Daryl Morse
Contributor
Since there have been quite a few threads discussing Nitrox courses and the merits of nitrox training dives, Ill provide an opinion based on my experience with the ANDI CSU course which I just finished taking.
For those who dont know, ANDI CSU (Complete SafeAir User) course covers SafeAir (nitrox in ANDI-speak) up to 50% O2, up to two gas mixes and depth to 40m. The use of a sling bottle (redundant breathing supply) is integrated into the course. There are two components to the course, 10-12 hours in the classroom and two training dives. Unlike typical nitrox courses, you WILL learn new skills during the dives. (This course is the prerequisite to the ANDI TSD (Technical SafeAir Diver) course, which covers decompression diving.)
There were two students in my course and the instructor is an ANDI Trimix instructor and a cave diver. (I had completed 41 dives before taking the course.)
The classroom covered a wide range of aspects of SafeAir diving including gas composition, OTU, symptoms of CNS, pulmonary toxicity, and narcosis, depth-pressure conversion, Daltons Law, MOD, EAD, Best Mix, 8 SafeAir applications, O2 clean, O2 compatible, O2 service, cylinder labeling, gas mixing and gas testing. (Obviously we didnt cover everything to the same level of detail.) We did this over two full evenings, but I had spent a lot of time over a two week period going through the entire 130+ page course manual, doing all the exercises and quizzes on my own before I spent any time in the classroom. I had already spent a week going through the instructor manual for the course before that. Both sessions were very interactive and most of the time was spent working on specific problems and questions rather than going page by page through the manual. We also discussed gas management (rock bottom, rule of thirds) and various ways of incorporating a sling bottle and one or two gas mixes into a dive plan.
For the dives, I used a mostly hogarthian setup. The bp/sta/harness was OMS and the wing was a 45 lb OxyCheq. The sling bottle was 40 cf, which I wore on the left side. I used Apeks regulators with a long hose and a bungee necklace. I dove this rig (minus the regulators) a couple of weeks ago to get used to it before the dives for the course. Now that Ive tried this equipment, Im hooked on the bp/w and long hose configuration. Its time to make some equipment purchases
For the first dive, we used 32% back gas and 40% in the sling bottle. We went to 118 fsw. During this dive, we practiced s-drills and gas-switching. The instructor showed us some different methods of donating including bringing the hose over the head while maintaining eye-contact and also ducking the head to more easily clear the hose. We practiced air-sharing off the back gas, then ascended to do the gas switch. We did the switch at around 65 fsw, intentionally well above the MOD @ 1.6 PO2. We practiced air-sharing off the sling bottle, then switched to back gas, stowed the regulator on the sling bottle and ascended.
For the second dive, we used 36% back gas and 40% in the sling bottle. We only went to 90 fsw for this dive, but it was much more active in terms of skills and made even more interesting and challenging by a crazy current due to the large tide swing that day. We did more s-drills on the way down and then did a 5 minute swim to establish numbers for an RMV calculation. We did an air-share from around 80 fsw up to around 40 fsw where we did a gas switch. This was challenging because of the current, but the experience convinced me once and for all of the benefits of the long hose configuration. My buddy and I had to hold on to each other during the gas switch to avoid drifting, due to the current. After the switch, we ascended to 20 fsw where we practiced breathing off the sling bottle while feathering the valve. I was surprised at how little the valve needs to be open to enable breathing. Once we did that, switched to our back gas. At this point, we practiced detaching the sling bottle, handing it to our buddy and reattaching it. Its going to take some practice to get better at this. (Its difficult enough on the surface with no gloves on, let alone with 5mm gloves on and in a strong current.) I had a hard time manipulating the small bolt snaps on my sling bottle harness with my 5mm gloves. I also had a hard time reconnecting the bolt snap on the bottom D ring of the harness. (Where did that D ring go?)
I found it to be an excellent course, by far the most rewarding learning experience Ive had since I started diving last year. For anyone who thinks they may get into decompression diving in the future, I highly recommend taking ANDI CSU rather than a basic nitrox course.
Im sure there are those who question the need for a sling bottle and two gas mixes in no-decompression diving, but the way I look at it, they are tools I can incorporate into my diving as I chose, and I fully intend to do so. By the time I take the next step (e.g., TSD), Ill already be familiar with these tools; Ill just be learning new ways to use them.
