Technical Diving Revisits the Buddy System on the Lusitania

When we conceived the idea of diving the Lusitania, nearly three years ago, there were two main elements to achieving the aim. Firstly, each individual had to learn the necessary mixed gas skills to enable them to make the desired dives with an acceptable level of safety. Secondly, the logistics and systems needed to put ten to twelve of these divers in the water once a day over two weeks to dive to over 300 ft. with all the gases and back up that are required.

In the UK, when we started developing our "technical" skills, there was nowhere to go to be trained. A few experienced individuals could help with advice and one or two US publications that covered mixed gas diving had made their way across the Atlantic. Essentially we had no choice but to accumulate information from these disparate sources and, one step at a time, put it into practice. Today the scene is quite different with a number of well-qualified instructors and centres actively running technical and mixed gas diving courses. Though the British team were mainly self-taught (over many months of disciplined training) they subsequently passed the IANTD mixed gas exams and in the event the entire team (finally!) was made up of IANTD certified Trimix divers.

However, the skills needed to mount an expedition on the scale achieved this past year by the June 1994 Lusitania Expedition are still not taught anywhere. To me this is now one of the most interesting aspects of what we did achieve.

Our team comprised eight British divers and four divers from the East Coast USA. Only I had dived with the US group before and that was for one dive only on the Oil Wreck out of New Jersey - an Air and O2 dive, so we were not really acquainted when the Americans arrived.

Our systems therefore had to be simple and adaptable and we broke them down into two main areas - the in-water decompression system and the gas mixing and filling system.

The level of mixed gas understanding within the team was high - this enabled us to change and adapt what we were doing as the expedition progressed. A good example of this is the choice of gases carried by the team. Initially the UK contigent had opted for two-way decompression, i.e. Nitrox 32 and 100% 02, but after discussion with the Americans we changed to three-way, i.e. Nitrox 50, Nitroc 32 and 100% 02.

Our plan was to put ten divers on the wreck each day that the weather allowed for dives ranging from 90 to 150 minutes. These divers required twin 15L (twin 120cu.ft.) cylinders of Trimix, two 10L cylinders of travel/decompression Nitrox, and one 10L cylinder of 02.

We decided to ship two premixed "quads' of Trimix from the UK to Kinsale in Southern Ireland where we were based. These were a custom blend of 13/52 and comprised thirty two 50L cylinders pumped to 200 bar - enough gas for six days diving and allowing for a number of days being blown out by the weather. We were in fact incredibly lucky and ended up making eight dives each, thereby running out of premixed Trimix and needing to mix it ourselves.

For gas supply and management we had two teams of two people. Myself and Nick Hope ran the Trimix shed and John Chatterton and John Yurga ran the Nitrox side. For Trimix we had two of the premixed quads and two Hasket Gas Booster pumps - an AG 15/30 loaned by Haskel UK and our own AG 75. These were driven by a 125 cu.ft. low pressure roadwork compressor.

Initially we decanted out of the quads and then used the AG 75 to bring the scuba sets up to a high working pressure. The 15/30 was much more effeicient at scalping the low end of the quads when the pressure had dropped; we also used it for filling small emergency oxygen cylinders and Argon ponies for some drysuits. The AG 75 was very useful when we needed to add 10 to 15 bar of 02 to a full Nitrox bottle with a lower than expected PO2.

The two John's had all the Nitrox cylinders delivered by those divers designated as sherpas for this part of the day. They then calculated the amount of 02 and Air needed to be added to bring the cylinder up to the needed working presssure at the correct percentage of oxygen. The cylinders were marked by attaching a strip of tape to the neck, writing the desired fills and then ticking them off and dating it as each part of the process was completed. They were somewhat hampered by the low rate at which the compressor they used pumped and the small banks that the friendly Irish staff only managed to fill occasionally for us during the day.

On the Trimix side, the process took equally as long, mainly due to the sheer volume of gas we needed to pump each day. In practice we found that we arrived back on most days around 2 p.m. and then spent the next six hours filling. Luckily, when we had to switch to mixing Trimix ourselves we had a few divers taking a day out and thereby reducing the amount of filling needed. At that point we had Irish Industrial Gases deliver Helium and compressed Air as well as 02 and mixed a Trimix 12/45 (a simple two way mix needing no added 02).

