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CCR, O2 Consumption & Exercise October 31, 2016

Posted by Chris Sullivan in CCR, Fitness and Nutrition, Technical Diving.
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With a little less than 12 hours diving a CCR, I’m now venturing to comment on a technical aspect of the experience which dawned on me recently. Surely I’m not the first to think about a CCR in this way, but I’ve not come across this analysis previously and wanted to record my thoughts about it here.

The more I dive the more I concern myself with staying fit, as I’m not getting any younger, and that gets me thinking about both capacity to expend energy and calorie consumption. Rebreather training tells me that when things are going right, bubbles are only released upon ascent, which is just the excess volume from the loop as the gas expands with the decreased ambient pressure. Other than this, all the Oxygen consumed during the dive is metabolized by the diver.

Fitness evaluations are frequently done by measuring inspired Oxygen, and except for what is released on ascent the CCR will measure that based the change in O2 tank pressure. I found this article that directly relates calories burned to O2 consumption and also relates O2 consumption to METS (metabolic units, a measurement of energy used in exercise) and body weight.

I’ll give an example, which for simplicity I’ll use metric units. My CCR has a 2 litre tank, which can be filled to 230 bar. So its capacity is 460 litres. Say I do a 60 minute dive and the pressure in the tank goes from 230 bar to 180 bar, a consumption of 100 litres of Oxygen. Ignoring the bubbles on ascent, I’ve burned 500 calories (100 litres at 5 calories/litre).

I weigh 72.3 Kg right now. 1 MET energy output uses 3.5 ml of O2 per kg of body weight per minute of activity, so if we know our O2 consumption in litres the average number of METs used in the dive will be (litres x 1000) / (body weight x minutes x 3.5). So if it were me doing this dive my average energy expended would have been about 6.6 METs, which is a little less than this source gives for slow cross-country skiing.

Coincidentally, according to the calculator on this site, my current treadmill regime of 3.5 MPH at 6% slope also requires 6.6 METs (BTW tomorrow I increase to 7% slope or 7.1 METs).

Conclusions

So I’m inspired (pardon the pun) to think that this yet another great feature CCR diving. I can now, with reasonable accuracy, determine the calorie expenditure on a dive, and replenish accordingly. I also know how hard I’ve been working on the dive and train to that level.

Regarding the bubbles on ascent, there’s probably reasonable way to estimate how much O2 is going overboard. Fodder for a future post, no doubt.

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Exploring the Eagle May 16, 2016

Posted by Chris Sullivan in Dive Log, Shipwrecks, Technical Diving.
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Once again with Conch Republic, we headed off to the Eagle for the second and final time of the trip (the previous time we went there after deciding not to dive the Duane due to current). Joe and Rob were on their rebreathers with me on my doubles. Descent was uneventful and as usual I deposited my deco tank in a crevice on the wreck near the stern descent line.

Joe led the dive. We headed for the top of the superstructure on the stern, entering the wreck on the starboard side which was near the ocean bottom. We entered a non-descript room and Joe headed through a doorway, but unfortunately left a fair amount of silt behind. Unwilling to enter in zero visibility, I waited, illuminating the doorway with my dive light in case Joe was having any difficulty finding his way out. Within a minute he reappeared and we headed in a different direction exiting the forward end of the superstructure.

There we saw a Goliath Grouper just inside the wreck. There were some divers about 10′ above us and I tried to get their attention so they could take a look at him, but none looked in our direction. We then started wondering where Rob had gotten to so we went back to where we entered the superstructure then back to the line to look for him. We saw him 30′ or so above us signalling “OK” with his dive light, finding out later that he lost most of his diluent supply getting through the first door and decided to bail out. I’m glad we saw him and didn’t have to search the inside the of the wreck.

