Thank you for the video. My son (11 years old) just got certified but was asking ME (not yet certified) to help him with dive tables. If you have a pre-adolescent, then you know that they aren't the best at organization or "the details". With him not having a computer, these DETAILS are quite important... Thanks again.
I was NAUI certified in 1972. My last dive was 1975. I started diving again in September 2021 when I went to Beaches at Turks and Caicos. I had an advanced diving class after I was certified but when I got a replacement cert card it had no record of my advanced class. Beaches offers PADI classes and in September they asked if I wanted to take their advanced class. At that time I just wanted to make some 30 dives. I did have to take their refresher class since I had not dove for a long time. Part of the class was the dive tables. I had such a good time that I went back the following May in 2022 and took my daughter. I was going to take the NAUI advanced class in San Diego but I got to thinking, Pacific Ocean water temps and visibility is not that great. So when I went back in May I took their advanced class which consisted of 5 dives and 80 degree water with 200 foot visibility. I went to my local dive shop recently and while I was there I bought a NAUI dive table card. I got home and worked through it and I think it is much easier to use. It is a bit different and I guess it is more conservative. I think it is worth a look if you want to use the tables in addition to your dive computer
Thank you so much for making this easy to understand. I kept having everyone go through it so fast because it so simple to them and it was a blur for me.
This explanation is very helpful. You made it simple and clear for me to understand. I'll pin this video because I need a little more time on the diving tables.
I am also a PADI DM and have been certified since 1981 ( no old fart jokes, please) and I agree with Mr. Corke. The best explanation of the tables and the actual relationship to the body I have witnessed in all my years as an active diver.
Thanks for the review. I dive with a computer but every year or two have to reteach myself how to use the tables. Nice simple method for remembering which table does what and why. Thanks I'll keep this video in my back pocket for review later
Excellent video, now, I am new to diving, so here's my question, all this is based off no decom, time, so, lets say I want to decompress, how do I factor in the nitrogen into the time for decompression and how to subtract that from my dive time, Etc. I hope I asked that correctly....LOL, That's why I didn't ask.
Hello Jack Grant,great question. Most dive tables are specifically designed for no decompression diving. Several will have special rules to follow in the event a diver mistakenly goes into decompression. And it should be stated that, unless you are properly trained for decompression diving, you should refrain from doing so. In today's diving, dive computers are the standard, and should always be used. It takes the confusion out of the planning and diving process, and most dive computers will walk you out of decompression mode as well.
Hello Ed, the Navy tables in comparison to others is very liberal. One of the first videos we produced here on our channel, was a comparison video of several different tables, and the US Navy Tables were the least conservative. Here is the link to that video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-V_sQCY8R2Kg.html
should the room storing LN2 have ceiling exhaust or low level exhaust one says ceiling exhaust as nitrogen is lighter than oxygen to so extract effectively at high level; another says the when accidentally pouring some LN2 on the floor, low level exhaust can exhaust out nitrogen which is just been vapourized, not letting them even have chance to reach mid/high level of the room
Let say I gonna do a first dive at 80 ft and seconds dive at 100 ft, and I have 32% and 34% enriched air. Which mix should I go with so that I can maximize my no-deco time and minimize the residual nitrogen (+adjusted no-deco)? Hope you understand!
Hello Zen, great question. So by running the dives real quick, using the SSI Air and Enriched Air Tables (disclaimer: all profiles were calculated using the Equivalent Air Depth) and using the two dives and mixes you specifically asked about, I would do 80 feet for 50 minutes using Nitrox 34 and then the second dive to 100 feet for 22 minutes using Nitrox 32. Understanding this is a reverse profile your minimum surface interval would be 8 hours in between dives, but your total bottom time would be 72 minutes. If you reversed the mixtures and did the 80 feet dive for 40 minutes using Nitrox 32, and then did a 100 feet dive for 26 minutes using Nitrox 34, your minimum surface interval would still be 8 hours in between dives, and your total bottom time would be 66 minutes. This question has gave me a great idea for a video. Stay tuned as this question will be featured in an up coming video, explaining reverse profiles and Nitrox.
Hello sukhvir singh ambawata, can you revise your question. Are you asking for the specific Atmospheric Pressure at 4000 meters, or are you asking what the Nitrogen Saturation would be at that depth.
