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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.


Trouble in Paradise May 2, 2016

Posted by Chris Sullivan in Dive Log, Equipment.
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The morning dive was a good one. The Spiegel Grove was in fine form, although visibility was less than I’ve seen it previously. I was diving with Joe, who was on a rebreather. Rob had a low battery on his unit and wisely decided to give the day a miss, although I missed having him on the dive. We did a loop around the superstructure and then went into the 95′ deck where there is a mess hall and a workshop with a large lathe and other tools. Unfortunately Joe had a bad cell (giving me ammunition for ongoing but lighthearted arguments on the merits of rebreathers vs. open-circuit technical diving) and we ended the dive earlier than planned with only 4 minutes of deco needed on my part. Joe sat out the second dive so I went in with the recreational divers for my second dive without carrying any deco gas and finished the dive taking Jody for a tour of the same deck as the first dive. Because of a slightly shortened surface interval and a second deep dive I ended up with about 10 minutes of deco, with no 50 mix available to speed it up.

I went up the line at 30 fpm, the maximum recommended amount and started doing my stops. The 30′ stop cleared almost as soon as I got there, and the 20 minute stop was fairly short and I was at 10′ before Jody caught up. I’d seen him hanging below me and found out later he was wondering where I was, but eventually realized that I was above him. Because we were now the last divers in the water, I hurried things up by finishing my deco while swimming to the back of the boat. I’ve often done this just for fun but this time it saved 2 or 3 minutes for both the other divers and crew.

On the downside, I went into the Ocean Divers shop to buy an air fill for my doubles. The woman behind the counter made eye contact and I asked for a fill, at which point she seemed peeved and told me she had to finish some form or other for someone else. I told her I didn’t mind waiting and in a few minutes I was charged $8.60 and given a ticket to take downstairs. I talked to the guy in the air fill station who was helpful enough and gave him my ticket. No claim ticket was given to me, which I thought strange as they had no way of telling it was my tank. He asked me if it would be OK if I picked them up in the morning as he was busy with fills for the charter operation. That was fair enough and I agreed. They opened at 7 so I had time to swing by and grab the tanks on the way to a different operator for the next day’s dive. One difference between Ocean Divers and all the other dive operators in Key Largo is that the others will fill your tanks for free, but there, if you want to bring your own, you pay for the fill.

The next morning we were there at about 7:40 to pick up the tank. The guy I talked to the day before wasn’t there, and the fill station was being staffed by the same person who sold me the fill the day before. She told me that they didn’t get around to filling the tank. When I pointed out that I’d been promised it would be filled by morning, she told me that their policy was 24 hour turnaround. So bizarrely, I had to point out that irrespective of the policy, which had never been revealed to me, a promise is a promise, and the tank should have been filled. She offered to fill the tank right then, so despite this making us late for the boat I had no choice but to let her do it.

She first hooked a Nitrox hose to it, although I’d asked and paid for air. When she was called on this she said that the tank was labelled Nitrox and must be filled with Nitrox, not air. I probably should have taken my tank right there and then but I needed the fill. In rare circumstances her statement is true, when the air station is not O2 clean, but her statement reflected a misunderstanding of the nature of the problem, and certainly shouldn’t be the case at a Nitrox facility. Next she puts two yoke inserts in my DIN valves and hooks two fill hoses to the doubles. At that point I went upstairs for a moment to see if they were a PADI facility (which they are), because we were wondering as instructors whether we were responsible for reporting such faults. We concluded we weren’t. Then while we were talking about it we heard the familiar sound of purging, although these were both repeated and extended blasts of air, not a short single purge as you’d expect.

Mine was the only tank being filled so clearly something else was wrong. Looking in, I noticed she tried to tighten the valve on the left tank in the open position, just as we’d guessed. I pointed this out to her, and while closing it, she told us “the yoke is still not going to come off”. I told her she’d have to purge it first and she snapped “I know what I’m doing”. So I said that we were both certified gas blenders and we were just trying to help – a statement met by silence. Sure enough, with the valve closed and the whip purged, the yoke came right off. I wished her a nice day as we sped out of there, unlikely to return in the foreseeable future.

