Journal of my new PADI course

[XS-NRG]

XS-NRG,

This is an excellent account of PADI OW. You seem to be noting a lot of the details. Your instructor sounds quite good and thorough as well.

Glad you like it :cool2: Yes the instructor is pretty good. She's been doing this for 30 years and is a Master Scuba Diver Trainer

You are absolutely correct. This just re-enforces my point that PADI gives instructors some freedom for how they structure their training.

As it should. Flexibility is key as teaching and training can always get off topic or go on a side tangent very easily as the students give input. If a teacher can deliver the same material in a more efficient way then it really does maximize the use of everyone's time.

Just got back from my final 2 dives in the freezing cold Waterton Lakes (well only 8 degrees C). Had a blast, will do a write up tomorrow though.

 

[scubadiver888]

Once I managed to get a handle on this I had quite a good time swimming in a line with all the others as we finally make it through the silt cloud and followed the natural contours of the lake bottom. Before long 26 minutes had passed and a max depth of 26 ft was made (according to my computer) and it was time to surface.

Our first dive was great and most of us didn't want to get out, but as soon as we surfaced and felt the air outside on our wet bodies we certainly wanted to get out a bit more quickly. Before doing anything else we headed into the camp kitchen (where there was a fire already going) and dried off. We went over what happened, what we did wrong, what we did right and then logged our dive. We started as a "B" diver, ended as an "I" diver and then sat for 1:30. This dive was a shore dive in freshwater and I had 30lbs of weight on. In 26 minutes I went from 2700 PSI to 1500 PSI. For that depth I'm probably still an air hog.

I don't think you are an air hog. For a new diver I think you have pretty good air consumption. The amount of air really needs to be measured in cubic feet or litres. One PSI in an Aluminium 80 tank is not the same amount of air as one PSI from a steel 90.

Here is a little math, for the nerdy people this will be interesting. For the rest of you I'll summarize at the end...

An Aluminium 80 with 3000 PSI at a certain temperature (I think it is 20C or 68F but I might be wrong) is actually 77.4 cubic feet of air (I have no idea why it isn't 80 cubic feet). If you take 77.4 / 3000 you get 0.0258 cubic feet per PSI. If you use 2700 - 1500 or 1200 PSI you used 30.96 cubic feet of air in 26 minutes. If we normalize this to 1 minute you have 1.2 cubic feet of air per minute. Here is the hard part. If you never went underwater, this would be 1.2 at 1 atmosphere. The deeper you go in the water the faster you breathe air. At 33 feet you breathe twice as fast. At 66 feet you breathe three times as fast. Your maximum depth was 26 feet. If we take (max depth / 33) + 1 you get the multiplier. If you had a square profile, that is down to 26 feet, stay there for the entire dive, go back to the surface then you were breathing air at (26 / 33) + 1 or 1.8 atmospheres. So one breathe at 26 feet would be 1.8 times more air than at the surface. If you breathe 1.2 cubic feet of air per minute at 26 feet, you breathe 1.2 / 1.8 or 0.67 cubic feet of air at the surface. A Surface Air Consumption (SAC) rate of 0.67 is very good for your first dive. Some people never have a SAC rate this good. HOWEVER, if you were sometimes at 26 feet, some times at 15 feet, etc. then your SAC rate is somewhere between 0.67 and 1.2. That is still very good. Without knowing your average depth it is hard to know what your SAC rate really is.

SUMMARY: based on the numbers you have given, you Surface Air Consumption (SAC) rate is between 0.67 (very good) and 1.2 (not good but okay for a first dive). I'd guess you might have been around 1.0 and that is still okay.

Just as before we got out of the water and got dry right away and actually changed back into regular clothes as that was it for the day. We logged our dives and again discussed what happened. This dive was 22 minutes starting as a "B" and ending as a "K". Because I had troubles at first I actually had drifted a bit lower than my first dive and my computer was showing 34 feet (8 feet deeper than my first, which again is not a good thing). Having had too many problems and using more air to stay buoyant and breathing more to work harder I started with 3200 PSI and dropped to 1600 PSI. I used about 600 PSI more on my second dive and was down for less time too.

First, you state earlier that your second tank was a steel 90. Not familiar with any steel 90 cylinders. Maybe it was a steel 80 (which is really 80 cubic feet). You mentioned 3200 PSI. I am familiar with a steel 95 but it is 2640 PSI max.

