The Ultimate Gas Dive Weekend

By Mike Boring


When Ken Clayton first talked about using mixed gas to explore wrecks in the 300-400 fsw range a few years ago, I admit I was skeptical. I had a fair amount of deep wreck experience but knew nothing about mixed gas. Quite frankly, the whole idea scared the hell out of me. But as Ken and fellow explorers tallied up an impressive list of wrecks, including the U-140 - 265 fsw, USS Virginia - 360 fsw and the Ostfriesland - 380 fsw just to name a few, I began to rethink my position. I finally joined the technical diving revolution, got some training, and switched to using mixed gas for deep dives. But even then, I was surprised to find myself loading my gear aboard the Miss Lindsey for the deepest push yet, the German Destroyer G-102 - 390 fsw and the German heavy cruiser Frankfurt - 415 fsw.

At 11PM on October 7, 1994 Captain Mike Hillier guided the Miss Lindsey out of Lynnhaven Inlet, into the Atlantic and east towards an area some 60 miles off of the Virginia coast known as the Southern Drill Grounds. The Miss Lindsey, a 60' converted crew boat operated by Lynnhaven Dive Center in Virginia Beach, is comfortably equipped for offshore, overnight expeditions. The divers aboard were Ken Clayton, Brad Sheard, Doug Summerhill, Harvey Storck and myself.

The 5,120 ton, 465' Frankfurt and 1,250 ton, 312' G-102 were two of eight ex-German warships sunk off of the Virginia Capes in 1921. Both were sunk intentionally by aerial bombardment. For the complete story behind these wrecks I recommend Shipwrecks of Virginia by Gary Gentile.

Saturday morning we anchored into the G-102. The sea was calm and there was no current. Capt. Hillier pulled in all the slack anchor line until it was straight up and down. After a leisurely breakfast, we deployed our decent lines and surface supplied oxygen decompression system, suited up, clipped on our assorted stage bottles and clambered over the side into the water. Conditions were so good I felt uneasy, as if I were missing something important.

We were anchored into a steel cable just off of the main wreckage. The bottom conditions were fantastic. Although dark, visibility was 50-75 feet or better. The hull is narrow (the G- 102's beam was only 30') and broken down with no visible superstructure standing. A pair of condensers, one five feet or so higher than the other, may indicate that the wreck is listing slightly to one side. Because of the machinery, I suspect that we were anchored somewhere amidships.

There were a surprising number of fish on the wreck, including what we almost unanimously agreed to be grouper, a species none of us had observed this far north before.

I found a porthole lying loose in the debris between the condensers. Although I had no intention of recovering artifacts at this depth, I was only a couple of minutes into my bottom time and had plenty of gas to fill a small lift bag. I grabbed the porthole by one of the dogs and it broke off in my hand. I grabbed the other dog and it too broke off. Then I picked the whole porthole up and it broke in half. It was made of steel, only the dogs were brass. Apparently, German shipbuilders used their scarce supply of nonferrous metal sparingly.

The wreck seemed to be broken into at least two section. The piece we were anchored in abruptly ended and dissipated into a debris field. There was no discernable bow or stern

Unfortunately, there is little time for extensive exploring at this depth. A cursory examination is the most we could hope to accomplish. Reluctantly, I started back for the anchor line where I would gladly pay for the privilege of this short dive with a lengthy decompression.

Everything had gone so smoothly that we had time to explore a submarine in 235' that had been located on a previous expedition. Because of the shape and configuration of the conning tower, it was thought to be the American submarine Guavina, which was scuttled by the U.S Navy in 1967. Ken discovered later, however, that the Guavina was scuttled further offshore in 7,000 of water. His thinking now is that the sub may be the U-117, which was part of the ex-German flotilla sunk in 1921.

Each of us had only two sets of 120's with mix. We topped off our tanks from the previous dive with air, analyzed the results, and generated our decompression schedules using desk-top decompression software loaded on one of several lap-top computers we had onboard.

The bottom conditions on the sub were less than spectacular and our dives were necessarily brief because of our previous exposure. Unfortunately, we were unable to gather any new data that may help identify the sub. Interestingly though, there were scores of dogfish decorated with a pattern resembling a chain link fence. I saw several that appeared to be trapped in a fish net. Thinking that they were dead, I grabbed one by the tail. To my surprise the creature sprang to life and swam freely through the net. Only to turn around and reinsert itself snugly back into the net, apparently finding some comfort there.

During the last 30 minutes of decompression it was dark. I was entertained by a single squid that was attracted to the boat by a spreader lite that shined into the water. The squid would get almost close enough for me to touch him and then quickly back away beyond my reach.

Unbelievably, Sunday morning brought even better weather than Saturday. The sea was absolutely flat calm and, again, there was no current.

Anchoring into a wreck in 400+ feet of water is no trivial task. Jimbo Davison, Dave Lamontagne and Lindsey Hillier, the Miss Lindsey's mates, definitely got their exercise for the day by pulling up the heavy anchor and hundreds of feet of line several times before we were securely hooked in.

