The ship took me by surprise. I had dropped through the shimmering thermocline at 45m, just switched to my bottom mix at 60m, and there it was beneath me. It reclined on its starboard side, its port bridge wing shining in the ambient light, reaching for the surface that it so tragically left some 82 years earlier.
A few metres deeper, and the most incredible sight any wreck diver could wish for emerged. The entire bow section of the worlds largest sunken liner lay before me, sep-arated from the main body of the ship by a vast break just in front of the bridge.
I knew the waters of the Aegean would be clear, but this was ridiculous. It wouldnt be an exaggeration to report that we enjoyed 50m visibility during our first two days- it was like diving through blue air.
Diving HMHS Britannic is how non-divers might imagine a typical wreck dive to be - but never usually is. Its a fulfilled fantasy of a dive.
It was originally to be named Gigantic, yet despite its vastness it actually looks like a ship, and provides a rare thrill for someone used to glimpses of wreckage in the murky depths of the English Channel.
The waters around the wreck dance with great shoals of red Cyprinus ambiguus, more than happy to inhabit the huge artificial reef that the Britannic has become.
The first thing I did was give it a good slap, the same slap of achievement and greeting that I had given the Lusitania on finally reaching it some four years earlier. After years of research, both ships felt like old friends by the time I arrived.

Mystery time
I set off across the foredeck towards the break, and briefly examined the devastation - caused presumably by a combination of the mine that probably sank the vessel and the force of the impact as it hit the sea-bed. Other than this chasm, the Britannic is remarkably intact for its age.
Quite why it is so well preserved is a little puzzling. Low oxygen levels at this depth - it rests in 120m - undoubtedly play their part, though another factor must be the double skin that runs for much of its length, one of the features that distinguish the Britannic from its Olympic Class sisters, Titanic and Olympic.
One of the great mysteries about the Britannic is why it sank so rapidly. After the Titanics demise, the Britannic was improved by adding this double skin and increasing the height of the watertight bulkheads. Yet it sank in just 55 minutes, three times faster than the Titanic.
A wide range of well-documented theories exist, but certainly its second skin didnt help - in a collision, this might have provided some protection, but it was useless against the explosion that sank the ship.

Deco rapture
The array of ropes, poles, weights and tanks that made up our decompression station were in a new, somewhat unproven configuration for this expedition, allowing us the flexibility either to remain on site during our three-to-four-hour hang, or drift free should the current be intolerable. So we kept our bottom times short for the first couple of dives to avoid clocking up a massive decompression penalty that could compound any problems that might arise.
At just 14 minutes total time I began my first ascent, pausing at 84m and 72m for the deepest stops. Such stops have the effect of controlling the early formation of micro-bubbles in the bloodstream, and in this visibility have the significant side-effect of allowing you to continue looking at the wreck, in reality extending the dive.
Scale had been impossible to gauge on my descent, but now I could watch the divers who had followed me down the line still exploring the wreck, mere plankton against the expanse of the Britannics foredeck. I counted 20 sets of their exhaled bubbles rising, then being swept away as the current increased towards the surface.
My euphoria by this stage was such that I was rapidly draining my tanks in a mixture of hysterical laughter and the kind of whoops that should be heard only around the green at the US Open. I think the Americans on the team had infected me by then.
Fixated on the view beneath me as I ascended, I almost backed into Dan Crowell, todays deep support diver, who was there on the line just in sight of the wreck. There were no exhalation bubbles thanks to the closed loop of Dans Atlantis rebreather, but I guessed he was excited because his limbs were moving wildly.
As I got closer, his eyes reminded me of the soucoupe (or saucer) that Jacques Cousteau had used to get around in these very special waters some 22 years previously. Without the luxury of such transport, the pair of us hung there and convulsed with joy for a while at this almost surreal picture. Then we remembered the hours of decompression that awaited us.