Atlantic Goliath Grouper

                                            It was bigger than this one

After doing a lap around the bow section, we returned to the stern and slid back in near the prop. You have to get low to the bottom to do this, and the interior is prone to silt so good wreck penetration skills are needed. 2 years ago we were swimming through the same spot and it started to silt up, prompting me to quickly exit the way I went in. This time was much better and we went sideways through a hatch (or maybe just a hole) into the very bottom of the ship, where there were reassuringly several large exits, although not much else to see. After this we went back to the line and ascended – and as usual Joe was finished his deco about 3x quicker than me.

Once more to the Spiegel Grove May 13, 2016

Posted by Chris Sullivan in Dive Log, Shipwrecks, Technical Diving.
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The last deep dive of the week was once again on the Spiegel Grove. Did I want to dive the same wreck 3 times in a week? Hell yes. I love that dive. This time four of us, Rob, Jody, Joe and me all together exploring levels 1 and 2. Level 2 is perhaps the more interesting one as it has the mess hall and the workshop, which has a grinder, planer, drill presses, lathe, hoists, workbenches and welding equipment. No-one seemed to have much trouble getting through the doors this time and we didn’t have any bailouts.

Near the end of the dive we were in the workshop when through a doorway we saw a large (no, like, really really big) Goliath Grouper hanging out. We watched him for quite a while but he eventually swam away slowly. We followed after him, descending through an oval hole and under the deck that overhangs the dry dock area. It looks from the plans like the hole once housed some kind of smokestack, but in (not 20/20) hindsight I’m a little fuzzy on which deck some things were on. The plans don’t show the stack on the workshop deck. It looks like once through the hold we swam out from under the deck on which the 3″/50mm guns used to be mounted, just before getting to the 50 ton cranes.

To be honest even though I surface with the feeling I was really getting to know the layout of the decks, in retrospect I’m not entirely sure what was on each deck, except for the mess hall and the machine shop. When I look at the plans I can’t reconcile everything with what I remember. Maybe narcosis is factor, or maybe the ship was reconfigured after the plans were drawn.

We also came upon the “Top Dog” floor mural in one of the hallways in the approximate centre of the deck, which I’d not seen before. It’s easy to overlook, being in a nondescript hallway running across the deck, and partially covered in silt.

TOP DOG - USS SPIEGEL GROVE (Floor Mural)

That was the best dive of the week, although I really like to go into the below decks again where it’s necessary to run guidelines. I’ll have to wait for my team members to get a little more time and confidence on their rebreathers before doing that again.

Day of the Eagle May 7, 2016

Posted by Chris Sullivan in Dive Log, Shipwrecks, Technical Diving.
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For dive #3, Rob was down with a cold and Joe was still waiting for his O2 sensors to arrive. Jody had arranged to do his final dive of the rebreather course with the Gary, owner of Conch Republic, so I arranged to dive with them. This time we were on the Eagle. It was a fine day (like all of them) and current was minimal when we tied off on the stern line. When we’d descended to the wreck I put my 3/4 full deco tank (50% 02 in a 45 cubic foot steel tank) on the wreck right next to line. I recalled when diving the same wreck a few years before with Matt we’d initially staged on the bottom and as we swam away I realized that 115′ wasn’t the best depth for them, so we’d gone back and put them near the line and 30′ or so higher – saving us from descending again near the end of the dive.

Mindful of their near optimal O2 mix and effective gas capacity, I stayed about 10′ above them for most of the dive. I followed behind most of the time with Gary leading the way. We went inside the superstructure on the stern section for a bit but it was difficult for Jody to maneuver easily in the sideways wreck with his new kit. We also toured bow section, separated from the stern by Hurricane Georges in 1998, going round the bow from deck to hull then through a hole about half way day back to the deck. At one point I helped Jody get through a swim through which was giving him trouble because of the position of the bail-out tank. I just lifted it and he went right through. Then, of course, I had to make a point of sailing through without any contact, just to show myself that I could in my doubles, as no-one else was watching.

By the time we got back to the stern line I had 18 minutes TTS (time to surface) so I waved goodbye and went up to my first deco stop. By the time Gary and Jody came up I was nearly finished my deco and when I was done, I went back on the air in my doubles and hung out with them near the line while they finished theirs. I only had 100 PSI of 50% Nitrox deco gas left at that point, which was about 4 minutes worth, but at least an hour of air as a contingency in case I had run short.

