OP
I drank the koolaid!
- Thread starter Leejnd
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ScubaFeenD
Contributor
Mathematics is your friend
. Anyway, as much as it is a pain in the tookas, the more you do these problems the quicker you can work out gas management on the fly, while at depth (to calculate how much air you should have left based on BT), and it makes working out a dive plan when circumstances change on a boat really easy too. I cannot tell you how valuable practice with these problems is.
The first is a 40 minute dive, and the second is 50; do note the use of the words "must" and "prefers", because they change the gas planning. And also note that returning to the upline isn't the end of the dive . . .
Blackwood
Contributor
As Lynne mentioned, the use of the words 'must' and 'prefers' are not arbitrary.
In one case, you have to return to the upline (or else insert assumed dire consequences), so you must turn with enough in reserve to get back there even if your buddy has a gas failure. In the other, it's nice to get back upline but not strictly necessary, so you can turn with enough in reserve assuming no failures (in which case you'd go up rather than back and up).
Think about what turn rules you've learned (likely "all usable" "halves" and "thirds"), and which one is applicable to each of those scenarios.
The SAC rate and the average depth and the 20 minutes out are a starting point. Do the math to figure out how much gas you'll use on the outbound leg. I'll call it X.
If it takes me X out and I'm diving thirds, I'm planning to turn with at least 2X plus rock bottom remaining. If I'm diving halves, I'm planning to turn with at least X plus rock bottom remaining. And if I'm diving all usable, I'm planning to simply ascend at rock bottom.
So once you've figured out how much the out leg will use, and once you've figured out which gas rule you're using, you can figure out how much gas you'll need for the bottom portion of each dive. Then add whatever you need to ascend (i.e. rock bottom). All of these can be done in volume and you can convert to pressure at the end, OR you can convert to the SAC rate to pressure at the beginning and work the numbers based on that. Your choice.
Without actually doing them, I hope that helps you figure out how to address these problems.
In one case, you have to return to the upline (or else insert assumed dire consequences), so you must turn with enough in reserve to get back there even if your buddy has a gas failure. In the other, it's nice to get back upline but not strictly necessary, so you can turn with enough in reserve assuming no failures (in which case you'd go up rather than back and up).
Think about what turn rules you've learned (likely "all usable" "halves" and "thirds"), and which one is applicable to each of those scenarios.
The SAC rate and the average depth and the 20 minutes out are a starting point. Do the math to figure out how much gas you'll use on the outbound leg. I'll call it X.
If it takes me X out and I'm diving thirds, I'm planning to turn with at least 2X plus rock bottom remaining. If I'm diving halves, I'm planning to turn with at least X plus rock bottom remaining. And if I'm diving all usable, I'm planning to simply ascend at rock bottom.
So once you've figured out how much the out leg will use, and once you've figured out which gas rule you're using, you can figure out how much gas you'll need for the bottom portion of each dive. Then add whatever you need to ascend (i.e. rock bottom). All of these can be done in volume and you can convert to pressure at the end, OR you can convert to the SAC rate to pressure at the beginning and work the numbers based on that. Your choice.
Without actually doing them, I hope that helps you figure out how to address these problems.
OP
Leejnd
Contributor
YES! 
I figured out the exercises! I've completed all the worksheets and all but two of the online quizzes, including the one that I found most complicated - gas management with dissimilar tanks. I only got one question wrong, which was a silly mistake on the SCR quiz. :doh:
Anyway, my faith in my basic intelligence is restored. I have much still to learn, achieve, and practice...but my biggest fear in this class, which was the math, has been overcome. So...yay!
Thanks to all of you for your help. Definitely, reading through your tips and explanations helped things to click.
I figured out the exercises! I've completed all the worksheets and all but two of the online quizzes, including the one that I found most complicated - gas management with dissimilar tanks. I only got one question wrong, which was a silly mistake on the SCR quiz. :doh:
Anyway, my faith in my basic intelligence is restored. I have much still to learn, achieve, and practice...but my biggest fear in this class, which was the math, has been overcome. So...yay!
Thanks to all of you for your help. Definitely, reading through your tips and explanations helped things to click.
OP
Leejnd
Contributor
2nd day of class. First half in pool, learning propulsion and drills, and being videotaped. 2nd half watching videos and reviewing more course material, absorbing 10,264 UCIs (units of complex info), far exceeding my usual average daily rate of 37 UCIs.
After cringing through those videos, I have only two words: I SUCK.
Must go to bed now. Must be up at 4am to catch the ferry to Catalina.
Man, I must want this bad.
(I will toot my own horn just a tiny bit for completing the swim test in 9:15, surprising the hell out of myself.)
After cringing through those videos, I have only two words: I SUCK.
Must go to bed now. Must be up at 4am to catch the ferry to Catalina.
Man, I must want this bad.
(I will toot my own horn just a tiny bit for completing the swim test in 9:15, surprising the hell out of myself.)
Ramsy
Contributor
Leeann,
The reason all the post-Fundies class reports seem to revolve around this theme of utter exhilaration for finishing the class is because we all have been where you are right now. You are learning new skills in a very task loaded environment, something you are undoubtedly not used to when diving. By going from the "I suck" stage to finishing Fundies, I guarantee that you will have the same appreciation for the class as expressed by other Fundies graduates on this board. Everyone that goes through Fundies undoubtedly felt the same way as you do now at the same stage of the process. Hell, when I went through Fundies, I recall my instructor asking me to demo my back kick. I remember, kicking and kicking and kicking and going nowhere and feeling utterly frustrated. However, by sticking with it and working on it, I was able to get it. And once you get it, you will always have these skills - kind of like riding a bike. So, stick with it. It will all come together. And when it does, I guarantee that you will look back at this whole process with admiration.
You beat me by a minute and 15 seconds . . . Good for you!
We all suck in Fundies. One of the biggest utilities of the class is the paradigm change, from "what I'm doing is fine" to "I could be doing so much better". You make that mental leap, and if you keep it, you will continue to become a better diver with every single trip underwater, for the rest of your diving career.
We all suck in Fundies. One of the biggest utilities of the class is the paradigm change, from "what I'm doing is fine" to "I could be doing so much better". You make that mental leap, and if you keep it, you will continue to become a better diver with every single trip underwater, for the rest of your diving career.
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