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Getting out of a Sticky Situation August 10, 2019

Posted by Chris Sullivan in Equipment, Technical Diving.
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Having to answer the call of nature during a long technical dive is commonplace. Good hydration is considered important in diving, especially decompression diving, so restricting liquids is not a great idea. When diving in a wet suit, the solution is obvious once you get your mind around it, but dry suits aren’t quite as accommodating.

Back in the day, the solution was adult diapers (a.k.a. “nappies”). Now we have P-Valves. I’ve had one on my dry suit for the last 3 or 4 years and wouldn’t leave home without it. For those unfamiliar with the device, the dry suit will have a valve on the upper inside thigh which can be opened and closed by the diver from the outside. A tube is attached to the valve, with a fitting on the end that goes to a ‘condom catheter’ (for male divers) which takes care of the skin to tube connection. Thankfully this catheter is external, but the downside is that it uses glue to maintain its grip. The catheter need to be applied carefully so as (a) not to entangle hair in the glued inner surface, and (b) to have sufficient area of contact to maintain the integrity of the connection throughout the dive to discourage leaks. A further complication is that the strength of the glue can be inconsistent.

When it works, which is almost all the time, it works beautifully, providing much needed relief to the diver. Once the dive is over, though, the catheter must be removed. The method I learned early on was to wait as long as possible (several hours) to let the glue weaken, and then give it a steady pull until it came off, which meant walking around with it long after the dive. I heard recently of a friend who couldn’t remove his until the following day!

Another friend, an EMT (a.k.a. paramedic), recently gave me some alcohol prep pads and told me that the alcohol would neutralize the glue. The pads were tiny, about 1cm x 2cm and I wondered how such a small amount could work. Well it worked like magic. Working it around the edge in circles gets it off in seconds. I was truly amazed and delighted and now the pads are an essential part of my cold water diving kit.

Lake Simcoe Temperatures July 29, 2018

Posted by Chris Sullivan in Dive Log, Ecology.
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This chart is from Shanty Bay Ontario in 2017 and 2018 showing temperature (in Celsius) vs. Depth (in metres). I’ve only dived there twice this year so most of the graphs are from 2017 running from May until late November. The seasonal variations are quite apparent. In the late spring, the surface is cool at around 14C, warm enough to get students in the shallow water in wet suits. Throughout the summer, the water warms up unevenly, with the bottom remaining quite cold at 7-8C as it warms up very slowly, but the surface gets quite warm and nice in a wet suit down to 10m or so, depending on the suit, the length of the dive and whether you’re wearing a hood.

In mid to late September, the thermocline disappears, and the temperature is more or less independent of depth, as the two horizontal lines depict. Those two dives were relatively shallow so unfortunately I can’t show the effect all the way to the bottom, but from what I’ve read the relatively warmer water extends to the maximum depth of the lake. Also of note is the slightly more than 10C drop between mid September and late November, with the overall lake temperature almost as low as the lowest temperature I’ve recorded at the bottom.

In 2018, on 2 dives 4 weeks apart, the surface has warmed up a full 4C, whilst the bottom has increase a mere 0.2C. The fall seems to be a good time to dive Simcoe, when relative constant temperatures even at depth make excursions to the bottom more pleasant, although somewhat at the expense of the warmer wet suit conditions at the shallower depths. So here’s an update from my earlier chart with more data from last November onward. All temperature data is from my AP Inspiration CCR log.


I’ve also compiled some temperature data for Tobermory wreck diving. Stay tuned.

Lake Simcoe Temperatures January 4, 2018

Posted by Chris Sullivan in CCR.
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As is it the closest body of water to my house I dive in Lake Simcoe relatively often. The drive takes about an hour, compared to 3 to 4 hours to the admittedly much more interesting diving in places like Brockville and Tobermory. While I’ve managed to do both of the latter sites as day trips, it is an arduous proposition compared to going somewhere from which I can get home by lunch time.

Simcoe is relatively shallow, with a maximum depth of about 42 metres and an average depth of 15m over its 725 square kilometre surface area. The deepest spot is the middle of Kempenfelt Bay, quite close to the hamlet of Shanty Bay where we shore dive, so we can get some depth there if we’re prepared for the cold water. As there are few fish, no wrecks, no reefs and nothing much but weeds and silty bottom, aside from looking at what was put there intentionally, garbage thrown overboard by passing boats, flotsam like deck chairs blown in from shore and the occasional golf ball, one can pass the time by doing drills and studying the marine environment.

