I’ve moved my blog over to my webpage: www.greatlakestechdiving.com
Please head over there to keep up on my latest articles.
I’ve moved my blog over to my webpage: www.greatlakestechdiving.com
Please head over there to keep up on my latest articles.
This is the time of year that my course schedule for the upcoming summer really begins to gel. The holidays are over, winter has set in, people start thinking about the upcoming dive season and what they would like to accomplish this year. Some divers set their sights on getting additional training and taking their diving to a new level.
Once a person decides to participate in a course with me, the first question is usually “What should I do before class?” Good question, thanks for asking. Let’s talk about class prep a little bit. We can divide it up into four areas: academic, equipment, in-water competency, and administrative items.
Let’s talk about academic preparation. When you think about it, we don’t have a lot of face-to-face time together given the amount, and importance, of material we have to learn. After all, we’re talking about life support training here folks. The work you put in before we meet will only make our time together more beneficial and meaningful. Once a student has enrolled, I get them an eLearning access code or send them the manual, depending on the course. You should complete the eLearning module, or read the manual and complete any workbooks or chapter reviews before class. Make a list of questions you have so you can bring them up in class. Personally, I don’t mind if students e-mail or text questions to me as they read through the material. Preparing well before the class means I don’t have to spend time covering topics you understand, allowing us to spend more time on concepts you may need help with or more time in the water.
Equipment plays a big role in technical diving, especially if you’re just transitioning from recreational diving to technical diving (as in the Adv. Nitrox/Deco Procedures course). I always provide students with a list of required equipment well in advance of the course. You should look it over and make sure you have everything. If you need to buy a new piece of equipment, it’s a good idea to contact the instructor and ask if there are particular brands or models of widget they prefer. It’s no fun to show up to a class with a brand new DecoMaster 3000 dive computer and find out it’s not appropriate for the course. Besides, sometimes if you don’t have a particular piece of equipment, your instructor will let you try some different models to help you make a sound purchasing decision. That was the case when I did my cave diver training years ago. The instructor told us not to buy reels before the class. If we already owned some, he said bring them, use them, see if you like them, but he had just about every size and type of reel you can imagine. We got to try all different kinds, saving us the trouble of buying an unfamiliar piece of kit and only then finding out we didn’t like it.
Have your equipment serviced well before the start of class and make sure everything is in good working order. When you pack for the course dives, make sure you bring all of your gear. Don’t let your course get derailed by the cry of “Oh s**t! I forgot my fins!”
In-water competency, otherwise known as diving, is the most fun part of any scuba course, but can also be the most challenging. What should your competency level be when entering the course? If you can already perform all the course requirements perfectly, then you may not get much out of the course. If on the other hand, your first course dive is also your first dive in a dry suit, first dive in doubles and first dive in cold water, then you’ve been set up to fail. You should have at least some basic competency with the equipment keeping you alive. Practice diving in a dry suit and doubles. Get your buoyancy and trim sorted out. Have your dive buddies watch you and critique you. Better yet, get someone to video you so can see how you look in the water. Try some of the skills required in the course, even if you can’t do them well. You don’t have to show up on day one with all the skills practiced to perfection, but some practice before class will make the course dives a lot more productive.
Lastly, we have administrative items. If you’re enrolled in a technical diving course, you’ve obviously already taken a number of scuba courses and should be familiar with the standard forms used in every scuba course, namely the liability release and the medical information form. I prefer to deal with the liability release on the first day of class, so I don’t ask students to do anything with that prior to our meeting. The medical form, on the other hand, should be dealt with long before the course meets. As you are probably aware, the form lists lots of medical conditions. If any apply to you, you need a physician’s signature on the form in order to participate in the class. As soon as a student signs up for a course, I e-mail the form to them so they have ample time to get an appointment to see their doctor to discuss their medical readiness for the course. It is imperative you show up to the course with a completed (correctly) medical form. If your medical history necessitates you get a doctor’s signature, and you show up without it, you’re out of luck. You cannot participate without a properly completed medical form.