Mine was not the only case of rudeness, incompetence and egotism (a dangerous combination in diving) at this operation. The other disappointments will be written up by others and I will provide links to them in this blog. I’ve been to other operations on Key Largo that weren’t familiar with technical diving. None of those tried to fake knowledge they didn’t possess. Some might be characterized them as primarily suited for recreational divers so I don’t fault them for not knowing much about technical diving, as long as they don’t pretend to. Faking competence will ultimately lead to something unfortunate, so we won’t be coming back. Some of the other operators told us there has been a lot of staff of staff turnover there, not all of it voluntary.

Fortunately, it was my one and only dive scheduled with them that week.

Another Apeks Quantum Failure September 9, 2012

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My replacement Apeks Quantum failed less than a year after I received it. It’s great that I get a new one but it costs about $60 in shipping and handling each time so it’s getting to be pretty irritating. This time, it decided to start eating batteries. I noticed at the beginning of summer it needed a new battery even though it was only about 6 months old. Then again on last weekend’s dive it was too weak to dive it. I happened to have a brand new replacement with me and used it on the next day’s dive on the Oconto, but on the surface interval it was obviously dying again so I didn’t use it on the Kinghorn later than day and took it to Divetech where they said it could be replaced for another $60.

I think when I get the replacement I’ll sell it to someone who doesn’t read this blog and maybe even spring for the new Shearwater Petrel. That would give me two functionally identical computers and I would no longer need to carry decompression tables.

Apparently the Quantum is made by Seiko, and is also rebranded under several other manufacturers’ names including Dive-Rite, although though don’t seem to carry it any more but have a 3-gas model that looks similar. The Tusa Hunter looks identical, but the Cressi Archimede II is a bit more stylish but recognizably the same design. Cressi always seems to be more stylish if you’re into that –  I’m not – and their motto is “Scuba Diving in Style”.

I’ve reset more bent Quantums (or equivalents) than I can count, usually because the diver using it as a backup computer didn’t figure out how to switch to the deco gas. That happened to me once too. The trick is to hold the left button down for longer than you think is necessary. If you don’t hold it down long enough, it will switch back to your back gas.

The other Quantum trick is that after a reset it goes into metric. If you dive in Imperial units you need to go to the DIVE/GAGE screen and hold the left and right buttons down for 5 or more seconds.

Adjusting the second stage August 8, 2012

Posted by Chris Sullivan in Equipment, Technical Diving.
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My Apeks TX50 second stage came back from service a little too “hot”. It leaked slightly unless the venturi control was screwed at least 1/2 way in. The first thing I did was check the intermediate pressure coming from the 1st stage (an Apeks Black Pearl*). To do this I borrowed a pressure gauge from my local dive shop, immediately noticing that it consisted of a standard workshop pneumatic pressure gauge with a standard 1/4″ fitting fitted with an adapter for a standard inflator hose. I have to find me one of those adapters.

The IP was 130 psi (~9 bar), which is fine. So next I simply unscrewed the 2nd stage from the end of its hose with an 11/16″ wrench and gave it a 1/4 turn clockwise. This stopped the leak, and it breathed fine on the surface, but I observed that the flow when pressing the purge valve was weak. So it back it off an 1/8th of a turn (or maybe a bit more) and then it was perfect.

* Those of you familiar with the Black Pearl might be wondering why I had a TX50 second stage on it. The story started on a recent trip to Tobermory Ontario where I was about to dive the wreck “Forest City” in my doubles. My doubles setup as 2 Apeks Tek 3 regulators with a TX50 second stage as the primary, and an Apeks “Egress” (more about that later) as the backup second stage. When setting up my gear on the boat, I noticed the hissing coming from the TX50 and swapped it with the Black Pearl second stage (like a souped-up TX200) , and haven’t changed it back.