More nerdy math stuff, summary at the end...

For a steel 80, 1 PSI is 80 / 3442 or 0.0232 cubic feet. If you breathed 3200 - 1600 or 1600 PSI then you breathed 37 cubic feet of air. Only 6 cubic feet more than dive 1.

Remember also that the deeper you go, the faster you breathe air. If the maximum depth of dive 1 was 26 feet and dive 2 was 34 feet you went from breathing 1.8 times air to 2.0 times air. Breathing 37 cubic feet of air at 34 feet in 22 minutes would give you a SAC rate of 0.84. You used a lot of air filling your BCD, you were not horizontal in the water (this will make you use my energy which means more air), you were kicking all the time to stop from sinking. The numbers you presented are not surprising. A steel tanks is typically 5 to 6 pounds less buoyant than an aluminium tank. If you didn't adjust your weights you were 6 pounds too heavy. Remember in the pool how much difference one clip on weight made. I think for someone with 6 pounds too much lead, you did pretty good.

SUMMARY: you should have removed 6 pounds of lead when switching to the steel tank. Being this overweight you should expect to use a lot more air. If you had adjusted your weight you would have had a really good SAC rate.

 

[XS-NRG]

scubadiver888,

Great info. Thanks for that. Yes, my second dive was a disaster. I didn't remove extra weight and should have. Most of the extra air I used really was spent adding to the BCD and of course more exertion through kicking. I learned this the hard way but still managed. Dives 3 and 4 were way better as you'll soon find out. I had aluminum 80s and only 24 lbs today compared to a steel with 30 extra lbs on dive 2. Dive 2 was 12 lbs overweight.

 

[XS-NRG]

OW Dives 3 & 4

I have come to the end of my course now and these last 2 dives are the final step to becoming Open Water Certified. As before, my day of dives started the previous day going through gear, preparing it and getting everything else ready for an early morning start. As I had troubles with my reg/tank last time I again checked it over to catch any potential problems and was happy to see that nothing was wrong this time. Apart from this I was ready to go.

It was an early morning start and a 1 - 1.5 hour drive again except this day was quite a bit colder and the wind was relentless. Had I not been in this course and someone asked if I wanted to come I would have quickly told them where to go but there was too much excitement about getting the whole thing done. Once on site most of us got our gear all ready to go ahead of time and into the warm kitchen area. The water was only 8 degrees C today and we didn't want to waste any time. Again, before starting out we went through our log books and planned our dives and just as before we were diving at altitude. 5000 feet above sea level with a 2000 foot climb put us at a "D" pressure group and with our hour SIT we were starting as a "B". Today we were going to be going deeper and longer. 40 ft max depths for 30 mins the first time with 1:15 SIT and 40 ft max for the second dive for only 20 minutes. My buddy and I did not have a computer this time so everything was via tables/eRDPml. Most of the information on these dives is identical to to Dives 1 & 2 earlier so I will try not repeat myself.

Dive 3

After donning our gearing and getting into the water my first task was to do a weight check. I had an aluminum 80 on and a 10 lbs weight belt and 2 x 10 lbs integrated weight pockets. I quickly dumped my air from my BCD and held a breath and sure enough I started to sink. TOO MUCH WEIGHT. So the first and easiest thing to get rid of was my weight belt. Now that I was 10 lbs lighter I wanted to try this again and this time I floated at eye level and seemed to be good. The next test was to go out a bit deeper and try to sink down. After a few failed attempts I realized I now didn't have enough weight. Back to the shore to get 2 x 2 lbs weights (1 for each pocket) and finally I was good to go.

Now was time for some skills. We didn't have many skills to have to perform today and the majority of them were done on this first dive of the day. First we did a surface swim to the buoy and used our compass to get there. Our heads were underwater and today was exceptionally colder. I found my face feeling slightly frozen and it was hard to breathe. I caught myself taking quite short and shallow breaths and did my best to elongate them while acclimatizing to the water temperature. It didn't take long before I was feeling fine and before long we were ready to descend.