Doug had injured his shoulder on the G-102 dive and wisely decided not to risk a more serious injury by diving the Frankfurt. He asked me to carry his video camera and I gladly obliged.

On the G-102 dive we had a rather relaxed plan, each of us doing our own thing. The Frankfurt, however, seemed to have a different level of intensity right from the beginning. This was going to be a group assault. Our plan was to explore, shoot pictures and video. If time and conditions permitted, Ken wanted to unfurl a National Explorers Club flag on one of the 5.6" guns. The boat was eerily quite as we suited up.

We started down the anchor line in a tight group, separated by only a few feet. Again, the anchor line was almost straight up and down. Ken and Harvey were in the lead, I followed, carrying Doug's video camera, and Brad, an accomplished photographer, was behind me with his housed still camera and attached strobes.

At 50' I switched from EANx 36 to my bottom mix, trimix 10/60.

At 300' we were greeted by one of the Frankfurt's masts, draped with a fish net and floats. The wreck was obviously upright and enormous, towering off of the bottom more than 100 feet. The nets concerned me. The thought of billowing nets overhead in deep, dark water is not particularly comforting. As we continued down it grew darker and darker. At around 340', with my eyes beginning to adjust to the dim light, the giant warship loomed up from below.

At 380', about 10' above the deck, there was a sudden, deafening BOOM! It sounded as if a gun had been fired right next to my head. Thinking that a hose had ruptured, I quickly dropped down to the wreck to gain a more stable position. I rolled over on my back, looking for bubbles, and checked my regulators, gauges and valves. I wasn't losing gas and, except for my heart trying to pound it's way out of my dry suit, everything was intact. Then I saw Doug's camera laying on the deck. Still trembling with fright, I picked it up and was puzzled as to how it could have separated from the locking carabineer I had used to secure it to myself. Then I noticed a hole in the housing the size of my fist. The handle, with the lanyard still attached, was lying a couple of feet away. The sound had been the camera housing imploding. I felt bad about Doug's camera but grateful that it was not a piece of equipment that my next breath depended on. I didn't know it at the time of course, but the sound had been loud enough to give the other team members a scare as well.

Thirty feet away I could see Brad's strobes momentarily silhouette one of the Frankfurt's 5.6" guns as Ken and Harvey illuminated the turret, decking, and superstructure with their powerful cave diving lites. The view was almost surrealistic, like a photograph taken from a deep roving submarine that you would expect to see on National Geographic or the Discovery channel. But I was there, not sitting in my living room watching TV.

I swam along the deck to the turret and gun. The heavily encrusted turret was shaped like a huge wedge of cheese with the point cut off. The gun aimed out into the darkness, never to fire a shot in anger again. Peering over the side of the hull I could see an interesting, broken off section of wreckage lined with railing. I dropped down for a brief look. It looked to me like part of the fantail, because of it's graceful curvature. My digital depth gauge read 403' and I was still 10-15' from the bottom. I remember thinking that this would be perfect for a one atmosphere suit. Providing, of course, that it held up better than Doug's camera housing. I started back towards the anchor line taking note of the nets draped over much of the wreck. The Frankfurt has obviously been a source of aggravation for many fisherman. We were lucky not to have anchored into one and been forced to abort the dive.

Our planned bottom times ranged from 5 to 10 minutes with a decent times ranging from 4-6 minutes. I had planned a 5 minute decent and 8 minute bottom time. At 13 minutes I started up the anchor line, exactly on runtime. I kept looking down at the spectacular site of the Frankfurt until it was no longer in view.

At 200', Ken and Harvey, who had made the dive on heliox, switched to their stage bottles filled with a NEOX mixture of 21% Oxygen and 79% pure neon. According to Ken's calculations, neon is similar enough in characteristics to nitrogen for short exposures that it may be treated as nitrogen for decompression. The advantage is that they were able to switch their first decompression gas while they were still relatively deep because neon, like helium, does not produce narcosis. Switching from gas, particularly heliox, to air deep can inflict a sudden narcosis that is potentially dangerous. The disadvantage to neon, however, is that it is very, very, very expensive. PRAXAIR INC. donated 600cf of 100% neon, which has a commercial value of approximately $2000 ($3.42 per cf), to Ken and Harvey for experimentation. And I thought helium was expensive!

Brad and I made the dive on trimix and switched to EANx 36 at 110'. At 20' we all switched to surface supplied oxygen.

Harvey and Ken used a custom decompression schedule, Brad used a computer program that he wrote which used Buhlmann's algorithm and added "fudge factors", and I used Corey Berggren's Dive Profile Analysis (DPA) program. All of the schedules provided safe decompression with no DCS symptoms.

Someone asked me later if the short dive was worth all the planning, preparation, expense, time and risk. Some things can only be measured by the sense of self gratification attained when meeting a personal challenge. The site of the Frankfurt was nothing short of spectacular and will be forever etched in my memory. I think Brad summed it up best. "It was definitely worth the price of admission."

The Ostfriesland in a 1921 photograph taken by Mitchell's biplane aircraft


Mike Boring and Japanese two man sub in Guam


See Clif Darby's story on the Mitchell wrecks

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