The Egress is a reasonable regulator for it’s purpose. It has no controls – and I’ve compared it to a backup ‘chute. You don’t need (or even want) fancy stuff on something that’s only there to take you to the surface – and I’ve breathed it at deeper than 150’ without undue effort. Having said that, and with some deep diving coming up, I’m planning to use the TX50 as a backup second stage on my tec setup, even though that leaves my poor Black Pearl second stage with two Egresses. The Egress points straight up when mounted on a necklace and invariably free flows when I jump in the water from the dive boat in the Tec gear (it’s fine with my recreational setup where it’s pointed in a different direction). That’s enough to make it less desirable for technical diving where one needs to aim for perfection.

Tidying up the Tec Gear August 4, 2012

Posted by Chris Sullivan in Equipment, Technical Diving.
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Using a dry suit as secondary buoyancy is all the rage  these days, so a single bladder BC is all that’s required. I see the point, but that precludes warm water technical diving in a wet suit. I like to feel the water when I’m in it, and I also move faster in a wet suit, so I’m sticking with my double bladder OMS BC. On the other hand it’s time for some changes, so I’m about to spend a bit of money to make things better. This is the plan.

  1. I’m ditching the oversize OMS “no-sag” pockets. They’re just too large. I could use them to carry weight, two lights, a spare mask, a pocket camera and Jon line, plus a bit more no doubt. The problem is the drag, the difficulty in reaching things, especially with gloves on, and that they would get in the way when attaching stage bottles to the D-Rings. I stopped using them a while back but before I do any serious technical dives I need some stuff to carry the spare parts.
  2. So the first things are cheap, a mask pocket and a Jon line pocket. I’ll see where to put them when I get them but the mask pocket will go on BC belt on the right hand side (I don’t wear a weight belt with a wet suit – no need), and the Jon line I hope I can mount near the tanks. It’s only used at the end of the dive so it can be out of the way most of the time.
  3. Next, it’s time to ditch the lights in pockets. For that, I already have one light that used 3 C cells and is tied to my shoulder strap with a clip and a bungee. The second light, I plan to invest in a wrist mounted self contained unit. I’ve see these up to 1200 lumens which is almost good enough to light up a stadium and no canister is required.
  4. Then, I will buy commercial (Halcyon, most likely) stage bottle rigging instead of the metal units and home made rigs I have now. I’m not convinced that I’ll ever be at risk of being trapped by rigging that can’t be cut with a knife, but having a non-removable ring around the neck of the tank means it has to be drained to be taken off, which has proven to be a pain. The commercial kits are maybe 10-20% better than the home made ones (at least as well as I can make them) in my opinion and I’m willing to pay for that extra 10-20%.
  5. Finally, in Florida last April my reel slipped off my belt, D-ring and all, and by the time I went back to look for it, it was gone. So I’m buying a Light Monkey 400′ reel. It will be a nice upgrade and I have high hopes it will operate more smoothly than the OMS reel it replaces (and much more smoothly that the one I borrowed to penetrate the Spiegel Grove).

More on this when it arrives.

Air Pressure September 27, 2011

Posted by Chris Sullivan in Equipment, Technical Diving.
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Around this time of year I need to blow the water out of my underground sprinkler system so it doesn’t burst during the winter freeze-up. I used to use a company to do it, until figuring out that I could save the money by doing it myself, with a return on investment of 1 year. The process is pretty simple, hook up a regular air-tool compressor to the outside hose bib, shut off the inside tap (lest my toilets explode), crank up the pressure on the compressor to 120psi (safe on my system, your mileage may vary) and program the controller for 1 minute on, 9 minutes off, and cycle it twice.

After finishing on Sunday I disconnected the hose from the compressor without bleeding it off. The hose then whipped around my porch for the next couple of minutes, whacking my ankle (without injury) in the process. This is food for sober thought when thinking about the pressures used in your typical scuba shop, with AL80s at 3000 psi, and compressors that have a safety shut off at 5,000. If a 120 psi hose can whip around menacingly, you can imagine what would happen at 3-5,000 psi.