Third time lucky
My third dive was the highlight. I had hoped to venture out way beyond the bow and then to film the ship looming up. However, even the 57 per cent helium in our trimix could not prevent an equivalent narcotic air depth of 45m at this depth, and I had a sudden concern that I might turn and miss the wreck!
Not wanting to be the first diver to lose the worlds largest sunken liner in 30m-plus visibility, I turned a little earlier than planned.
Starting at the distinctive anchor crane, still standing upright near the tip of the bow, I flew over the collection of capstans, chains and winches on the Britannics foredeck.
The foremast had broken at its base and now points down to the seabed. A few metres up it I found the crows nest. The lookout would have reached it by climbing up inside the mast and emerging through an oval hole. The guy must have been compact.
There was a distinct absence of a bell here, as was the case in other places where you might expect to find one. How strange!
I zipped over to the captains bridge to inspect the machinery that others had raved about on previous days. Sure enough, hanging by their chains there lay at least four great telegraphs, barely recognisable due to the thick marine growth.
Surely in time the chains will snap and allow these wonderful artefacts to fall to the seabed below - unless, of course, theyre sent in the opposite direction, as it seems the ships bells have been.
No markings were visible on any of the heads of these telegraphs, but careful study of our photographs should relate the positions of the handles to the captains last desperate intentions before he was finally forced to abandon ship.
In the middle of the bridge hung one of the helms, the square spokeholes in its hub the only reminders of where the wheel would have been. Further aft, where the wheelhouse once stood, was the telemotor, still standing perpendicularly to the deck. Again the wheel had rotted away, although the sharp stubs of the spokes were left on this one.
Simon Mills, who owns the Britannic, had asked us to note the colour of the attractive tiles that covered the floor of the bridge. A good sample of this floor-covering still remained around the base of the telemotor. On closer inspection we discovered that it was actually red and white linoleum, not tiles.
The partition between the bridge and the senior officers quarters had also rotted away and in there, just metres from the bridge itself, we found a large metal bath complete with pipework and taps. If only removing the plug could have sluiced away a bit of this water and given us more time on the wreck!
Just time to look at the port running light, still sitting in place on the bridge wing, and then I made for the shotline. It had been an intense 20 minutes. How I longed for more, but every minute I stayed longer than planned translated to an additional 15 minutes of decompression.

Shot away
We had intended to drop a second shotline towards the stern of the wreck after the first week so that we could explore another area. When we arrived for our final dive on the bow shotline, its marker buoy had vanished. Whether acquired by an opportunistic local fisherman, severed by the ferocity of the currents or even by a passing supertankers propellers, that shotline had served us well.
We were equally lucky with its replacement. Geraint Ffoulkes-Jones DGPS installation had allowed us to map accurately the outline of the wreck, so we were able to drop our second grapnel just upstream of the area where the fourth funnel would have been.
It drifted perfectly on to one of the Britannics characteristic giant lifeboat davits. John Yurga expertly tied in this new line, under the watchful lens of photographer Rob Royle, and the two of them eagerly ventured to explore the new territory around them.
The tall davits were another feature that differentiated the Britannic from its sisters. These huge electrically powered cranes could cope with the vessels extra lifeboats and could launch boats even if the ship was listing severely.
They could even take boats from the opposite side if necessary. Their latticework had long since been smothered with a mass of marine growth, lending their towering silhouette a solid impression.
In this new position, we were also an easy ride by scooter or a challenging swim away from the very stern of the ship, so on my fifth dive I made this journey myself, scootering aft along the port gunwale of the wreck, past the second-class accommodation to the stern docking bridge.
The fine framework was intact, but there was no sign of the tele-graphs or helm either on the bridge or on the seabed below it. Captain Cousteau certainly took some polishing home with him back in the late 70s.
I continued aft across the poop deck, the motor of my Aquazepp struggling against the light current and the massive drag of a fully kitted trimix diver, complete with four tanks and a video camera.
At last I hovered over the great sweep of the counter stern. I stopped the scooter and hung there in quiet solitude for a moment, appreciating the scale of the three enormous propellers that powered the 48,158 tons of liner in front of me through the water at 21 knots.
I also thought of the 26 servicemen who were tragically killed when the stern of this mighty ship rose out of the Aegean, its merciless blades slashing their luckless lifeboats to matchwood.
I wondered whether the angle of the Britannics mighty rudder - which was pointing slightly to port - held any significance. Might it have been part of a desperate strategy by Captain Charles Bartlett to beach his sinking ship