In the UK, we all mix our own gas and take resonsibility for ourselves that way, but due to our segregated asks in Ireland this was not possible and so Nick and I mixed Trimix for everyone, feeling very aware of the responsibility we were takin for everyone breathing "our" gas at depth and the two John's felt the same filling Nitrox every day.

The gas was analyzed by each diver that night and also the next morning prior to loading the boat. Tables had been cut in advance mostly on MigPlan, though some used DPA and ProPlanner. We found that as knowledge of the wreck increased, the divers gradually increased their bottom times. The bottom time for the 307ft max depth was on average between 20 - 28 minutes for a total dive time of around 120 minutes. (Most divers built conservatism into their schedules.) The harbor was a short drive away from the hotel and dive centre which we had taken over, so each day 10 twin sets of Trimix, 20 side slung Nitrox cylinders, 10 oxygen bottles, plus back up, and air sets for the support divers had to be loaded into the truck and prepared on the slip, then loaded onto the boat fully rigged for departure.

Each set was positioned around the boat in the order that we would enter the ater. The sea around Ireland is tidal and so we had to put all the divers in the water at the same time in order to be able to dive the wreck during slack water. Due to the tide running after it had turned, we also had had to design a system that would allow the divers to decompress without fighting a 2 knot tide for an hour and a half.

During the summer of 1993 we had developed a system that allowed for this. At about 30 meters we attached a lazy shot to a loop in the main down line. This shot could be detached by using a large piston clip. Further up this shot at 6 meters, we had a system of fibre glass poles approximately six feet long divided by extra down lines, each one supported by a buoy. For the Lusitania we extended this system to total six poles, six down lines and seven buoys. On each down line two oxygen cylinders were slung at 6 meters waiting for the ascending divers. The whole system was assembled into units of one pole, buoy, down line and two 02 bottles all in a prepared nylon box and then transported to the site on the main boat's - Sundancer II - support vessel, a 6.5m RIB. One of the two support divers would then put it together in the water while the main divers were on the wreck.

A large slate attached to the clip on the lazy shot at 35 meters was used by the divers to mark who was "down" and who had come "up" the lazy shot to the decompression station. The last diver up could see they were last and so they would detach the shot and the whole system would float away for a stress free decompression drifting with the tide. It is not custom for British or Irish dive boats to anchor into a wreck and so the boats would stand by the decompression station as it drifted. Typically this would be two to rhee miles from the wreck site before the last diver exited the water.

Gas management at depth was relatively easy as due to our depth of over 300 feet any dive beyond a 28 minute bottom time made the decompression requirement so onerous no one wanted to attempt it. This meant that we invariably returned with half bottom mix sets. The side slung cylinders of Nitrox 50 and 32 were the ones most depleted.

With these two systems - gas provision and decompression management - we managed to run a two-week expedition that achieved over 110 dives on the Lusitania totally incident-free. At all times we had a support diver at the surface ready to manage an incident; we had emergency gases prepared for use in the boat or to be deployed in the water to any diver ascending away from the down line. We also had the nearest Irish Naval recompression chamber informed of our plans and on daily stanby - something we believed to be vital.

This type of diving is only possible with complete commitment to the concept of teamwork and total confidence by each member of the team in all the other members. You have to know that the support divers will have your oxygen waiting when you get to 6 meters. When on the wreck you may have another diver with you but essentially you are alone, especially if things start to go wrong. In fact a number of divers made solo dives when their regular partner did not dive. It is during all the surface tasks from leading the van, to filling gas, to checking the luches are ready, to setting up the whole decompression station in the water and preparing it beforehand that "buddy" practices (or pulling your weight for the others) becomes once again relevant.

The Lusitania was for all of us the most amazing wreck dive we have made, but the expedition as a whole was much larger than another wreck dive. It was a deeply satisfying experience of working with a team of excellent calibre individuals to achieve a focused goal, using shared skills and leveraging off each other's strengths.

All of the June '94 Lusitania crew will have a special bond due to this shared experience that we hope to build on in years to come. The British returned to the Lusitania a second time in 1994, but the expedition planned for 1996 will have used the Lusitania and the technology applied this year only as a warm up...!