Most of us learn just how dangerous a scuba tank can be. A recently fatality in Florida is yet another example. Let’s be careful out there!

SDI Comes to Town March 17, 2011

Posted by Chris Sullivan in Equipment, Technical Diving, Training.
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The owner of our LDS has some SDI and TDI instructor certifications, but has been 99.87% PADI for years. He also has some IANTD certifications, but as I wrote long ago I started the IANTD Advanced Nitrox Course, but switched over to PADI Tec Deep mid way through. All my certs except Open Water Diver are PADI, although I did the SDI Solo Diver course but the card is lost in process somewhere.

Today (writing this on March 5, publishing later) Steve Moore from SDI/TDI gave the instructors and some other pro staff a presentation on their courses and standards, and also showed us some of the products he represents from Edge and Hog, which are recreational and technical product lines respectively. These products are aggressively priced and may be a signal of greater competition in the dive industry.

Edge and Hog Wares on Display

Throughout the presentation Steve gave dive shop pricing, but even taking that into consideration the costs were low. A lot of the gear was styled along the same lines as the Apeks equipment that I use, but parts are not interchangeable. The Hog (technical) regulators were similar to the ATX50, although they also had an end port which is handy for us dry suit divers. I use the Tek 3 these days which has all ports between the valves on the doubles and pointing downward so I don’t have to have a weird routing of the dry-suit hose.

He then started the introduction to SDI/TDI. This started with the announcement that Doug Arnberg was no longer the Eastern Canada Regional Manager. No explanation was given. I imagine I’ll hear the story sooner or later.

Pitching SDI/TDI in a PADI Shop

So here as some of the things I heard that make SDI/TDI different from PADI.

  1. In general, fees and materials cost less. This is why Steve was here in the first place. The problem for instructors though is that we are unlikely to give up our PADI memberships so we’ll end up paying for both.
  2. Open Water courses are computer based. All divers have to have a computer, which means the shop has to have them available for rent. The instructors would like them integrated into the console to cut down on losses. That may not happen.
  3. Training curriculum is similar (emphasis on RSTC standards) but is less rigid than PADI.
  4. Except for Open Water training, more than 3 training dives are allowed per student per day, as long as the dive profiles are reasonable. As many training dives occur in quite shallow water, this is quite reasonable and gives greater flexibility to the instructor. Mind you, students will get really tired after the 3rd dive.
  5. Instructor certifications don’t require Instructor Examinations by the agency.

In the end, the decision will come down to the specifics of deal.

I'm Listening, but Still Not Convinced

Recreational Diving with a Shearwater Predator March 7, 2011

Posted by Chris Sullivan in Equipment, Technical Diving.
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My second Apeks Quantum developed a problem last summer. The first one just died, but this one has developed the common problem (that my friends have seen) which is that the depth gauge becomes unreliable. Mine will suddenly jump to 10 feet shallower than I am, beeping mightily about the astronomical ascent rate. So while I’d normally take the Quantum on a trip where the water is warm and clear, with purely recreational dives, I elected to take my tech diving computer, a Shearwater Predator, instead.

The Predator is a great dive computer. Mine used to be a Shearwater Pursuit and was upgraded once the Predator was introduced. The main differences between the two are the OLED colour display (vs. LCD monochrome) and the Bluetooth communications to the (free!) logging program (vs. Infrared). Both features make a big difference to the operation of the computer, especially the nice bright OLED display on someone whose close-up vision isn’t quite as good as it used to be due to Presbyopia.

Predator’s have technical diving features like multiple mixed gases (5 gases for the open circuit version, 5 more for the close-circuit version), flexibility for decompression schedules, underwater gas switches and changes, etc. It lacks features that recreational computers have, especially the audible alerts and the safety stop counter. I don’t mind missing the audible alerts. I’m good at scanning my computer and other gear. Also, I like to guess what I’m going to see before I look at the computer and my air supply, so I develop a good mental picture of my situation.