Hi there! I get how you calculate the RNT+ABT = ESDT. But I don't know how to calculate it if you use another blend in the second dive?? For example: 1st Dive: 36%EANx, 22m for 45 min. 2nd Dive: 30%EANx, 16m what will de no Decompression Limit and RNT be?? Thanks in advance!!
Hello Gina Stussi, great question, however, as we will discuss, is an incomplete question. In a situation where we are using blends that are not shown on the SSI Combine Air/EANx Dive Tables, anything other than 21%, 32%, or 36%, we would simply use the Equivalent Air Depth formula {(FN2 / .79)(D in meters +10) -10} to convert everything back into 21%. This makes the calculations a lot easier. So in the case of this question, it would go as follows. Dive 1 would be 22m for 45 minutes using 36% changed to 15m for 45 minutes. Dive 2 would be 16m using 30% for (time to be determined by table 3) changed to 12m for (not yet determined). Now a quick note, you would not need to do the EAD formula for the 36% blend as its on the Dive tables, however, its good practice, so we will leave it in there. Now its a matter of just doing the profile. We will also need to calculate the minimal surface interval since you did not state how long we would be out of the water. So here goes. Dive 1 = 15m for 45 minutes yields a pressure group of G. Moving over to table 3, Dive 2 = we can calculate a 12m dive with (Spoiler Alert----there is not enough information in your question to continue), however, we will push on and max out the most time available (based off a generic chartered dive). Continuing on 12m for 45 minutes ( as most charter dives are going to be around the same time frame). The beginning pressure group after (a soon to be determined pressure group) would be G. Thus according to table 2, the minimal surface interval would be 10 minutes. And to finalize the answer, we can go back to table 3 and see that the new Adjusted No Decompression Limit and Residual Nitrogen Time (based off the assumption of bottom time for dive number 2) would be (ANDL 57 minutes) and (RNT 73 minutes). This is a very thought provoking question, but one as stated earlier, needs more information. Your overall bottom time will change for dive two based off how long you perform a surface interval. Also, if the question was completed with the wanted (planned) bottom time for dive two, then you could very easily calculate the minimal surface interval as we did above. By using the hypothetical manner of saying most charter dives are between 45 minutes to 60 minutes (45 minutes in this case), we can then simply use table 3 to derive the answers for the ANDL and RNT. Hope this helps. A quick side note: We have an entire video series on using the Equivalent Air Depth that you may find interesting. EAD ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-yL0adMvWlaY.html Nitrox and Reverse Profile ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-CO9qYh6_obM.html
Hello Anthony, unless you are using the Multi Level Electronic Recreational Dive Planner or the Standard Recreational Dive Planner (both PADI products), or you use the older PADI Wheel, there is not a way to calculate off gassing during the ascent phase of the dive. However, a computer does this with ease.
Just started classroom instruction for diving. The RAT system you explained is confusing me. You say that in reality, you are only under the water for 33 mins. But you complete the math by adding and coming up with 50 and then using the 50 to get your new group. I assume you are using the 50 to be be cautious and err on the side of caution?
Hello @172sbct. RAT stands for Residual, Actual, and Total. The residual time is how much nitrogen is still in your tissues after a surface interval. The actual is the amount of time you physical plan to stay under. The Total is both the actual time and the residual time added together for a more liberal calculation of how much nitrogen your body will have absorbed after the second dive. Hope this clears things up for you.
Hello paniolo prep, when using tables (regardless of which set of tables you use), table 3 will give you your residual nitrogen time, and the new adjusted no decompression limit for a given depth.
Hello JorgeandHisVideos, I can't really speak for what Seals train for, but I would feel very confident in saying that all divers learn about Nitrogen Storage on some level.
Im not understanding. if your adjusted NDL is 33 min at your planed depth of 60 feet why do you have to do the math as if you were at depth for 50 minutes?
Hello Kyle B, You still have to calculate the residual nitrogen that is still in your system. This residual nitrogen is accumulative until it has been off gassed.
@@LakeHickoryScuba not really, I've been driving for over 30 yrs, but I was watching your video and thinking as if I was a new diver, it seemed like you were ruching it just a little thats all. I actually thought you were thorough in your teaching. I appreciate you responding to my message, and as usual, Dive safe and keep up the good work. Thanks for sharing your videos with the world.