This latter pastime caused me to stumble of the World Lake Database. The Lake Simcoe information dates from the mid 1980’s, and contains the following table of temperatures by month.

Station K45, 1984 
Depth May Jun Jul Aug Sep Oct
0 4.8 14.8 17.2 22.2 13.7 12.0
5 4.8 14.5 17.3 22.2 14.5 12.0
10 4.8 12.1 15.6 22.2 15.1 12.0
15 4.8 9.3 13.9 15.1 15.2 12.0
20 4.8 7.7 8.5 9.9 10.4 12.0
30 4.7 7.6 8.0 8.1 6.7 12.0

Depth is in metres, temperature in degrees Celsius. Station K45 is in the open water of Lake Simcoe, not in Kempenfelt Bay. There is a station in Kempenfelt – K42 – but so far I’ve not found any similar data from it. The October data looks suspicious with completely uniform temperature down to 30 metres, but I noticed from my own experience that the temperature becomes more uniform in the late summer so perhaps it is the case. 12C is quite a reasonable temperature so there is no reason to hang up the fins just because summer is over.

The chart below summarizes the water temperatures during my dives this year. In July my dry suit failed on a dive in Tobermory, Ontario and so everything after that is in a relatively thin wet suit, with nothing deeper than 20 metres or colder than 12 Celsius (and not for very long at that temperature I can assure you). Even the dry suit dives were curtailed somewhat because my hands were too cold.

You have to look at the chart’s legend to figure out when the dives took place. The ones that start above 20C are in July and August, the and the ones below 15C are from May and June. By the 12th of September, there was little difference in temperature between the surface and 15 metres.

The data were collected on my AP Inspiration EVP rebreather, which records depth, temperature and many other data points every 10 seconds to a precision, although not necessarily an accuracy, of 10 centimetres and 1/10th of a degree Celsius. For each day’s diving all of the data were summarized to the nearest metre by averaging the temperature readings. The result is not a dive profile, but a thermal profile by depth.

Simcoe Dives 2017

So the temperature difference by depth is greatest in the mid-summer months. By September, the temperature at depth is higher than in mid-summer. It is considerably warmer than the September average in 1984, but the dive was only 1 day in September and in a different part of the lake, so it would be hard to draw a conclusion from that difference, although the City of Barrie has published a Climate Change Strategy which indicates that there is warming trend in Kempenfelt Bay based on K42 data.

I’m looking forward to gathering a lot more data in 2018 after the ice melts. The broken dry suit has been replaced with a better one, including a thicker hood and for the first time ever, dry gloves! So next time there should be a lot more data from the depths.

Climbing Back Up the Hill November 11, 2016

Posted by Chris Sullivan in CCR, Emergencies, Fitness and Nutrition.
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Until recently I did not dive enough. I started to forget how much I enjoyed it. In 2015 I only dived a couple of times, and I started to wonder whether I was going to give it up altogether. I also let my weight creep up to almost 190 pounds, putting me just in the “Overweight” category of the Body Mass Index (BMI). I wasn’t exercising. My clothes were too tight.

Fortunately I signed up for a Florida Keys wreck diving trip last April and had a great time. The experience renewed my resolve to get in shape and I then and there decided to bring my weight down below 180. I didn’t have to do a whole lot to make that happen. My diet rules were pretty simple.

  • Avoid bread – not completely but most of the time. I love bread, but now it is more of a treat than a compulsion.
  • Lunches were mostly vegetable smoothies or soup (without bread!). Later, I found a bean salad recipe that I really like, and if I’m at work and haven’t brought anything in I’ll get some take out Sushi or Sashimi.
  • Avoid overeating at any single meal. I can easily wolf down large quantities of pizza. Now I limit to 2 slices.
  • Avoid free food. In our society there are countless opportunities to consume excess calories, like someone bring doughnuts into the office or all-you-can-eat buffets. No longer.

These simple rules worked so well that my weight just kept dropping. By July I was in the mid 170’s, and I was slightly affronted when I attended my physical and my doctor said that my BMI was a bit on the high side at just under 24. Then came the opportunity to conduct a Wreck Diving course in August. That went quite well but I thought I was working too hard even though I’d been getting in better shape working in the garden all Summer. I had to do more exercise.

