For the Moment, Let's Forget the Diver

PETER DICK explores the origins of surface support, surface-oriented work and diver-surface communications, and their links with the future. This article is reprinted from Issue 22 (Summer 1998) of Historical Diving Times.

Whenever divers are down, out of practical necessity there is someone on the surface to both support them and assure their continued safety. A simple application is a roped diver in the hands of a tender. In the modern era of deep diving, surface support is of the utmost importance and of a sophisticated nature. A Diving Support Vessel (DSV) not only mounts a saturation system and deploys the closed diving bell that divers work from, but also supports all the tasks required of them, some of which are associated with significant feats of underwater engineering.

In the 1830s, 'open' helmet divers were particularly dependent on their safety line, and having their signals promptly interpreted and acted on by the surface tender. Not only did they often require prompt variations in their air supply, but also the signal rope was tied off around the helmet neck, allowing them to be pulled upright again from the surface in an emergency. It seems that a number of early open helmet divers 'fell' over, lost the helmet air volume and drowned. (1)

One doubts if the basic diver-surface relationship was that much different in antiquity. Some may have acted independently, but for most there was a boatman or helper patiently waiting to offer assistance, while the diver below completed his or her task, be it freeing an anchor, collecting pearl oysters, awabi shell fish, or whatever.

Logically then, to the continuing history of diving, there must be a parallel history of surface support. Search the available sources however, and one will be hard put to find any details. Through the ages, if those on the surface were mentioned at all, it was incidental to the diver's exploits. This is understandable, when we consider that most chroniclers had no first hand experience of the practicalities of diving. Then as now, it was a highly emotive subject that conjured up any number of superstitions and stories in the minds of the uninitiated.

The diver-surface link is one that we would therefore do well to explore further, when considering information on diving from any period. Having noted equipment, exploits, depths or times in the usual log book fashion, forget the diver for a moment. Go over things again, from the viewpoint of those on the surface. This is a simple analytical technique, which often helps to explain so much more about what really went on.

To illustrate this, take Oppian, the second century AD Greek poet from Cilicia, and the only ancient source to mention directly those on the surface. This occurs in the fifth book of his Halieutica (on hunting and fishing). His text is particularly important, as it provides the best details we have of the diving technique used by ancient breath-hold 'sponge cutters'. Naturally the narrative contains high drama, which starts underwater but ends on the surface.

"Shaking repeatedly the rope he bids his comrades pull him up. And the mighty sea-monster and the companions of the fisher pull at his body rent in twain, a pitiful sight to see, still yearning for ship and shipmates. And they in sorrow speedily leave to land, weeping over the remains of the unhappy comrade." (2)

Overlay modern experience and we have a window into the past. The diver was on a rope, allowing the tender to feel but not necessarily see what was happening below. Suddenly things began to change as the diver repeated signals to be pulled up. All out anxiety takes over, as the tender literally lost touch with what was happening underwater. For then it quickly became not so much when would the diver surface, but would he still be alive? While the outcome was hopefully not so dramatic, anyone from a diving background who cares to admit it knows the tender's feelings all too well.

It is very easy to imagine that in the past, both distant and more recent, the diver got into the water and carried out a job of work all by himself. Perhaps this was sometimes the case, but there are obvious physical and other limitations on the type of work that can be carried out by a lone diver. Organizing the work so that heavy or complicated tasks were transferred to the surface, clearly began in an era when dive time was limited to how long one breath of air would last. The diver's role was still vital, but it had become more supportive in what is now called surface oriented work.

Take a stuck anchor. Those on the surface could take its weight on the cable, while the diver concentrated his efforts on shaking it free. When the mole at Caesarea was built (21-12 BC), using massive stone blocks lowered into 12 fathoms of water, divers helped in their placement. (3) At Genoa the mole was built using chests of stones lowered from the surface into 10 fathoms, breath-hold divers then going down to check how they had landed and to level the stones.

The key to success in surface-oriented work lay with good diver-surface communications, to co-ordinate properly the tasks that were going on both above and below the water. Enter the signal rope and tender. In the case of the ancient pearl divers, it was a rope around their middle and a helper in a boat. They not only had to dive down, locate oyster shells and fill the bag around their neck, but also to signal the surface in time to be hauled bodily upwards with their catch, within the time allowed by one breath of air.

Later, mechanical devices appeared. In Artillerie, a work by Diego Ufano (1612 AD), who was associated with the Spanish armies in the Netherlands, is an illustration of a method used for salving guns, which had to be recovered after being- undoubtedly lost occasionally when armies crossed rivers. (4) To understand what he was trying to put across, interest must centre on the large screw device shown mounted between two vessels (Fig.1).