Other paperwork I like to see students bring to class are their log books and photocopies of their c-cards that I can keep for my files. You don’t have to dig up every single c-card you’ve ever gotten. I don’t really need to have copies of your Underwater Pumpkin Carver or Underwater Basket Weaver card, but the main cards like Open Water Diver, Advanced Diver, Rescue Diver, Nitrox Diver, Deep Diver are nice to see.
In closing, let me give a couple final tips. Come to class with an open mind, ready to learn. Also, learning something new can sometimes be stressful, but try to remember to relax. Remaining calm and relaxed will make the skill easier to accomplish and you’ll have a more enjoyable dive. Hopefully, these tips will help you get ready for your course.
That’s the setup for an old joke. It goes something like, “The absent-minded maestro was racing up New York’s Seventh Avenue to a rehearsal when a stranger stopped him. “Pardon me,” he said, “can you tell me how to get to Carnegie Hall?”
“Yes,” answered the maestro breathlessly. “Practice!”
For technical divers, practice is no joke. It may be cliche to say that sharp skills can save your life, but it’s true nonetheless. More importantly, sharp skills may defuse potentially life threatening situations before they escalate.
During training, technical divers are drilled in basic drills like manifold shutdowns, gas sharing, SMB deployment, regulator malfunctions and many others. When you are a student, it’s easy to view these skills as hoops to be jumped through in order to pass the course. The true value of the exercises can be lost. The importance of these drills doesn’t end when you get the certification card. It’s important to maintain competency. The goal is to practice each skill until it can be performed comfortably and easily. When something unexpected pops up during a dive, say a free flowing deco regulator, you should react calmly and automatically. You should react as if you’ve done this a hundred times before because you have done it a hundred times before!
Skills are perishable. Just because you could deploy an SMB perfectly 2 years ago doesn’t mean you can do it today. You have to practice regularly to maintain proficiency and build muscle memory. Now is the perfect time to review your skill set. As the dive season begins, many divers are getting back in the water at local lakes and quarries. Dedicate time on each dive to review and practice. That way, by the time the dive season gets into high gear, you’ll be ready for more challenging open water dives.
The basic tech diving skill set is not only meant to avert life-threatening situations, but also to build confidence. Divers who practice on a regular basis can perform better in the event of an “unplanned event” during a dive. Knowing you can handle most any contingency results in a calmer, more relaxed dive. So as you get back in the water after the winter break, practice your skills, dive safely, and have fun!
Charter season has arrived once again here in the Great Lakes and wreck divers are chafing at the bit to get back out on our favorite boats. Before we pack up and head out, let’s review a few basic courtesies that will make everyone’s trip a little bit happier.
This list is certainly not comprehensive, but it should get you thinking. I’ll bet you can think of many other items to add (just think about what other people do on boats that annoy you).
Have a safe and enjoyable dive season!
Winter is beginning to give way to spring. And with milder weather, thoughts turn to diving. After a few months without a scuba fix, many divers are eager to get back into the water. Lots of divers around here (northwest Ohio) start their dive season in March or April. This time of year, the water is still cold even though we get some nice, warm days topside. The water in our local quarries is currently about 38 degrees (F) from the surface all the way down to the bottom. If you’re getting ready to begin your 2016 dive season, here are a few tips to keep you comfortable.
Stay Dry A good drysuit is absolutely necessary to dive in cold water with any degree of comfort. If your drysuit leaks, you get wet, and wet equals cold. If your suit leaks, find out why and fix it. In addition to the drysuit itself, consider adding dry gloves. I can still remember when I switched from wet gloves to dry gloves years ago. It was a game changer. Having warm hands was the single biggest boost to my diving enjoyment since buying a drysuit. Numb hands completely negate the benefit and enjoyment of a drysuit. While not nearly as popular as dry gloves, it is possible to have your suit fitted with a dry hood as well.
