Published on: Feb 14, 2017

The Stonehenge in the Salisbury plains in England is an ancient monument that has a special significance for the Celtic Druids who are said to be the earliest inhabitants of Britain. It is said that they are the ones who built this amazing structure. Experts such as archaeologists and researchers are still not sure how this structure was built. The largest of the stones at the Stonehenge weighs around 50 tons — and it is a wonder how stones of this size were moved to where they stand today. Apparently some form of cranes were used for the purpose.

Ancient cranes worked on the pulley

Druid legend says that their forefathers levitated the stones to where the Stonehenge stands today but on a more realistic note, the stones actually had to be hauled with the help of sledges, ropes, ramps and levers which is more likely. The question is – how did they do it in an age when there was supposedly nothing quite resembling the crane technology that is available today. Any engineer will tell you how difficult it would be to haul 40-50 ton stones and placing them at a height.

The stone blocks on the exterior of the pyramids of Egypt weigh 3 tons while the largest supporting slabs weigh as much as 70 tons. If this is not big enough, the statues of the Pharaoh Amenhotep III weigh a grand 700 tons each. How did the Egyptians haul that kind of weight nearly 4,000 years ago? To haul a 700 ton load today, a Liebherr Mobile Crane with a capacity of 1,200 metric tons would be required. What crane technology did they have in those days that could lift this kind of load?

Modern cranes operate on oil

The pulley is what helped the ancient cranes function. According to western records, the pulley itself was first innovated in Mesopotamia in 1,500 BC to hoist water. The first compound pulley was made by Archmedes of Syracuse in the 3rd century BC, to haul a warship including its crew. However, the drawback of the pulley came to the forefront as man’s needs for more haulage power increased.

It was in 15th century that Blaise Pascal studied fluid hydrodynamics explaining a new understanding of hydraulic principles like fluid density, pressure, and incompressibility. He invented the hydraulic press, the building block of modern hydraulics

This further led to the development of the hydraulic crane that is today filled with incompressible fluid or oil to be precise. Modern hydraulic cranes can move up to 1,200 tons. It is hard to imagine at present that there’s any load that would ever surpass this limit. But history has made us believe that there is no end to improvement scope. It is an ever ongoing process. So may be our next generation will see a totally different crane!!!