For the author, the practicalities of what would have been involved in such a recovery, were brought into focus when an elderly family friend named George Mallin, took one look at the illustration and announced it was the same method he had used in the distant past to raise sunken canal boats. (5) In the way of old professionals, all the details and even the dimensions came tumbling out (he had built everything involved himself), including those on his most notable salvage operation. As he related it, a canal barge sunk in 9m (30-ft) when carrying ballast. No divers here, it was located by sweeping and chains passed fore and aft under the hull. Two lift vessels, linked together by baulks of timber, came over the site and chains were attached to four long screw devices on the surface, of a design similar to Ufano's.

The support nuts had to be of phosphor bronze and continuously lubricated. Steel on steel had been found to seize under load. Apart from this, their worst problems came from the verticality of the screws, because side forces were always trying to move them around. In all, the lift took ten days to complete, before the gunwales were above water and they could begin pumping out. It was obviously a time consuming technique, but one that must have been passed down from earlier generations.

With this in mind, Diego's illustration obviously presents all the important details required to assure a successful gun recovery, beginning with the stability afforded by two vessels. The single screw offered a near vertical lift, although precautions were still required to counter any side forces on the screw, which would try to move the support block across the deck. This is why it could be tied down, and firmly anchored in place by pointed feet pulled into the deck planking under load. It was the kind of visual information easily interpreted by any illiterate gunner with an embarrassing problem on his hands.

More importantly perhaps, the diver only had to secure the rope on the gun and then help with further slinging nearer the surface, should they wish to transfer the load. Yet if we are honest, as divers, at first glance, we are all guilty of initially interpreting Ufano's illustration purely from the diver's viewpoint.

Moving into deeper water, Pedro de Ledesma's Tratado de Pesquerias (1622-1641) showed a general method of salvage, using grapnels to rip the deck from a wreck and get at its cargo. (6) Breath-hold divers assisted by positioning the grapnels then, once the cargo has been exposed, slinging it ready for its recovery. The centrally placed, physically large and heavily geared winch emphasises that the real work was carried out on deck (Fig. 2).

The early eighteenth century saw several salvagers who like George Mallin's forebears worked directly from the surface, in their case using well-developed grapnels and grabs worked by ropes in quite deep water. In modern terms such work is diverless, which brings a new consideration. Surely people worked directly from the surface in antiquity?

Aeneas Tacicus, who wrote the earliest military manual (ca. 358/7BC), raises hopes by mentioning nippers and tongs with names such as crabs, crawfish and lobsters. Unfortunately for the history of diving, these were for use in military operations on land. Like many of the military manuals that followed, he broke off just as he was about to discuss naval matters proper. (7) Our first evidence appears in the Wei Chronicle, a history of the Wei dynasty (220-265 AD), which tells how Japanese Ama gathered seaweed either by diving down, or by working from the surface using metal hooks on the end of long poles.

Mechanical surface-oriented technology first shows up among drawings of various buildings in the notebook of the French architect Villars de Honnecourt (Wilars de Honecourt), (8) which he kept between AD1225 and 1230. He states, "By this machine the heads of piles can be cut off underwater to fix a platform on them."

Well thought out, it was adjustable for varying water depths, with the weight of the saw counterbalanced and so on. More importantly, it carried out a repetitive task, which would have been nearly impossible for a breath-hold diver in a fast flowing river or even still water. Whether or not divers were even considered does not matter. To get the job done, whoever invented the machine realised that working directly from the surface was the only viable option. (Fig. 3)

Our first glimpse of early crude diving helmets, with and without breathing tubes, came over one hundred and sixty years after Villars made his drawing, in Konrad Caesar's work Bellifortis (1393/95-1405 AD). While such equipment certainly evolved to extend a diver's time underwater and help improve work efficiency, these helmets were mostly proposals. They were passed on by way of fashionable treatises and warbooks from one military engineer to another, as ways by which it may be possible to solve an underwater problem should it arise. Military engineers at that time had duties in both war and peacetime.

Admittedly, there were early isolated successes in underwater operations using diving equipment. The early diving bell for instance, was used to great effect at some depth in salvage work on the wreck of the Wasa in the harbour near Stockholm (1663). Even so, the success rate only really began to improve after the civil engineer John Smeaton introduced the first air-supplied diving bell in the second half of the eighteenth century. Thereafter, things changed rapidly, and by the early 1830s the Deanes’ open diving helmet had become successful enough to make diver involvement a cost-effective option, even where small underwater tasks were called for. (9) Even so, it was a time when surface-oriented work still found an application.