Stay Warm Drysuits keep you dry, not warm. The undergarments you wear under your drysuit keep you warm. If you have not looked at drysuit undergarments in the past few years, you are in for a surprise. Years ago, the philosophy for cold water diving was to wear as thick and heavy an undergarment as possible. Thick and heavy was thought to mean warm. Modern technology has provided us with better insulating fabrics and better ideas. Diving has finally caught up with other cold weather sports in embracing the layering concept. Namely, multiple layers of different types of insulation are more effective than one big, thick undergarment. So instead of wearing your thick “wooly bear” jumpsuit, you may be warmer in a base layer plus one or two other layers. Several manufacturers also make electrically heated undergarments. Some are vests, designed to keep your core warm while others heat the entire undersuit to keep your whole body warm. All of these systems requires batteries to power them. Some batteries go inside your drysuit. Some use external batteries requiring a waterproof connection through your drysuit. If you dive a drysuit but still get chilly, it’s time to check out some of the new undergarments available today.
Argon For years some divers have insisted that using argon to inflate your drysuit will keep you warmer than using air as a suit inflation gas. I think this is one of those practices from the early days of technical diving that sounded like it should work, but was never really tested. The theory is that since argon is denser than air, it is a better insulator, hence keeps you warmer. Argon is dense. It does insulate. But not in your drysuit. There have been several studies and none of them indicate any advantage of using argon in your suit instead of air. An abstract of one such study can be found here.
Adjust your bottom time During the summer months, it’s not unusual to stay underwater a long time, even in cold water, because you know the water closer to the surface is warm. We don’t have that advantage this time of year. The water is cold from top to bottom. You may want to shorten your bottom time and plan to be at your exit point before you get too cold.
Topside Don’t forget to stay warm before and after dives this time of year. Conserve your body heat before dives even if it seems to be a warm spring day. Have warm, dry clothes to put on after the dive to rebuild body heat. Don’t forget your hat and gloves either.
Life Support While it doesn’t necessarily contribute to staying warm, I can’t end our discussion without mentioning your life support equipment. Before jumping into near-freezing water, be sure your regulator is designed to perform well in cold water and visit your local service facility to make sure it’s in good condition.
Summary As Great Lakes divers, we’re used to cold water. But this time, of the year the water may be even colder than we’re used to. But cold water doesn’t mean that diving has to be miserable, as long as you dress for the weather!
In my last article, I discussed the use of personal dive computers and the absolute necessity of carrying some form of back up decompression tables. I referred to the practice of generating decompression tables using software such as V-Planner and then writing the deco schedule in a waterproof notebook. In the past week, I’ve received a couple e-mails asking for more information about this practice. Apparently since the advent of personal dive computers, carrying handwritten back up tables has faded. Here’s my approach. Take it for what it’s worth.
As I noted in the previous article, personal dive computers for technical divers are a fairly recent development. When I got into technical diving in the 90s, the accepted standard was to calculate a decompression schedule for a specific dive using desktop computer software. Back then we used Abyss or Decoplan. Once V-Planner came out (around 1999 I believe), many of us switched to that and have used it ever since. Once a deco schedule was computed, it would be copied by hand into a waterproof notebook. At that time, the gold standard was Richie’s Wetnotes. Since then, many other manufacturers have come out with waterproof notebooks of their own and the term “wetnotes” has become the generic term for any such book (much to Richie’s chagrin I’m sure). The reason these notebooks are waterproof is that the pages are not paper, but thin sheets of plastic. I carry mine in my drysuit thigh pocket.
When developing a dive plan, I start at my computer. I open V-Planner and start running various permutations of my plan. For a Great Lakes wreck dive, I usually know the depth and start with a bottom time of 20 minutes. Then I start fine tuning the variables. What if I use X for bottom gas? What if I use Y for bottom gas instead? How does changing deco gasses affect the plan? What happens when I vary bottom time? This process can be an article or two all by itself. Since we’re talking about how I use a waterproof notebook, let’s fast forward to the point where I have a viable dive plan worked out. I also work out a couple contingency plans. You can go crazy with contingencies. You can make plans for staying longer than expected, shorter than expected, deeper than planned, shallower than planned and plans that account for lost deco gas. You can come up with more contingencies than pages in the book. You have to decide which plans are worth carrying with you. Neatly write the plans you want to take with you in the notebook. I usually write the deco schedule for planned dive, a five minute longer bottom time and a 5 minute shorter bottom time. You, of course, can make as many or as few contingency plans as you like. I write them neatly with a fine Sharpie, clearly identifying depth, time and gas mixes used. I do this because this notebook becomes a permanent catalog of dive plans.
