From drawings that have also survived, it appears that the equipment consisted of a metal helmet and breastplate or cuirass, covered from the neck down by a front entry leather diving dress that was held shut by clips. The front of the helmet was moulded in a facial shape, including eyes, which were presumably made of glass. It also had two breathing tubes; the contemporary arrangement being one tube to supply air, the other to allow exhalations to escape. It is not known if any further tests were carried out.
Sieur de Mainville, 1719
A letter from Sieur de Mainville, dated February 16, 1719 addressed to Marshal Destré, Vice-Admiral of France, presented a Mémoire et autres desseins de plongeurs (A memoire on ways of diving) while asking for his protection of equipment proposed by de Mainville. With it were drawings representing what de Mainville saw as two different methods of diving, namely a ‘Free Man’ (l’homme libre) who could move around freely underwater using a self-contained apparatus that enclosed the upper part of the diver’s body, while the ‘Un-Free Man’(l’homme non libre) was to be lowered from a boat on the surface inside a wooden box, much like a coffin with a single porthole.
Operationally, the two systems complemented one another, as the ‘Un-Free Man’ had a purely observational role of assessing the situation on the bottom, followed by the ‘Free Man’ who could both move around and carry out whatever work was required as his arms and legs were free; much freer it was felt than other divers when it came to moving around the bottom. As such, the proposals represented a rapid response system that could be carried on board a ship for use in recovering goods following a shipwreck or, Mainville maintained, to mount an underwater attack on an enemy and scuttle their fleet. Drawings accompanied de Mainville’s letter, as did a list of what he considered necessary to construct the diving system, together with estimated costs.
Estimate of costs for equipping the ‘free man’ diver, prices are in ‘Sous’ and 20 Sous had the equivalent of 1 french Livre which had a value of 1 pound silver.
For the carpenter to make the wooden structure and for the (wood) turner to make the handles for the pumps, 40 sous
Further, for the boilermaker to make the pumps, both suction and expulsion, entirely of copper, 200 sous
Further, for the locksmith to make the ‘turnstiles’ (ballast release and recovery bobbin), the pins, attachments and belts, 200 sous
Further, for the glass panels, 50 sous
Further, for five or six prepared goatskins, 60 sous
Further, for the lead weights, 40 sous
Further, for about 20 pounds of mastic made with new wax, 20 sous
Further, for incidental costs, namely to pay two sailors to arrange four boats in a square and to cover them with a canvas (toile), that 6 trials might be conducted without being seen by anyone, 40 sous
Total 650 sous
Mainville also requested permission to test his equipment in the river Seine near ‘la Samaritain’ (the present-day department store) because, he said, this was the deepest part of the river. Here two sailors had to be paid to position four boats in a square, so that the test-dive site could be surrounded by canvas and not visible to anyone. Unfortunately, history does not record if these trials ever took place.
With the ‘Un-Free Man’ system the diver lay face down in the box looking out of the window, with his hands above his head holding two thin signal ropes. This box was raised and lowered by ropes, pulleys and a twin support derrick system; the recommendation being that there should be three men in the boat. Two of these were to be rowers, while the third attended to diver signals, a bell which gave the signal to raise the diver, while the second signal rope was used to request air. This was presumably pumped down from the surface and distributed inside the box by six curved tubes with ends much like shower-heads.
While the ‘Un-Free Man’ had a purely observational role, the ‘Free Man’ could then follow up and recover what had been sighted. There was a porthole in the wooden box covering the diver’s head, which left the rest of his body free. Four lead ballast weights, shown attached to his legs, could be removed and then raised or lowered using (four) spools attached to his belt to provide the correct weight when making a descent. The breathing system appears to have been intended to work independent of the surface and consisted of four copper pumps, two on the chest for exhaling and two on the back for inhaling, with a reservoir (pouch) between the two sets containing the air supply. In his ‘memoire’, de Mainville also specified that the diver could descend to a depth of 18 feet, for reasons of visibility. It seems that his purpose in designing this second system was to demonstrate what had become a priority – that of a diver being able to move around independently underwater, this making his apparatus a major technological advance at the time. He went on to write that an advance of this magnitude was no trivial thing, as an order of (King) Louis XIV, made at Versailles on 18th July 1703, demanded that young carpenters and caulkers be selected and taught to dive and work underwater. The request for protection for his invention included a further paragraph:
‘Should permission be granted me to retrieve what has been lost in the sea through shipwrecks and other accidents, I should consider myself most ungrateful were I not to present myself to my Lord that you do me the honor of protecting me. The enterprise I propose has to this time been unknown but I beg Monseigneur that if such a discovery has not to be made, the fault lies with men who have always seen it as an impossibility which is far removed from the truth for I can give assurance that it is the simplest thing to be seen.’
Many thanks to Florence Prudhomme for her contribution. Florence is a maritime researcher and trilingual (French, English & German) postgraduate in international relations at the University of La Sorbonne in Paris. She completed a 3-year course in conservation, restoration and preservation of works of art. She is a qualified 3-star CMAS diver with the French equivalent of HSE Scuba (certificat d’aptitude à l’hyperbarie, classe I, mention B) and an advanced Nitrox Diver, qualified at the level of ‘Inspiration Rebreather’. She is presently Secrétaire Générale of ADMAT-FRANCE and a main contact with the French National museums. She also holds the ADMAT (Anglo-Danish Maritime Archaeological Team) Underwater Survey Diver certificate. As well as taking part in a number of ADMAT underwater excavations worldwide, her researches into diving history are mainly a by-product of her maritime archaeological researches in the Archives Nationales, during which she has covered the story of Le Casimir (The Perfume Wreck) and uncovered the epic story of Le Dragon, the last French warship to be lost in the American Revolutionary War in 1783.