In 1838, after other attempts failed, Colonel Charles Pasley was asked to remove the wreck of the William from the river Thames. To help place the gunpowder charges needed, he called on both a dockyard diving bell and the open diving helmet, borrowing two sets for the purpose (one being to the Deanes’ pattern). Strong river currents soon eliminated the bell and, as usually happens when all else has failed, divers (from the Royal Engineers) were called on to finish the job. This came down to screwing two eye bolts into the woodwork so that a pulley system could pull a large charge of gunpowder into place. Unfortunately, conditions were such that one diver got caught up underwater and drowned. Pasley must have been devastated, as indications are that he was very considerate regarding the health and welfare of the men under his command.

Because of this tragedy, when he subsequently moved on to tackle the nearby wreck of the Glenmorgan, he was offered the services of John Ireland, "an underwater man of extraordinary sagacity and skill", who worked from the surface with long poles. Using these he could, "...fix a bolt to the woodwork of a sunken vessel, or attach a chain to an anchor that had lost its cable." This was another underwater skill that had clearly been in place for centuries, though in the eventuality Ireland's contribution was quite limited.

"(He)...sounded or probed with his long poles, and these sounding, or probings, served as a guide to the divers, who placed weights with rings, and lines passing through the rings."(10)

In other words he took some of workload from the divers, allowing them to work more safely and efficiently in dirty water, during a limited window of slack water time. Surface support of this kind is now taken for granted. But then, in Pasley's time, divers were still busily defining their role in underwater work, in direct competition with the more established diving bell, not to mention other underwater-men.

Nowadays, when it comes to choosing the intervention techniques for commercial underwater operations, cost effectiveness is a major consideration. And cost effectiveness itself is a term that obviously encompasses work efficiency. Well beyond the era of breath-hold diving or open helmets, deep diving has now qualified itself into the 500-700m (1640-2300 ft) region, and because of this many deeper subsea oil and gas field developments in the recent past had a maintenance and repair philosophy, based wholly on direct diver intervention. Those developments with a purely diverless philosophy mostly relied on the use of remote operated vehicles (ROVs) of one kind or another with work package attachments. Even so, divers were still available as a back up to sort out problems, should that technology fail. In a way then, it had become the turn of the newer technology to define its role.

In the future, more small or marginal oil and gas fields will undoubtedly be exploited in much deeper open ocean locations, many beyond 1000m (3280 ft). Surface support will take on a new role, working with and controlling the remote systems (11) that will carry out the required work at depth. While some of them will eventually be autonomous, others will remain tethered to the surface, and many will be large and sophisticated enough to carry their own ROV as well as complex multi-functional work packages. Launched from Dynamic Position (DP) vessels on a support cable-service umbilical, these systems will be able to fly and locate a particular bottom site. Then land and dock, to recover and replace production or process modules, weighing maybe 30-50 tonnes or more. They could also carry out pipelines repairs, or routine maintenance and repair jobs in situ. (12)

The future is very much of a challenge, with new technology having first to define a role, qualify, and then try to establish itself in a competitive market. That said, it is still a continuing branch of a long and already well established underwater history. We must also suspect that human intervention will always remain an option at some level. Rightly so, breath-hold divers first defined their role and went on to establish the usefulness of a direct 'hands on' approach many thousands of years ago. (Fig. 4)

References and Notes

1. Although they were said to have fallen, the drownings were more likely caused by the helmet slipping off when they leaned too far forward. See HDS Newsletter, No.14, Dec. 1995, p.16.

2. Oppian, Colluthus, Tryphiodorus, London, 1918, tr. A.W.Mair, V.612-674

3. Josephus, Antiq. Judaic IIb. XV ch.13

4. Diego Ufano, Artillerie, Brussels, 1612, Tract 2, dialogue 24. As divers we are all guilty of viewing Ufano's illustration only from the diver's point of view.

5. George Mallin's family had been operating and building boats on the Grand Union Canal in southern England, at least during in the nineteenth century and probably back to the building of the canal system the previous century.

6. Pedro de Ledesma, Tratado de Pesquerias, Ms.1035

7. See Aeneas on Siegecraft, ed. L.W. Hunter, Oxford, 1927. Flavius Renatus Vegetius (end of 4th century AD) followed Aeneas Tacicus' format, and broke off his war manual just as he was about to discuss naval matters.

8. Villars de Honnecourt, b. Honnecourt, Piccardy ca. 1190. See, Richard Storrs Willis, The Sketchbook of Wilars de Honecourt, London, 1859.

9. Instit.Civ.Eng.Mins of Conversations, vol.2, p.470, 19 February 1833

10. United Service Journal, Sept. 1838, pp.46-47 & Oct.1838, p.273.

11. The term remote system is convenient. Many systems of this type, under a variety of names, are already in use on shallower locations, others for the repair of subsea pipelines in deep water.

12. See D. Appleford, P. Dick, J. Felton, Modularization and Installation, Maintenance and Repair Aspects of GA-SP Technology (OTC 6722), Offshore Technology Conference, Houston, 1991.