Air share

[Blackcrusader]

That's right that in some occasions, I have followed a DM and I was not happy. In this particular case, I still had air but I breached my own personal rules. I think that I need to learn to say no immediately and not wait for the last minute.

You need to inform others of your personal rules if you want them to know why you want to call a dive. So explain to your guide that you expect to be at the safety stop level before you get to 50 bar and that you will surface if you get to 50 bar. Of course if you are 50m away from the dive boat it might have been better to have stayed underwater to get to the boat ladder. Sometimes it's a bit easier to swim than being on the surface and be on the boat with 45 bar.

You will get the experience from the dives you are doing. Often you write your wife is your dive buddy so you as a pair can certainly plan to exit the water when the first of you gets to 50 bar. That's easy as you can manage your depth so that when you get to 60 bar you start to make sure you are at less than 10m depth, then get to 5m complete your safety stop and exit the water.

On my recreational diving most of the time I am finishing with way more than 50 bar so that limit has never been a fixed personal rule for me. Some shops ask that you do 55 - 60 minute dives and exit the water or exit with 40 bar. Some places say you can dive and exit with 40 bar and no time limit. Some are 75 minutes max time for a dive. Probably the favourite of my last 250 dives was when I asked the dive center owner if myself and my guide could just dive with no time limit and end the dive with 50 bar. He knew I wanted an unfettered dive where dive time was not limited. It was also my guides birthday so it was just the two of us. Both experienced and we discussed our dive plan and basically it was let's do the wreck dive to 34m on air, come up a sloping shelf to the reef and not go into deco. His DC was limited more on NDL to mine so we had to pay attention to our own DC's.

So we did the dive and got back on the boat with 50 bar. We stuck to the dive plan. 93 minute dive time max depth 34m. ( I would have liked to have stayed to 100 minutes as still had plenty of air ) Stayed a couple of minutes to NDL till we got to shallower water where NDL time didn't need to be monitored so much. Either of us could have called the dive if low on air or cold or lost interest. For both of us it was one of the best dives we had done together. One of my favourite dives in the last decade for me. I remember the dive as I got some photos of rarely seen sea horses.

I try to remember the good dives that give me happy memories. A few difficult dives I still remember though. You are learning from doing more dives.

 

[Edward3c]

All this talk of surfacing with 50/whatever bar. I’ll often end a dive wit 140bar or more, then do a second dive on the same cylinder. I did that last Saturday’ dive 1, 37m for 47 min; dive 2, 18m for 30 min.

 

[Dody]

@Dody some comments:
1) it isn't a smart approach to end ALL the dive at 50bar. It can be not enough at 40m with strong currents, and way too much at 10m. You should discuss the gas planning at any dive.

It is just a safety margin. I once did a shore dive and when we surfaced the weather was so bad that we had to wait for an hour before climbing the rocks and getting onshore. Almost the whole time, we had our regulators on because we were beaten by the waves. If I surface with 20 bars, I only have about 10 to 20 minutes to get out.

 

[ginti]

It is just a safety margin.

No, it is not. A safety margin is:
- estimation of how much gas you need to surface in stressful condition
- double this amount of gas
- considering the equipment used to monitor the gas (some become less efficient below a certain pressure)
- add a safety coefficient depending on the condition
The calculation of a safety margin requires different calculations at each dive. It isn't rocket science, it's easy maths (multiplications and additions, nothing more), so you really can do it every dive, even without pen and paper.

I once did a shore dive and when we surfaced the weather was so bad that we had to wait for an hour before climbing the rocks and getting onshore. Almost the whole time, we had our regulators on because we were beaten by the waves. If I surface with 20 bars, I only have about 10 to 20 minutes to get out.

I have never heard of any situation like this, and I met people who do exploration dives in the middle of the ocean, literally (scooter dependent, 150m deep). So this is what I believe: if you wanted to keep the regulator in your mouth for comfort, that's understandable, but if you really needed to survive - most likely your BCD was not full enough.

Anyway, I hope it was an unpredictable change of weather; in the future, check the weather in advance, it is part of the game. With such bad weather conditions, you shouldn't be diving

 

[Dody]

No, it is not. A safety margin is:
- estimation of how much gas you need to surface in stressful condition
- double this amount of gas
- considering the equipment used to monitor the gas (some become less efficient below a certain pressure)
- add a safety coefficient depending on the condition
The calculation of a safety margin requires different calculations at each dive. It isn't rocket science, it's easy maths (multiplications and additions, nothing more), so you really can do it every dive, even without pen and paper.



I have never heard of any situation like this, and I met people who do exploration dives in the middle of the ocean, literally (scooter dependent, 150m deep). So this is what I believe: if you wanted to keep the regulator in your mouth for comfort, that's understandable, but if you really needed to survive - most likely your BCD was not full enough.

Anyway, I hope it was an unpredictable change of weather; in the future, check the weather in advance, it is part of the game. With such bad weather conditions, you shouldn't be diving

It was completely unpredictable but we know that this is a possibility. It happened to me several times in Cape Verde. The weather is perfectly fine when you jump and rough when you surface. And it has nothing to do with the tides or the sky which is always cloudless. It happens only in the last 50 meters close to the rocky shore. You can take your chance and try to climb. I did it once and my knees have not forgotten. So, in my view, having one hour of breathing air in my tank at surface is a safety margin.
We call a lot of dives here because of that. In fact, I had a plan to reach 100 dives in 9 months. I will be 10 dives short because of called dives. The entry can be managed but the exit can be very risky. If you have ever been slammed and submerged by a huge wave on sharp rocks, you know what I mean. Of course, you always have the option of backing up a few hundreds meters where there is no wave and wait but as I experienced it, it can take an hour... or more.

