i tried to fly out today and i ended up being bent

[Blastman4444]

I have never said I only would change the time to 48 hours until I fly not sure where that came from. I plan to dive more conservative then the normal there could be other factors involved and even if it is not any value to wait more then 18 hours I don't care.

 

[Blue Sparkle]

I have never said I only would change the time to 48 hours until I fly not sure where that came from.

I got that idea from this post:

The purpose of this thread is to warn other divers that to watch out when flying if you at all cost give your self at least 48 hours after deep diving everyone will say,"I knew that why didn't you". There will be a few who will end up like me who only dives 1 time a year and wants to get in a dive the last day before they go back home.

But then maybe what you are articulating in your current post is that you wouldn't wait 48 hours to dive after a shallower dive but only a "deep" dive? It's a little tricky sometimes with the punctuation and that may be where some confusion is occurring.

... even if it is not any value to wait more then 18 hours I don't care.

And that's completely fair; you should do what you feel comfortable with, and that is informed by your individual experience. Where I felt you might have been a bit "over prescriptive" was where you were advising the mass of recreational divers to wait 48 hours "at all cost" after (recreational) deep dives, and that "everyone knew" that was the right thing to do. You stated it was the purpose of the thread.

That bothered me enough to bring it up in the thread because I felt that diving more conservatively/planning/etc. would probably be more effective for most divers (at least according to what I understand).

 

[Golfer38]

.....

 

[Golfer38]

Hello everyone,, New Diver here.. My son (12) and I justgot OW cert'd in Oct as we were going to the Caymans in Nov (we just got backfrom 8 days). Being cert'd in a quarry made us a bit skeptical as to where ourdiving would start and/or end. Due to the the typical dive shops weights,equipment, etc it took us almost an hour to get ready for diving. The watertemp was fine as the suits protected us but it was just not fun.

Well, we went to the Caymans and had about 12 great dives.. Which leads me tothis forum... I found this forum and after the intial greetings"hello" I jumped right into this area of the forum so I can read upon accidents/mishaps and how better to prevent them. The other areas can wait.So we go from scepticism to enjoyment in one trip. Being a newbie and readingthis thread, I have a few questions... As well as some concerns of my own aswhile diving in the Caymans, we went down to 100+' a few times (Never more than105'). And I dont want to become over-confident while only having 15-20dives...

In regards to this thread, I have a couple questions...

1) The OP states that his first dive was at 93' for 24 minutes. So in mytraining, we have to go to the next depth, which is 100'. That immediatelyshows, per the calculator, that it is beyond the limit. It only goes to 20minutes at 100'. If we use 90', the 24 minutes would give us a "P"PG.

with a SI of 49 minutes, we get a PG of "G"

Now going down to 101' (110' for calculations) the diver could only go down for5 minutes. If we use 100', it would be 8 minutes.... Am I correct?

I ask this as while diving in the Cayman, we dove on our first dives, to atleast 80' each time. The the 2nd was at (about) 65'. Its easy to get tocomfortable and become a casualty, which nobody wants. BTW, I dove at theKittyhawk about 1pm the day the pulled a man out (3pm) at the same spot. Helater died...There is another thread on that in this forum.

There was also some discussions on computers. I think that if my son and I aregoing to stay with diving (and we are) we need to start buying our own gear. Isthere a computer that shows bottom time as well total dive time. It would alsobe convenient to have the ability to dl to a computer.

Thanks in advance, Jim (Maryland)

 

[daniel1948]

Golfer: When you dive tables you have to use the next deepest level, as you are aware from your comments in your post, because interpolation is not reliable. Computers are able to use the actual depth and time, as well as doing multi-level calculations, so that in anything but a square profile to a depth represented by an exact level on the table, a computer gives you more dive time than the tables. It's still a good idea to be conservative and stay well away from NDL limits. I.e., ascend well before the computer says you are out of NDL time.

I'll leave it to others to recommend computer brands. I think most can download to a computer. Some folks will disagree with me, but I'd think that any current model of dive computer would be fine. It's more a question of what features you want: Air-integrated with or without hose, wrist mounted or console, computer without air integration, mixed gas, nitrox, air only, two-gas, etc., etc., etc. This is probably not the thread to ask for computer advice. I'd suggest the new diver or equipment forums for that.