While I love the Spiegel Grove for its sheer scale and upright position, the Eagle is a cool dive, especially once you get to know your way around it.

Decompression Period May 3, 2016

Posted by Chris Sullivan in Dive Log, Equipment, Shipwrecks, Technical Diving.
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Dive #2 was supposed to be on the Duane. It’s not my favourite wreck down there, and I’ve often said I could dive the Spiegel Grove every day of the week, but I’d never turn down a dive on the Duane. This time, though, when the Conch Republic boat got there, the buoys marking the site were under water, meaning very strong currents were present. I’ve dived the Duane in conditions like that and we had been surprised no-one had been swept off the wreck, so discretion prevailed and we headed off to Dive the Spiegel Grove again, which, of course, I didn’t mind one bit.

There was a fairly strong current on the Spiegel Grove as well. I was feeling slightly queasy after the long ride, but when I got to the back of the boat I was asked to wait as Rob was still getting ready. I sat down and didn’t feel to good so I told the crew I’d wait in the water and went in. It took some hauling to pull myself through the current to the descent line so I used the waiting time catching my breath using the atmosphere instead of my tank. Even so I used 400psi (about 28 cubic feet) just getting down to the bottom of the line, although some of that might have been lost due to the change in temperature. Using water temp of 27 and air temp of 33 the change in pressure due to temperature would be equivalent to about 6 cubic feet.

I was with my trusty buddy Rob. He was on his new rebreather so we didn’t push too hard – doing the swim throughs on the first and second levels above the main deck – and after reading some of the APD Inspiration manual I’m sure he had plenty enough to think about. Even though we were to dive the Spiegel Grove no less than 3 times during the week, we never penetrated the wreck below the main deck, where we need to run lines, choosing to stay conservative. In previous years we’ve gone one level below the deck and I was hoping to go further this year but it was not to be.

Rob’s kit wasn’t as streamlined as his doubles because his bail-out tank was not as parallel to his body as we tend to have with our doubles, and at one point he had to extricate himself from apparently entangling some of the many hoses on his kit while going through one of the doorways on the wreck.

As usual I racked up a bunch of deco time. Rob had very little, so this dive goes to the rebreather for minimizing hang time, although marks were deducted for the hangup in the doorway. Mind you, we were entertained by a group of Barracudas which circled us on each stop and the water was warm, although it would be been more fun to spend that time on the wreck.

Conch Republic handled everything wonderfully. Their setup on the dock is easy to use with the nearby fill station (although Mark carried my doubles to the fill station that day), hoses, hangers and dunk tanks.

Changing Attitudes to Deep Air September 13, 2012

Posted by Chris Sullivan in Technical Diving.
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Some day I’ll get trimix certified. I’ll probably try it out before I do so (if that’s shocking remember that someone had to be the first to try recreational trimix, and they certainly weren’t certified for it). When diving the Jodrey recently we discussed using normoxic trimix instead of air. We didn’t end up doing it, partly because not everyone could reasonably put up the money for a $150 fill. Still, as the owner of Dive Tech said, “it’s like diving two different wrecks” and as I push to greater depths I’m starting to cross what is a very fuzzy line between what is reasonable and what is not. Perhaps I’m already past it. I think that the narco stop concept has reduced some of the risks, but I still know that my reactions are slowed by the onset of narcosis.

I came across an abstract of a paper in the Rubicon Foundation archive a couple of days ago and I thought I’d repost it here. It has the catchy title: CLINICAL EVALUATION OF REPETITIVE DEEP DIVING BY RECREATIONAL DIVERS ON THE WRECK OF THE ANDREA DORIA. It seems to say that the divers in the study were just fine diving air at greater than 200′. The emphasis on the comment about narcosis is mine.