Meanwhile the weight kept going down. After a long weekend of diving doubles I decided I was going get a CCR (closed circuit rebreather) and felt that there would be a benefit in getting into better shape so I started a simple exercise program. It consists of walking an incline on a treadmill for 30 minutes or so every day, 20 minutes of stretching, and doing some crunches and push-ups every other day. I  walk outside instead of using transit or driving when there’s time. To increase cardiopulmonary capacity the incline will go up by 1% (about 1/2 a MET) each month, so by midsummer 2017 it will be at the treadmill’s maximum. I’m also managing my diet by consuming more protein through food or the addition of protein powder to make up the calories burned by the exercise.

Now I’m down to 160 pounds – way less than I’d planned. BMI is 22, close to the middle of the normal range. There’s still some fat around the midriff but further weight loss is not in the plans. For the next phase I’m going to stay at 160 and try to change body composition with exercise. Despite a normal BMI people call me thin. Is that because we’re used to seeing more overweight people these days, including me 6 months ago?

By staying on the diet the current weight is easy to maintain. If below 160, I add a glass of orange juice to breakfast. That’s worked so far but more might be needed. I’m not stressed about it and avoid fanaticism, but embrace discipline.

Like quitting smoking, the hardest part is deciding. Deciding is not the same as wishing or wanting. The rewards are many, with the greatest being the capacity to keep diving for years to come, greater overall health and better fitting clothes. The flip side is that diving provides much of the motivation to keep exercising – a virtuous circle about which I remind my wife often.

Lastly, I’d like to address a common comment that divers often get from their non-diving friends. It goes something along the lines of why would you do something that can kill you? Often we respond with something like “you can die just crossing the street, if we all thought like that we’d never leave our homes”. While I agree, there’s a more fortuitous response, which is more like “By diving, training to dive and staying in shape to dive, I’m actually increasing my chances for survival. I also hang out with people who are trained in lifesaving and like myself can maintain self-control in emergency situations.”

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).


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.

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.


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.

Shallow Waters May 8, 2016

Posted by Chris Sullivan in Dive Log, Shipwrecks.
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Wednesday turned out to be a disappointment followed by a decent shallow water dive. Once again we were to dive the Duane, and once again the current was way too strong. Like the previous time, we headed over to the Spiegel Grove only to hear of ripping currents there too, so we gave up and the boat took us to the wreck of the Norwegian merchant freighter Benwood, a wreck of a wreck lying in about 35′ feet of water. The Benwood sank after a collision, and then, according to our boat crew, the US Navy used it for target practice , so not only are there a few bombs lying around the site a lot of the metal is twisted beyond recognition. The Wikipedia article on the Benwood states that her stern section “seems to have been mostly obliterated by explosions of an unknown type”.

I dove with Rob, who’d recovered from his cold enough to dive. We took our time examining the wreck. Lots of time, actually, as my total dive time was 120 minutes. Rob logged 115 minutes but I explored for a few minutes below the boat so I could come up with 120 minutes on the computer. My reward was spotting a cluster of 4 lobsters. I’d had the best fill of the week so far so even with the length of the dive I still came up with 1000 PSI in the doubles. We saw a few Rockfish, a spotted drum, and various other more common species, and these mysterious rust coloured fish with big glassy eyes. The boat crew had some opinions on what the fish was, but we didn’t come up with anything definitive.

Any dive is a good dive but this good dive would have been a better dive if it were a dive on the Duane or the Spiegel Grove.


The mysterious red fish is identified as a Glasseye Snapper.


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.

Coming to a Pool Near You May 4, 2016

Posted by Chris Sullivan in Miscellany.
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Everyone likes quadcopters, except when there in the path of the flight you’re on, perhaps, or peering through your bathroom window. Recently though, the “Loon-copter” has been making news from its ability to swim as well as fly. So what’s better than a quadcopter? One that dives as well as floats and flies. Watch the video on YouTube or the web site – very cool, if you can stand the cheesy music. I was hoping with a name like Loon it would be Canadian, but it comes from the Oakland University and it won the United Arab Emirates “Drones for Good” competition. Deservedly so. I wonder what its maximum depth rating is.