No name
I didnt bother to look for the letters of the Britannics name on the stern. John Chattertons extensive efforts to locate the bigger letters on the bow had been in vain. It was the practice of the White Star line to etch the letters only thinly into the plating, and the thick carpet of encrustations that now shrouded the Britannic had made his task too difficult.
On my return, I discovered Derekis Palmeros taking a leisurely and very photogenic saunter along the promenade deck, the ambient light giving him the appearance of being in 30m depth, not 95m.
This whole deck is very open and accessible, and provided the access route for those divers whose mission it was to locate the grand first-class staircase. Finding the correct door to enter wasnt easy, but once inside the first-class entrance we were disappointed to find only a great void where the staircase would have been.

Scooter crazy
Finally, before heading back to the surface, I took a look at the touching plaque in memory of Jacques Cousteau that had been placed on the wreck during the previous years expedition by the members of Kevin Gurrs Project Britannic.
Despite the painstaking safety planning, it was always a relief to get back to the safety of our decompression station. On every dive, we would open the P-valves of our O-Three drysuits and share our relief with the Kea Channel. Two pre-dive, bend-inhibiting litres of Greek mineral water have to go somewhere.
On one unfortunate occasion I shared my relief with my own C-bear undersuit. The guys at O-Three tell me I had been over-ambitious in sheath size selection, but Im just not having it!
Scooters were an undoubted benefit on this wreck, despite the fact that on one dive the propeller of mine tried to eat one of the Scubapro G500 regs that I had stowed clumsily.
Kate Winslet might have thought she was flying up there on the bow of the Titanic, but get yourself clipped on to a four-speed Aquazepp, stick it in top gear, and lap the Britannic - thats flying.
It was a joy and a privilege to witness the majesty of HMHS Britannic like no paying passenger ever did. This is the worlds best wreck and shes beckoning me back. Anybody got a submarine going spare
  • Further information and pictures from this expedition can be found at the teams website: website.lineone.net/~britannic98

  • A liner at war  
    The Great War overtook the Britannic, and it was never used for the purpose for which it was intended. Built as a luxury liner for the White Star line by Harland and Wolff, the Britannic was launched in February 1914 and immediately started work for the Admiralty as a hospital ship, carrying 625 crew and 500 medical staff. Unfortunately, the ship hit a mine laid by the German U-boat U-73 on 21 November 1916, while on route to Salonica to pick up Allied troops wounded in the Gallipoli campaign. There were 26 deaths when the ships lifeboats were drawn into the Britannics rearing propellers as it went down, but all the remaining survivors were picked up.
    Gas menu  
    The bottom gas chosen for the Britannic dives was a heliair (helium plus air) trimix of 9/57 (9 per cent oxygen, 57 per cent helium, 34 per cent nitrogen), giving an Equivalent Nitrogen Depth (END) of 45m and PPO2 of 1.16 on the bottom at 119m.
    The gas was carried in a back-mounted twinset of 15 to 20 litre cylinders. An optimum mix would have contained more oxygen, but would have required the addition of small amounts of oxygen each day, a task that is difficult to do accurately.
    Using heliair made the compressor operators job easier and meant that the divers were always sure of the exact proportions of nitrogen and helium in the mix, even after several dives.
    Air would have had three disadvantages as the first decompression gas:
  • The potential for on-gassing dissolved nitrogen.
  • The narcotic shock at the 60m gas switch.
  • The potential for the very high PPN2 increasing the size of any predominantly helium bubbles already present.
    17/19 Heliair (17 per cent oxygen, 19 per cent helium, 64 per cent nitrogen) was therefore used from 60m to 33m, generally carried in a 12-litre tank on one side, followed by nitrox 40 on the other for use from 30m to 15m.
    These gases were chosen not just for optimum decompression, but to try to keep the usage of each approximately equal so that similar-size tanks could be carried on each side.
    At 12m the side-mounted tank of 17/19 was swapped for another of nitrox 70 that had been staged on the line.
    This was breathed from 12m to 6m and then switched again for pure oxygen for the 3m stop. Every 25 minutes, a five-minute break was taken on nitrox 40 to keep the CNS oxygen toxicity clock down.
    Breathing O2 at 6m would have greatly increased the chance of a convulsion.
  • Divernet