She comes into sight when you are 75m down. The first of her deck rails are at 90m, though nearer the bow they are a little deeper. She lies on her starboard side, almost as though sleeping. When you reach the sand of the seabed at 120m and look up, she t


The Britannic weighed 50,000 tonnes, and was 260m long, 29m wide and 18m deep. Today she lies remarkably intact. The divers chose to use the massive port wing telegraph as a reference point, as its white face and markings were clear of growth and easy to see.
The huge ship was built for the White Star line in the Harland and Wolff yards and launched in February, 1914. But she was never to sail as the luxury liner that her owners had in mind.
Before she was completed, she was taken over by the Admiralty for use as a hospital ship, and sailed off to war with 625 crew and 500 doctors, nurses and Royal Army Medical Corps personnel aboard.
On November 21, 1916, as she pushed through the Kea Channel off Athens, heading to Salonica to pick up wounded Allied troops from the Gallipoli campaign, she hit a mine laid only an hour earlier by Kapitanleutnant Siehs in U-73.
So big was the hospital ship that when she sank after 55 minutes, her propellers span high in the air as her shattered bow crashed into the seabed. Twenty-one died - killed when lifeboats were drawn into the whirling propellers - and all the rest were picked up by naval patrol vessels.
Kevin Gurr, who runs the International Association of Nitrox and Technical Divers (IANTD), led the first dive to the huge wreck early last year, and was project leader of the latest three-week expedition.
The aim this time was to make a complete video survey of the wreck, concentrating on the mine damage at the bow. The operation was unique because it used essentially non-commercial sport-diving techniques and diver-propulsion vehicles to conduct the survey. All decompression was carried out in the water, either from tanks carried by the divers or by gases supplied from a boat above.
As the video and still shots were the prime aim of the expedition, the divers used two DPVs equipped with digital cameras to add to the hand-held work with still and video cameras. The DPVs enabled roving teams to film large areas of the wreck that had not been seen since her sinking.
Decompression times were in the order of three to four hours, which could have meant a seven-mile drift in a major shipping lane amid the unpredictable currents that sweep the Kea Channel. So it was decided to use a RIB as a floating decompression platform, with a bar underneath and supply lines to feed the divers with the large volumes of decompression gas they would need. The RIB would be moored to one of the lines attached to the wreck and remain in position for the whole dive.
This did not always work. Sometimes the current became too strong and the boat team had to cut free. When you can feel the prop wash from a tanker, it is either very big or very close. Or both! says Kevin.
Large tuna, looking at first glimpse like sharks, powered through the millions of tiny fish around the massive ship. Other shoals of larger fish obviously call the wreck home, too, and they wheeled in giant circles around the camera lights.
There is clear mine damage to the bow where a gap 20m across appears near the top rail, running down and under the ship, and splitting the keel right through. The divers filmed the break in her side here, and measured this and other bow damage.
At the stern the triple propellors are almost 7m across. The giant rudder is jammed - a consequence of the captains last command to turn the ship around as he tried to head for the nearest harbour on Kea Island.
Those dives seemed to last no more than a few minutes, says Kevin. Then either the rule of thirds on our 11/60 trimix (11 per cent oxygen, 60 per cent helium) or the end of our planned bottom time forced us to leave.
He adds: At about 70m, where we did micro-bubble controlling stops, we felt like tiny specks in the blue. Then at around 60m the first decompression stops would begin. There would be a switch to air at 51m then to nitrox 40 at 30m, and finally to nitrox 80 at 9m. The last three stops were on the deco bars under the RIB at 9.6m and 4.5m.
The Britannic project, involving 40 dives and over 800 minutes at depths in excess of 100m, was an experience suitable only for the dedicated few. Although the team embarked on the project primarily for fun and exploration - it was almost entirely self-funded - it could not be called sport diving. It was the culmination of months of training and years of experience. Kevins own work-up in the year included dives on the Lusitania at 100m, and multiple trimix dives around the UK.
During their last dive on the Britannic, the team placed on her a plaque in memory of Jacques Cousteau, who had been the first to dive the wreck in 1970 using his own experimental trimix gear.
Kevin Gurr can be contacted at Phoenix Diver Training, Poole (tel. 01202 871456; fax 01202 870570). There is a Britannic website at : www.wdi.co.uk/pb/welcome.

Divernet
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The mixed-gas divers of Team Britannic 1997 were: Kevin Gurr, Alan Wright, John Thornton, Dan Burton, Uffe Eriksson, Richard Lundgren, Ingemar Lundgren, Dave Thompson, Alexander Sotiriou and Kerk Kavalaris.