Being properly weighted I was able to make a very nice slow controlled descent to the bottom of the line and was able to add the right amount of air to my BCD to stay off the bottom completely. There was a bit of time correcting my buoyancy at depth but it didn't take long to get everything sorted out. Our first order of business underwater was to do our CESA (Controlled Emergency Swimming Ascent) from approx 25 ft. In our pool session we were told that this would be much easier to do vertically than horizontally and sure enough that statement was true. So true in fact that I was still exhaling when I hit the surface. Being confident in that it was time to go for a free swim for 10 minutes out and 10 minutes back using natural navigation. The area we were diving in was a bay shaped like a giant bowl. Swimming out had the ledge on the left and returning had the ledge on right. It was estimated that no one would actually hit 40 ft or be out for the entire 30 minutes due to temperatures but my buddy and I were feeling good and in no time were at 40 ft and well ahead of the pack. Now I knew there was a sunken ship (we descend on top of it) and there was also a row boat, but what we found next I was not expecting, a canoe. Somehow at around 35 ft we found this canoe by accident and checked it out but to my disappointment found that my camera had run out of memory and some great footage was lost. Oh well. We weren't able to really check the whole thing out though because it was on a decline and the bottom of it was lower than 40 feet so we didn't bother and simply continued on. Having no computer or dive watch we had no idea how long we had been out so I simply thought it might be a good idea to turn around and ascend to 15-20 feet for our entire return so that we ended up doing our safety stop the entire time we were returning.

Prior to leaving I took a heading on my compass to the ascent line and we decided to try to swim back using the compass. Because some other divers were in the area there was quite a bit of silt kicked up and we were heading straight into a silt cloud and quickly lost our bearings and somehow got turned in the wrong direction. I knew this was the case because the ledge should have been on the right returning but it was actually on the left. This didn't really make much sense and my buddy pointed that we should go a certain direction. So we did. After about a minute of this nothing seemed right at all and the visibility was next to none. In our confusion we managed to slip back down to about 30 feet and had no idea which way to go. My compass heading was going to be no use either as we had turned approx 90 degrees and as we were about to find out, if we followed the heading we would have been in the wrong area.

At this point we had no choice but to surface to gather ourselves so we could figure out which way to go. As we were down to 30 feet we now had to ascend again and make another safety stop. This time we just hovered at 15 feet and hung out while completing our stop and then continued to surface. Once at the surface it quickly became apparent why and how we managed to lose our bearings. Silt aside, we were swimming in a giant circle. In fact, to think about this more clearly we were swimming in a giant bowl following it all the way around. It's no wonder we thought we were returning and yet the ledge was still on the left side. After getting a new bearing set on the compass we went back down and planned to stay at 15-20 feet again and see if we could make it back to the line. Due to the silt and focusing on depth and air pressure more so than the compass we were quickly off track again but this time we're heading in the right direction. Soon enough we were coming to the ledge on the opposite side but at 90 degrees and I knew we'd need to make a left turn to get back on track. Sure enough I could faintly see the ascent line, we swam to it and we made our ascent and got ready to go a few more skills.

We had to first remove our weight belt and then put it back on at the surface. Having already taken this off I put it back on then took it back off again and proceeded with the next task. While staying on the surface our next skill was to remove and replace the entire SCUBA unit. I made sure not to put too much air in the BCD this time and had all the straps loose and ready to go. This was still a complicated procedure but even with our 7mm wetsuits on I managed to do it better than our last pool session. My entry method was to lift it over my head but instead ended up being more of a somersault into it. This seemed to work just fine and it was now time to exit the water quickly and get warmed up.

After drying off in front of the fire we went back to our log books to finish logging the dive and the profile this time was as such: 4 degrees C outside air temp, 8 degrees C underwater, started with 3000 PSI and ended with 800 PSI for a 30 minute dive to 40 feet (rounded to 60ft to consider altitude and cold water). After a 1:15 SIT time (which was more like 1:30) we were ready to go back out.

Dive 4

First things first, weight check. I was still good and ready to go. Having found the canoe we wanted to find the row boat next and were given the appropriate heading of 240 degrees off the port side window of the ship. After a few minutes of exploring the ship we made our way around the boat found the window and then set the compass. This time the visibility was a bit better and the skill for this dive was to use the compass to go out and then set a reciprocal heading to return to the ship. This time around the compass navigation was better as I focused more on it than air supply as we had only just descended with a fresh tank of air. In no time we found the row boat and began to explore it. The stern of the boat was actually right at 40 feet so again we didn't venture further and as discussed on the surface our objective was to find it, return to the ship and then explore the ship and stay around it for the duration of the dive.