When you write plans in your book, you can use either stop times or run times. Stop times are pretty straightforward: stop at 90 feet for 1 minute, stop at 80 feet for 1 minute, stop at 70 feet for two minutes and so forth. Run times refer to the total elapsed time of the dive. For instance, on the plan pictured above for a 20 minute dive to 190′, I would leave the bottom when my timer reads 20 minutes and make a slow ascent to 90 feet. When my timer reads 24 minutes, I ascend to 80 feet. When my timer reads 25, I ascend to 70 feet and so on. The benefit of run times is that it eliminates the need to do math at your deco stop (looking at your timer, looking at your schedule, adding the stop time to elapsed time). However, for run times to work, you have to be on schedule. You have to leave each level at the proper time. If you leave the bottom at 23 minutes instead of 20, your whole run time schedule is off.
After a couple years of diving, you’ll probably have about every profile you’re likely to need written in that book. It has become your analog dive computer. Even if the dive plan changes, you’re pretty likely to have the appropriate schedule, or something close, in your notebook. I’ve shown up to the boat only to find that our destination has been changed because of weather or some other reason. While others are scrambling to warm up their notebook computer (or tablet, or phone) to cut new tables, I just have to flip through my “analog dive computer” to find the right deco schedule for the new depth.
I’ll admit it. I like planning dives. I like noodling around on V-Planner with different scenarios. I’m also pretty uptight about having back up plans and back up plans for back up plans. I use a personal dive computer on every dive. But I also have my notebook in my pocket with plenty of back up schedules. Maybe carrying a notebook full of dive plans isn’t your style. That’s fine. Just be sure you have adequate redundancy and back ups. Technical diving is all about the odds. I try and stack the odds in my favor on every dive. Dive safely.
Not that long ago, there weren’t any personal dive computers (PDCs) for technical divers. No PDC that could handle multiple gasses. None that could compute a decompression schedule for helium-based gasses like trimix. Back in those dark times, we planned our dives using desktop computer programs like V-Planner, Decoplan, Abyss or something similar. We copied the deco schedules onto slates or into waterproof notebooks (including a few contingency plans). We executed the dives using these tables and a simple bottom timer to track depth and time.
Fast forward to the present. Now we have a choice of high quality, reliable PDCs for technical diving. PDCs that can compute deco schedules using multiple gasses, including trimix and other helium-based mixes. One of the warnings that emerged as technical PDCs gained popularity was that computers make divers lazy and overly dependent on technology. What happens if the computer malfunctions during a dive? The reasonable answer is that using a computer does not eliminate the need for redundancy. Even though we may be carrying a high tech PDC, we still need redundancy in the form of another computer or printed tables.
Unfortunately, it’s too easy to get sloppy and not follow proper procedures. After conducting numerous dives using a PDC, it’s easy to get lulled into a false sense of security. That can be dangerous. It’s usually when we feel safest and invincible that Mr. Murphy pays a call. No matter how reliable your PDC appears, you need to have redundant methods of computing your ascent schedule. You probably still use software like V-Planner to pre-plan your dive. Take the time to write an ascent schedule and a couple contingency plans in your waterproof notebook. Contingencies can include deco schedules for 10′ deeper than planned, a few minutes longer than planned, as well as shallower or shorter than planned. As a last resort, you could even use the good old US Navy Air Deco Tables to figure out a reasonable deco schedule.
It doesn’t matter what your favorite method of redundancy is, just make sure you have some form of backup for your PDC. One of my instructors told me years ago that being safe isn’t hard. We all know what to do. We know the safety procedures and protocols. The hard part is having the discipline to follow those procedures on every single dive. Be disciplined. Don’t enter the water without proper redundancy.