For those who dont know, ANDI CSU (Complete SafeAir User) course covers SafeAir (nitrox in ANDI-speak) up to 50% O2, up to two gas mixes and depth to 40m. The use of a sling bottle (redundant breathing supply) is integrated into the course. There are two components to the course, 10-12 hours in the classroom and two training dives. Unlike typical nitrox courses, you WILL learn new skills during the dives. (This course is the prerequisite to the ANDI TSD (Technical SafeAir Diver) course, which covers decompression diving.)
There were two students in my course and the instructor is an ANDI Trimix instructor and a cave diver. (I had completed 41 dives before taking the course.)
The classroom covered a wide range of aspects of SafeAir diving including gas composition, OTU, symptoms of CNS, pulmonary toxicity, and narcosis, depth-pressure conversion, Daltons Law, MOD, EAD, Best Mix, 8 SafeAir applications, O2 clean, O2 compatible, O2 service, cylinder labeling, gas mixing and gas testing. (Obviously we didnt cover everything to the same level of detail.) We did this over two full evenings, but I had spent a lot of time over a two week period going through the entire 130+ page course manual, doing all the exercises and quizzes on my own before I spent any time in the classroom. I had already spent a week going through the instructor manual for the course before that. Both sessions were very interactive and most of the time was spent working on specific problems and questions rather than going page by page through the manual. We also discussed gas management (rock bottom, rule of thirds) and various ways of incorporating a sling bottle and one or two gas mixes into a dive plan.
For the dives, I used a mostly hogarthian setup. The bp/sta/harness was OMS and the wing was a 45 lb OxyCheq. The sling bottle was 40 cf, which I wore on the left side. I used Apeks regulators with a long hose and a bungee necklace. I dove this rig (minus the regulators) a couple of weeks ago to get used to it before the dives for the course. Now that Ive tried this equipment, Im hooked on the bp/w and long hose configuration. Its time to make some equipment purchases
For the first dive, we used 32% back gas and 40% in the sling bottle. We went to 118 fsw. During this dive, we practiced s-drills and gas-switching. The instructor showed us some different methods of donating including bringing the hose over the head while maintaining eye-contact and also ducking the head to more easily clear the hose. We practiced air-sharing off the back gas, then ascended to do the gas switch. We did the switch at around 65 fsw, intentionally well above the MOD @ 1.6 PO2. We practiced air-sharing off the sling bottle, then switched to back gas, stowed the regulator on the sling bottle and ascended.
For the second dive, we used 36% back gas and 40% in the sling bottle. We only went to 90 fsw for this dive, but it was much more active in terms of skills and made even more interesting and challenging by a crazy current due to the large tide swing that day. We did more s-drills on the way down and then did a 5 minute swim to establish numbers for an RMV calculation. We did an air-share from around 80 fsw up to around 40 fsw where we did a gas switch. This was challenging because of the current, but the experience convinced me once and for all of the benefits of the long hose configuration. My buddy and I had to hold on to each other during the gas switch to avoid drifting, due to the current. After the switch, we ascended to 20 fsw where we practiced breathing off the sling bottle while feathering the valve. I was surprised at how little the valve needs to be open to enable breathing. Once we did that, switched to our back gas. At this point, we practiced detaching the sling bottle, handing it to our buddy and reattaching it. Its going to take some practice to get better at this. (Its difficult enough on the surface with no gloves on, let alone with 5mm gloves on and in a strong current.) I had a hard time manipulating the small bolt snaps on my sling bottle harness with my 5mm gloves. I also had a hard time reconnecting the bolt snap on the bottom D ring of the harness. (Where did that D ring go?)
I found it to be an excellent course, by far the most rewarding learning experience Ive had since I started diving last year. For anyone who thinks they may get into decompression diving in the future, I highly recommend taking ANDI CSU rather than a basic nitrox course.
Im sure there are those who question the need for a sling bottle and two gas mixes in no-decompression diving, but the way I look at it, they are tools I can incorporate into my diving as I chose, and I fully intend to do so. By the time I take the next step (e.g., TSD), Ill already be familiar with these tools; Ill just be learning new ways to use them.
