Constructed of wood, the fortress crane is operated by a man stepping on a large tread wheel attached to the side of the crane.
What Arkansas construction project is mostly gray but also completely green?
It’s the Ozark Medieval Fortress, a fortified castle built with the tools, techniques and materials of the 13th century, now under construction about midway between Springfield, Mo., and Little Rock, Ark.
The brainchild of Michel Guyot, director of a similar project in Burgundy, France, at the beginning of the decade, the castle will be built using limestone, utilizing blocks of stone weighing from a few pounds to five hundred pounds. The plans call for outer walls to be five feet wide, with each corner protected by a round tower 30 to 70 ft. (9 to 21 m) high topped with a handmade clay tile conical roof. There is to be a drawbridge and the courtyard will feature living quarters, a small chapel and other structures.
To ensure authenticity, a team of experts and historians headed by Christian Corvisier, president of the French Défi Patrimoine (Heritage Challenge) is overseeing the project. The team also includes master builder Pascal Waringo, journeyman trained and a specialist of medieval construction techniques, and Andrew Tallon, co-founder of the month-long Vassar-Columbia Field School in Medieval Architecture held annually in France.
The project began after Solange and Jean-Marc Mirat, a French couple now living in the United States, found Guyot’s Burgundy castle so fascinating they contacted him in the fall of 2008 to offer him a portion of forested land that has all the necessary building materials — water, earth, sand, wood, and stone — for a similar structure while also making the fortress completely “green.” Funding for the job is provided by Ozark Medieval Fortress LLC, a predominantly French organization.
Groundbreaking took place in June 2009. The fortress opened to the public in May 2010, by which time the foundations had been laid. Currently towers are rising overhead, scaffolding has been placed for the next level and stone carvers have been trained to hew dressed stones for the doorways and arrow slits taking shape. In addition, a trebuchet, or medieval siege engine used to hurl large stones from a sling, is being built for eventual display and demonstration.
Almost three dozen craftspersons, predominantly metal workers, masons and carpenters are working on the job, which will take 20 years to complete.
Dressed in appropriate period clothing, while operating under standards laid down by OSHA, craftspersons are constructing the fortress using only medieval technology and equipment as far as possible. For example, bulk materials are moved in horse-drawn wooden carts and all excavation work is done by hand, but OSHA requirements impact construction methods and safety measures.
“For some particular pieces of wood, because regulations state it has to be specifically fastened securely, we use modern bolts and screws. However, we only do what is needed for particular security,” said master stonecutter Franck Falgairette. “All tools made of metal are forged on-site, and will be forged on-site in the future.”
While hand tools and objects such as plumb lines are familiar enough to present-day workers, the crane on site is strikingly different in appearance, while very simple to operate.
“In the French National Library there exists a small book made of parchment and written by a supposed stonecutter or master mason of the time period we are talking about. His name was Villard de Honnecourt. This book of 30 or so folios is a suite of drawings and text,” said Falgairette. “If questions exist about the profession of Villard and his travels between European countries at the time, we cannot question the accuracy of the drawings made and some of the accompanying texts, which are not all written by his hand. And some of these drawings show how we will be using the crane.”
Constructed of wood, the fortress crane is operated by a man stepping on a large tread wheel attached to the side of the crane. Depending on which way the wheel is rotated by its literal manpower, the rope is raised or lowered through its pulley by being wound on or off a spindle attached to the wheel.
“To give you an idea of the size of the crane, you have to understand a man of regular size is able to walk freely inside the “cage,” which is a wheel the diameter of a little more than the height of two men,” Falgairette explained. “So, the boom that is going to carry the load is a little bit longer than the diameter of the cage. Stone being lifted with this device is six to seven times the body weight of a regular person — perhaps more, but we have to think of security.”
An unusual artifact in use at the fortress site is the 13 knot rope, a basic measuring tool with knots separated by twelve equal spaces. It is utilized to form geometric figures such as a triangle, square, rectangle, trapezoid and so on as needed on the job, and also provides the means to carry out addition, multiplication, and similar calculations. It can also be employed in designing arches.
To the modern mind it would be logical to expect a measuring system to be uniform and thus able to be used on any project anywhere, and therefore the 13 knot rope does not seem workable in the context of construction.
However it does not matter, because, as Falgairette explained, this expectation “is a presumption of our time, to have standardized measurement for all buildings built by man, but the coudee and pouce measurements are made to the scale of man and not to the bureaucratic standard.” As an example, he cited an exterior cornice on Chartres Cathedral, where the cornice has to drop a few inches at one corner to connect to its starting point.
“We know for sure that in the thirty years or so building the cathedral, three master masons took turns in the work of building this masterpiece. But we also know that each one had his own personal stick or pige, which is a personal ruler again made at the scale of man. It is not presuming distance and that is the beauty of that period — the human scale,” he concluded.
Visitors to the site are kept a safe distance from the craftspersons, who talk to them as they work.
“This project will become one of the country’s most beloved treasures,” said the Ozark Fortress project’s Julie Sonveau. “It is to become a learning ground for the Middle Ages; an educational center. There are plans for much expansion and interesting projects to bring 13th century history to life for a hands-on experience like no other.” CEG