I use the Predator with a conservative decompression algorithm (GF 30/85, which is actually the default).  The Quantum, at least for the NDL calculation, is less conservative and my diving buddies figure it’s around GF 88/88). The tough guys at in the dive club who use Cochran Computers have them set to about 100/100, by the looks of it. The 30/85 setting means that it will go into mandatory deco stops sooner than most of its recreational counterparts. So unlike the rules that new divers are given, if you use a computer like this you either have to abide by a very short NDL or accept the deco stops.

It’s probably no surprise that I usually do the latter. In the 18 dives I logged in Cozumel I didn’t go past 6 minutes total decompression obligation. Most of the time it was 2-3 minutes, sometimes nothing. It is my belief that a 3 minute 10′ deco stop with a conservative algorithm is more or less equivalent to a safety stop. If miss, the chances of DCS are greater but that’s also true if you miss the safety stop. So in effect, I’m just getting the additional discipline of a safety stop that my computer calls mandatory. Once I’m done the stop(s), I’ll stay a while longer to get some additional safety margin or surface – slowly of course.

Getting well into deco is an entirely different matter. 5 minutes is about all I’ll do with recreational equipment. If I have to escape to the surface I’m probably going to be OK, which is as much as you can say for missing the safety stop on a less conservative computer. Any further pushing of the limits means carrying additional redundancy to make sure that I have the means to complete the decompression under all foreseeable circumstances. That’s why we have technical diving training.

Disclaimer: This is what I do. You need to understand all the facts and risks to make your own decisions about what level of risk is acceptable to you. I certify that this level of risk is acceptable to me at the time of writing, and that’s all.

Log problem on Shearwater Pursuit November 23, 2009

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A very minor problem, but after logging a 2 day dive due to the minor problem reported yesterday, I can’t step through the log (which goes backwards) on the computer to, or past, that “dive”. I hope I’ll fare better with the Shearwater Desktop Software.

New Shearwater Desktop Software November 13, 2009

Posted by Chris Sullivan in Equipment, Technical Diving.
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I just downloaded and installed Version 0.9.9 . I was wondering why it wasn’t released as Version 1, but found out the next day that Version 1 had been released. The first snag I ran into was trying to move the dives from my beta version 0.9.3 to the current version didn’t work.

Reloading worked fine, although dives 1 and 2 are lost as I’d exceeded the maximum of 32. New features appear to be dive export and print. I was disappointed that a double-click on the list of dives doesn’t bring up the details like it did in the beta version. Not sure why that was taken out. You have to go to the menu bar and select “dive graph” to see it.

The Print function is a definite improvement over doing screen grabs like I’ve used in the past for this blog. It puts the graph at the top of the page and the details at the bottom, which I think is a nice layout. I printed one of my dives to PDF for your amusement. One minor nuisance is that you have to save you details before they’ll show up in the print function.

Dive 27

As for the export function I have no real use for it, but it will spit all the data from the log in either csv or xml formats, just in case there’s some useful analysis to perform on it. Here’s a piece of the xml detail.


You can see that I’m in mandatory deco (NoDeco=0) and that I’m breathing EAN71 and the water temperature is 71 degrees Fahrenheit. I’m currently on the 20′ stop at an actual depth of 26′. Some of the information here, like the mix, is recorded in the details but not accessible through the program’s user interface. I would have liked the breathing gases to be recorded. The details allow you to enter the breathing gas (presumably the back gas) manually. The software however is quite useful and is also a free download, so I’m willing to wait for all my favourite features.

There’s also a header record that shows about 25 parameters like the start time, start and end battery voltage, and other things.

An odd thing about the dive list is that when I did my download, dives 34 and 35 were at the top of the list, which 3-33 followed them in numerical order. I’m not sure why, but I wonder whether it’s a reflection of how the dives are stored in the computer. However, clicking once on the dive # column header set them up in their proper order, while clicking again puts them in reverse order.