 

[Dody]

It was completely unpredictable but we know that this is a possibility. It happened to me several times in Cape Verde. The weather is perfectly fine when you jump and rough when you surface. And it has nothing to do with the tides or the sky which is always cloudless. It happens only in the last 50 meters close to the rocky shore. You can take your chance and try to climb. I did it once and my knees have not forgotten. So, in my view, having one hour of breathing air in my tank at surface is a safety margin.
We call a lot of dives here because of that. In fact, I had a plan to reach 100 dives in 9 months. I will be 10 dives short because of called dives. The entry can be managed but the exit can be very risky. If you have ever been slammed and submerged by a huge wave on sharp rocks, you know what I mean. Of course, you always have the option of backing up a few hundreds meters where there is no wave and wait but as I experienced it, it can take an hour... or more.

Just to explain a little bit more. We usually have one or two people staying on land, the spotters. The divers stay in the rough zone but not so close to the rocks. The spotters monitor the sea and tell us when to fast swim to the shore to get out. More than often, before we can even climb, they tell us to back down because a huge wave is coming. After a while, it is fun.

 

[ginti]

It was completely unpredictable but we know that this is a possibility. It happened to me several times in Cape Verde. The weather is perfectly fine when you jump and rough when you surface. And it has nothing to do with the tides or the sky which is always cloudless. It happens only in the last 50 meters close to the rocky shore. You can take your chance and try to climb. I did it once and my knees have not forgotten. So, in my view, having one hour of breathing air in my tank at surface is a safety margin.
We call a lot of dives here because of that. In fact, I had a plan to reach 100 dives in 9 months. I will be 10 dives short because of called dives. The entry can be managed but the exit can be very risky. If you have ever been slammed and submerged by a huge wave on sharp rocks, you know what I mean. Of course, you always have the option of backing up a few hundreds meters where there is no wave and wait but as I experienced it, it can take an hour... or more.

So, two quick thoughts here:
1 - if it is only in the 50m closest to the shore, and there is so much variability, better stay 60m (or more) far, wait for the waves to reduce, and then exit.
2 - if you want, you can add a bit of gas to your "minimum gas" (gas at which you call the dive) because this is actually an environmental factor, even if I disagree - in the end, it is personal. But you still need to do the calculation. How much gas do you want at the surface? 20bar? Then calculate the minimum gas for the dive as if conditions were perfect and then add 20bar. Calling always a dive at 50bar just does not make sense (to ascent from 40m requires more gas than from 10m!)

 

[Dody]

So, two quick thoughts here:
1 - if it is only in the 50m closest to the shore, and there is so much variability, better stay 60m (or more) far, wait for the waves to reduce, and then exit.
2 - if you want, you can add a bit of gas to your "minimum gas" (gas at which you call the dive) because this is actually an environmental factor, even if I disagree - in the end, it is personal. But you still need to do the calculation. How much gas do you want at the surface? 20bar? Then calculate the minimum gas for the dive as if conditions were perfect and then add 20bar. Calling always a dive at 50bar just does not make sense (to ascent from 40m requires more gas than from 10m!)

I agree with 2). In fact, I might have poorly explained myself. I always want to surface with 50 bars. Peace of mind, no matter what. I don't need to calculate that. I just calculate how to get at safety stop with at least 60 bars. This is what I do when I dive with my buddy. When I dived with a DM in the past, I made the mistake of not communicating this rule expecting them that we need to plan the safety stop when I tell them that I have 70 or 80 bars (at the end of the dive, we are always shallow. I am never below 20m when I am below 70 bars). This mistake won't happen again.

 

[ginti]

I agree with 2). In fact, I might have poorly explained myself. I always want to surface with 50 bars. Peace of mind, no matter what. I don't need to calculate that. I just calculate how to get at safety stop with at least 60 bars. This is what I do when I dive with my buddy. When I dived with a DM in the past, I made the mistake of not communicating this rule expecting them that we need to plan the safety stop when I tell them that I have 70 or 80 bars (at the end of the dive, we are always shallow. I am never below 20m when I am below 70 bars). This mistake won't happen again.

Ok, I get your reasoning; the way I imagine it, I do not agree (I wouldn't dive if I couldn't breathe with my mouth at the surface), but it is also true that my imagination is probably far from reality.

However, keep in mind that this approach is good only for the dives you described. For dives without waves at the surface, it simply does not make any sense. [EDIT: I mean, it does not make sense to have 50bar more at the surface... ]

 

[ginti]

Another critical point; if the DM didn't know that you wanted to have 50bar at the surface, what the DM did here:

Never been OOA or had to share air. But in two occasions when I was diving with DMs that I did not know in new locations, I signaled LOA (50 bars). They signaled back Ok and continued the dive, still stopping to see critters or whatever. In both cases, I ended the dive with between 20 and 40 bars and I was pretty much pissed off.

is perfectly fine, assuming that you were not deep. You really must be sure that this:

I don't care if we are shallow and close to the exit point. At 50 bars, we end the dive. Period. I am so into this rule that unless the surface conditions are really bad, I would deploy my DSMB, surface and swim to wherever I need to exit.

Is fine for everyone BEFORE the dive; if it is not, then it is absolutely normal to continue the dive (again, shallow and with a good safety margin, so to ensure that no one will run out of gas).

Also, consider that a DM may read your SP when you signal LOA. They often read the SPG of their clients, just to be sure that everything is fine (at least, where I dive). Now, if you didn't say previously that you wanted to surface with 50bar, and you signal LOA with, say, 80 bar in a 15l tank at 20m, they may just think that you are not even able to properly interpret your SPG. Not only they will not end the dive (pissing you off), they will also think that you are not a competent diver, unable to manage your gas - in other words, only easy boring dives for the future with these operators.

If they knew and agreed that you wanted to surface with 50bar, well this is another story.