BTW, I think maybe you dived on the Kittiwake, not the Kittyhawk. The Kittiwake was sunk intentionally in about 60 feet of water at Grand Cayman. The uppermost deck is at about 15 feet, making it easy to freedive on, as well as scuba.

Have fun diving, and dive safe.

 

[Blue Sparkle]

In regards to this thread, I have a couple questions...

1) The OP states that his first dive was at 93' for 24 minutes. So in mytraining, we have to go to the next depth, which is 100'. That immediatelyshows, per the calculator, that it is beyond the limit. It only goes to 20minutes at 100'. If we use 90', the 24 minutes would give us a "P"PG.

One thing to note is that there is some confusing information in the thread. For example, although the OP said that his first dive was 24 minutes "bottom time," it was later determined that his computer actually measures "dive time" which includes the entire ascent. I *think* he said he ascended around 60fpm and made a 3 minute safety stop (although I was never sure). That would take around 6 minutes off the bottom time, for around 18 minutes, or a group M on the table, as I read it.

Like you, I was trying to use this thread to compare to some of my own similar-depth dives, so I see where you are coming from.

Welcome to SB and diving

Blue Sparkle

 

[Golfer38]

Daniel, Thanks for the reply.. and yes, its the Kittywake.. I am thinking of aviation (as I am a pilot) and Kittyhawk is the Wright Bro's first flight airport. I was calling Kittywake, Kittyhawk all week while I was in the Caymans. They also corrected me..

 

[Golfer38]

Blue Sparkle, I read that is true when using a computer but I was taught (I think) that the total time (surface to surface) was to be used for calculations. While I was diving this past week, I was wondering the same thing as my DM was giving me figures (TBT (1st dive) - SI - TBT (2nd dive)) that just didnt add up. Maybe with the computer you get a little more time. Which is good, I guess..

Jim

 

[Blue Sparkle]

Blue Sparkle, I read that is true when using a computer but I was taught (I think) that the total time (surface to surface) was to be used for calculations.

....Maybe with the computer you get a little more time. Which is good, I guess..

Jim

The way I understand it is this:

A) On dive tables (at least the PADI ones that I know), the figures given are for Bottom Time. This is all the time from when you first start descending until you begin your ascent.

B) On (many? all?) computers, Dive Time is measured, which is all the time from when you first start descending until you surface again.

So to take the OP's computer time for his fateful dives (which apparently it calls BT but which actually measures Dive Time), and compare it directly to the tables doesn't work, because the tables count bottom time. That made a difference of about 6 minutes on his first dive. It would be an even larger difference on my similar dives because I ascended slower, did a deep stop, and then made a longer safety stop.

The computer does give you "more time" in a way, because it is measuring what you are actually doing. Say you go down to 100', then after a few minutes come up to 60' and toodle around for a while, and then to 30' and toodle around, and then ascend.... well using tables that diving time before your last ascent would all be "100' bottom time," so it would count for "more." That's because the tables don't know your profile.

But I think it's slightly two different things.

1) Simply how you notate the time (Bottom time vs. Total Dive time).

2) The ability of the computer to know that you are making a multi-level dive, and thus to not have to choose "max depth" to use as the guiding factor.

(Maybe the PADI RDP addresses that - I don't know as I have only ever used "regular" tables or a computer.) (I think many dives that would be fine on the computer would put you into NDL on the tables, because of the tables assumption that you are doing a "square" dive.)

 

[kimbalabala]

There was also some discussions on computers. I think that if my son and I aregoing to stay with diving (and we are) we need to start buying our own gear. Isthere a computer that shows bottom time as well total dive time. It would alsobe convenient to have the ability to dl to a computer.

We got "heads up display" masks - the computer is in your mask and the readings are right in front of your right eye - and I love mine. We have the Oceanic version but I don't know if there's a big difference in brands. I like not having to turn my head to look down or to the left at my computer while also trying to continue in a forward motion (or turn or whatever). The other advantage is that when alarms go off I can actually hear them because the computer is attached to my head. I use a Gekko as a backup and have also used a Cobra and I rarely heard alarms - or if I did I was actually hearing my husband's alarms. And you can upload the info onto the computer. Two drawbacks that I know of - sometimes (rarely) a strobe from a camera will cause you to lose signal on the computer so you get a couple of seconds of no feedback - the other is that the only way to find your beginning psi is to either write it down before you hit the water or get it when you download to the computer (unless we just haven't figured it out yet).