I quickly set a reciprocal heading and began swimming back only to land right back where we started. I'd say the skill was a complete success this time (even though I'm still quite interested in taking the underwater navigation course to learn even more). Now that everything was complete we decided to explore the ship as we hadn't really done that yet. Most of the ship is just boards and stringers now so we explored the top of it and found alot of interesting things. Prior to entering the ship I made sure there were no over head shelves and made sure we weren't entering a confined overhead environment. Everything was clear so in we went (which was really just on top of what was left). Having not found any fish over the past 3 dives I was quite thrilled to find dozens of fish this time. In fact, the whole boat seemed to be a giant apartment for the fish and clearly was a hiding spot for them.

The boat in on a diagonal slant and before long we were at 40 feet again and didn't want to go any further so we simply turned around and explored the other side of the ship as we ascended. More fish, more fish and yet more fish. This is really not to be exaggerated, there was probably around 100 and some of them were quite big when comparing to my arm length. Obviously the magnification effect underwater always makes items seem huge but comparing it to something I'd bring above the surface (my arm) it was the entire length of my arm. Impressive. This time we were given a dive computer to use but were only allowed to use it as a underwater watch (as it had another divers profile on it for RNT etc). I knew I wanted to be more conservative on this dive and actually stay down less time than we planned. We had discussed this on the surface prior to going down. With only a few minutes left on the clock we just hovered around the ascent line and I decided to just have some fun and do some aerobatics. Barrel rolls, front flips, back flips, and corkscrews, it was a fun way to end the dive while waiting at our safety stop and the whole time I stayed neutrally buoyant and balanced and didn't touch the bottom once even though I came close. My buoyancy is much better. It really pays to do a weight check on the surface.

Once at the surface we again went to the kitchen area where the fire was going to warm up and get out of our wetsuits and back into regular clothes. Finally we logged our dives and this time the profile was as follows: 4 degrees C outside air temp, 8 degrees C underwater, started with 3000 PSI and ended with 1700 PSI for a 16 minute dive to 40 feet (rounded to 60ft to consider altitude and cold water).

This is it, all the classroom work is done, pool sessions done, and 4 OW dives with all our skills complete. Although the official word on our progress won't be known until next week I'm pretty confident that I have passed and should now be Open Water Certified!!! :cool2:

 

[ScubaBB]

This is the kind of thread I like, very informative.

 

[scubadiver888]

Great thread XS-NRG. Thanks for posting such a detailed and informative thread. It is student like you that make me glad I became a divemaster (and hopefully some day instructor).

 

[XS-NRG]

This is the kind of thread I like, very informative.

Great thread XS-NRG. Thanks for posting such a detailed and informative thread. It is student like you that make me glad I became a divemaster (and hopefully some day instructor).

Thanks guys. Glad you enjoyed it. I'll probably do the same for this for each of the different courses I take. I'm thinking of starting a website actually and putting this all on it including dive logs and pictures :cool2:

 

[rivers]

My only concern is you being allowed to have a camera with you during your open water course...

 

[Hawkwood]

My only concern is you being allowed to have a camera with you during your open water course...

That's one. No timing device for OW3 is another - how did you know how long you were underwater? As well, the way the narration was written it sounds like there was a lot of time spent swimming without supervision of any kind.

Maybe a bit of clarification would stave off any criticism.

 

[XS-NRG]

My only concern is you being allowed to have a camera with you during your open water course...

The camera is a GoPro wearable camera. You turn it on and forget about it. It was strapped to a chest harness and I don't touch it the entire time. I didn't realize I ran out of footage until I got home and tried to check it out.

That's one. No timing device for OW3 is another - how did you know how long you were underwater? As well, the way the narration was written it sounds like there was a lot of time spent swimming without supervision of any kind.

Maybe a bit of clarification would stave off any criticism.

We were in a group of 4 and one person had a timer, but we got separated and lost. That's why I wanted to turn around right away for 2 reasons. 1: we didn't know where we were, 2: I didn't know the amount of time we were down. After surfacing to get our bearings we noticed no one else had surfaced and would still be within our time limits. We swam back right away and once we got to the line everyone else was also surfacing so I know we were within the time limit and verified this with the rest of the guys we got separated from. Our 2 instructors were with us the whole time but after we got lost there was obviously some separation. To be honest there was a brief moment of panic when I realized we had no clue where we were but quickly got rid of that and simply focused on staying right next to my buddy and thinking logically about what to do (hence the decision to surface).

Hopefully that clarifies things.