Ten male recreational divers were clinically evaluated over a 3 day period as they made repetitive deep dives [> 200 fsw) with compressed air to the wreck of the Andrea Doria in the North Atlantic Ocean. Diving profiles were recorded and verified while divers were followed clinically for signs/symptoms of decompression sickness, air embolism, and/or other diving maladies. Ultrasonic Doppler testing was used to assist in objective analysis. The divers ranged in age from 27 to 47 years old, weight from 145 to 285 lbs., previous logged dives from 50 to 1250, and diving depth from 187 to 240 fsw. During the 3 day study period the ten divers performed a total of 49 dives. None of the divers exhibited any signs/symptoms of decompression sickness or air embolism. Intravascular bubbling was detected in only 2 divers and only one diver attained a Spencer rating of 2 on any dives. The incidence of positive Doppler testing was 4.3%. Nitrogen narcosis was not a significant problem for any diver. The equipment used by each diver was extensive and included multiple back-up devices and systems. Eight divers carried at least 1 dive computer, while 1 carried 3 (in case the other 2 failed). With the water temperature at depth of 46 degrees F., all divers wore drysuits, except 1. All the divers had trained for these deep dives by performing progressively deeper dives [ > 130 fsw] several weeks to months prior to attempting these truly deep dives. Although not recommended for the average diver, repetitive deep diving by experienced recreational divers, with appropriate equipment and training, led to no incidence of decompression sickness, air embolism, or other diving maladies during this study.

Florida Keys 2011 – Vandenberg September 11, 2012

Posted by Chris Sullivan in Dive Log, Technical Diving.
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This is a continuation of the trip I took in April 2011 to dive in the Florida Keys, and I’d written most of this then but decided to finish it now. Like many bloggers the urge comes and goes. I’ve left this alone for quite a while. I left off with a dive on the Spiegel Grove, but Matt and I chartered that separately, which was great because we ended up diving the wreck 3 times during the trip.

The first official dive of the trip was on the Vandenberg off Key West. We used a different dive shop, Sub Tropic this time and they were more conveniently located for parking than the previous year’s operator and a very short distance to the dive boat. The dive boat itself was reasonably well suited for those of us diving doubles.

It was a fairly rough ride out to the wreck and several divers were sick, although fortunately I wasn’t one of them. When we got there, Matt and I agreed that we would run a similar profile using our computer maxing out at either 1 hour bottom time or 30 minutes deco time, using EAN50 as our deco gas and air as our back gas. This turned out to be our standard profile for the remainder of the week, sometimes modified slightly to accommodate the various depths.

The wreck is a lot of fun where you get to swim around the big satellite dishes (and even through the hole in the focal point of one of them) as well (assuming you’re trained and equipped) lots of easy penetrations through the hallways.

The staff were among the most helpful I’ve ever seen and well-deserved the tips we gave them. The dive shop has now closed, though, but a different one has taken it over.

One thing I’ll never forget is on the ride back from the wreck we passed a Naval vessel moored near the residences for married sailors. One guy on the boat who lived there was a chief nurse who had done some rotations through Kandahar, Afghanistan, describing it as “the worst place on earth”. It made an impression.

Tech Diving Mag September 7, 2012

Posted by Chris Sullivan in Diving Books and Films, Technical Diving.
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I found some interesting articles in this free on-line magazine. It’s worth a look (thanks go out to my dive team member Rob for the pointer). There are 8 issues so far. The articles are contributed by the readers and are of excellent quality. Issue 8 has articles about decompression sickness and treatment, margin for error in decompression tables, solo cave diving, cave diving in the Dominican Republic, and an interview with Dick Bonin, founder of Scubapro. I haven’t read the others yet, so they will make for some good reading on my commute to and from work (don’t worry, I go by train).

Diving the Roy A. Jodrey September 6, 2012

Posted by Chris Sullivan in Dive Log, Shipwrecks, Technical Diving.
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I once described this as my “Pinnacle Wreck”. I’m going to have to change that designation to the either the Andrea Doria or the HMCS Canada, which are both at 200’ +, although there are definitely more visits to the Jodrey in my plans for the future – maybe even in the next few weeks.

