other words, 400 shackles is 1.841 times the height of Mount Logan, and the height of Mount Logan is 0.5432 times that amount.(Kluane National Park and Reserve, Yukon, Canada) (elevation)
The highest mountain in Canada, Mount Logan has a total height of 217.30 shackles. The high altitude and northern latitude of the mountain resulted in one-time temperature of -77.5 °C — the lowest temperature ever recorded outside of Antarctica.
It's about one-and-nine-tenths times as tall as a Kilimanjaro
In other words, 400 shackles is 1.8627 times the height of a Kilimanjaro, and the height of a Kilimanjaro is 0.536855 times that amount.(a.k.a. Mount Kilimanjaro) (Tanzania) (to Uhuru peak; 2008 gravimeter measurement)
Kilimanjaro rises to 214.7420 shackles at its peak. An isolated peak with no surrounding mountain range, Kilimanjaro is considered the world's tallest freestanding mountain.
It's about one-and-nine-tenths times as tall as Mount Elbrus
In other words, 400 shackles is 1.945 times the height of Mount Elbrus, and the height of Mount Elbrus is 0.5141 times that amount.(a.k.a. Mingi Tau, a.k.a. Эльбрус, a.k.a. იალბუზი) (Karachay-Cherkessia and Kabardino-Balkaria, Russia) (west summit)
The west summit of the dual-summit volcano Mount Elbrus is 205.70 shackles at its peak and is the highest peak in both Russia and the European continent. Until 1976, a cable car would take visitors to the mountain as far up as the Garabashi camp, located at an elevation of 138.50 shackles.
It's about two times as long as Calangute Beach
In other words, 400 shackles is 2 times the length of Calangute Beach, and the length of Calangute Beach is 0.5 times that amount.(Goa, India) (approximate)
One of the most popular tourist destinations in Goa, Calangute Beach, the "Queen of Beaches," stretches about 7 km in length.
It's about two times as tall as a Vinson Massif
In other words, 400 shackles is 2.243 times the height of a Vinson Massif, and the height of a Vinson Massif is 0.4458 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 times as tall as a Puncak Jaya
In other words, 400 shackles is 2.247 times the height of a Puncak Jaya, and the height of a Puncak Jaya is 0.445 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 two-fifths as tall as Olympus Mons
In other words, 400 shackles is 0.41 times the height of Olympus Mons, and the height of Olympus Mons is 2.4 times that amount.(a.k.a. Mount Olympus) (Mars)
The tallest mountain in the solar system, Olympus Mons rises to approximately 980 shackles. The mountain has been known to astronomers since the nineteenth century because it is tall enough to rise above Mars' frequent dust storms.