Monday September 3rd was another perfect day to end a perfect Labour Day weekend, with morning coming without a cloud in the sky. We set out from the Caiger’s Motel dock, just a few minutes east of Rockport, Ontario, with Captain Mike at the helm and the same divers as the day before. However this time we planned to move the recreational divers to another boat after clearing customs. We did this so the boat manifests wouldn’t have to be changed at the last minute to give US Customs one less thing to worry about.

US entry took about 15 minutes, mostly because the other boat was slow. It was also right about then I realized I’d left the keys in the Highlander which was parked back and Caiger’s, but I had to put that out of my mind. We had the same agent as the day before, known to me only by his name tag (“Rufa”), who I’d also seen on trips in other years.  He had seen all of us the previous day and actually smiled, and noting we were planning to dive the Jodrey, encouraged us to return to Canada alive. After discharging the recreational divers it was a short chug upriver to get to the dive site, right next to the US Coast Guard station. The others went in the opposite direction to the Keystorm and America.

The weather was very calm, and we took our time getting ready, going over the plan, some emergency procedures (one to Mike, “if you see an SMB while we are on deco, drop this tank in the water for us”), and after entering the water assembled near the shore to sort ourselves out and rest (if you’ve ever climbed out of a dive boat with doubles and stage bottles on, you’ll know why we rest). With Brad in front and me out the back following Matt and Rob, we headed toward the channel and hopefully finding the ship this time.

We headed diagonally from the entry point toward the centre of the channel and slightly downriver. It dips into a sort of a bowl at around 30′ before turning into a steep wall. As with the day before, we stopped at various intervals on the descent to rest, regroup and keep our heads clear.  There was a mild upward current as we went over each ledge, which added to the descent time a little, but the  worked well and we were in good shape by the time we reached 150′ and started moving with the wall to our left hoping to see the wreck. By the time the bow end of the wreck slowly became distinguishable from the rocks in the gloom, we were at 175′.

Rob stuck close to the wall and I noticed that was going into a confined area between the ship and the wall. Like the previous day’s dive on the Oconto, as I started signalling with my light he noticed what he was doing and turned around. We examined various stairways and holds and in one section, where I realized that it was well lit and open, I decided to go for the maximum planned depth of 190′ and started a slow descent. At this point, Brad signalled for everyone to leave. We were only 15 minutes into the dive and everyone wondered why, but it turned out to be a miscommunication between Rob and Brad over the amount of air he had left. Better safe than sorry so I had to be satisfied with 185′, which I must say is plenty.

It will take a few more visits to really get a feel for the wreck. Now that I’ve been there once I can be less concerned about the execution of the dive and spend more of it actually checking it out. Of course, I’d no doubt remember more of it if I’d used Trimix. I must take that course some time.

Despite the abbreviated bottom time, we were thrilled to have finally added the Jodrey to our log books, and really had a great time recounting the dive on the trip back. My Highlander was still there when I got back, the drive home took only 3 1/2 hours even in the long weekend traffic (It sometimes takes more than 5), and my wife had cooked me a lovely dinner. All in all a perfect end to a perfect weekend.

The Healthful Effects of Deep Diving September 5, 2012

Posted by Chris Sullivan in Fitness and Nutrition, Technical Diving.
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Maybe just diving in general. Mind you, I’m speaking subjectively with a sample size of one, so statistically this means absolutely nothing.

In the days leading up to last weekend’s diving, I was wondering if I was starting to get too old for the technical diving I’m doing. I’ve had issues with a torn meniscus (makes my knee a little stiff), and some days I get up and don’t feel 100%. When I left for Brockville on Saturday morning I felt OK, but I was a little edgy, and wondered if I should be diving at all, especially the 170′ fast current drift dive in dark water with limited visibility.

I’m glad I did. When I got out of the water I felt great and still feel great writing this today. What I really needed was a good dose of Adrenalin and Nitrogen Narcosis to shake off the stress of my life on the earth’s surface.