How Deep do you Dive?

[Solomon]

I agree with you that 100, 120 feet is not deep. Others were saying this and that was part of my point. The 100 "depth barrier" is artificial and while maybe not arbitrary certainly does not deserve the importance that many place on it. Now 150 feet and greater is deep IMO.

 

[Uncle Pug]

Solomon you were all over the place with depths in your first post... mixing and matching from 40 to 130...

Your lead off statement was: "I don't personally see what all the fuss is about when talking about 100-130 foot dives"

How much difference is there between the 150 foot dive that you call deep in your last post and the 130 foot dive of your first post in terms of NDL and gas supply?

I guarantee that if you don't learn what the fuss is about in the 100-130 foot range it won't be long before you are in the 150 foot range on a single tank of air saying the same thing.

Not meaning to insult you here... but I've been where you are and went where you're headed.

Be wise Solomon... be wise.

 

[Solomon]

well I am mainly differentiating between 130 and 150 on the basis that 130 can be done without it being a decompression dive whereas 150 you would incure some decompression obligation. Also, from what I have gathered effects of narcosis are much more likely at 150. The main point I was making was that 100 feet is not some magic depth. I have seen people post before that they have only been to such and such depth but are hoping to go to 100 on their next trip like it is some sort of milestone. It is not. If you get narced at 90 feet then a person's dives should be done in the context of that factor (as one of many factors that should influence every dive a person makes. Also these factors are dynamic and change every dive). My contention is that some training agencies or instructors have created this mythical 100 milestone. I believe this is dangerous because, while a proper respect for the enviroment we place ourselves in while diving is paramount, creating this barrier can make some people fearful which easily leads to panic should a person find themselves at this depth. Or alternatively, it becomes something to shoot for which can also lead to bad situations. For example, if you tell people you should not or can not dive 100 feet on air it will make some people want to do it (like telling a child not to do something that is the first thing they do). Once they do it and see that it is no big deal then they may also think it is no big deal to go to 150 feet. Now that is a big deal because of the increased odds of narcosis and now we are talking about decompression dive as well. To sum it up, teach people nodecompression diving (which can be done to 130 feet) while explaining the effects of nitrogen narcosis and the increased odds of these effects the deeper you go. With that teaching people to dive within the parameters of their skill and comfort levels and the problem is solved. Personally, I was not taught that 100 feet was some magic depth and never thought it was an issue until seeing people talk about it on message boards. Hell, I went to 117 feet out in the open Gulf of Mexico on an oil rig dive the third dive after certification. Didn't think anything about it. When you give people info that is at best a distortion of the truth and they figure it out on their own then they give little credence to whatever else you told them. That is why I think it is bad for instructors to place to much importance on the 100 foot depth. The emphasis should be on teaching people to dive within their skill and comfort level and it does not take any special skill to go to 100 feet. Does that make any sense?

 

[Uncle Pug]

Originally posted by Solomon
Does that make any sense?

Well it makes sense in that I can understand what you are communicating but I don't agree with you on several points a few of which I will attempt to adress:

1. Narcosis does not hit at a certain depth above which you are uneffected. The effects of narcosis are progressive as you go deeper.

2. As depth increases so does the skill level needed to safely dive that depth. While 100 feet is not a magical number it is easy to remember and forms a benchmark for advancement

3. Every dive is a decompression dive and a dive in the 100-130 range is more so than most realize. The NDL time limits are not magic numbers either and you begin to incur a nitrogen load as soon as you go below the surface... and the deeper you go the faster you take on gas. A problem that develops 130 feet down and 10 minutes into the dive is a serious problem.

However I will add that environment is a big factor....
100 feet in warm clear still water is much less of a challenge than 50 feet in cold murky moving water.

Recently we had a problem 130 feet down in cold murky moving water 16 minutes into the dive.

Solomon I just wasted half an hour fiddling with this post and just about deleted it anyway... but I'm going to send it with the hope that it will do some good.

 

[Solomon]

I appreciate that and understand the narcosis point you are making. I was being too simplistic regarding narcosis issue. Of course I understand the effects of narcosis are gradual and most everyone has some impairment at 100 feet (even though it may not be readily apparent) but the same could be said at a depth of 80 feet as well. When I was talking about being narced I was referring to the very noticeable impairment. I have been there and immediately ascended several feet. For me I know that feeling and do not continue at that depth. I also am aware that the depth this happens can change from dive to dive. I would be interested in breathing a helium mixture at depth to see the "unoticeable" or "nonapparent" narcosis effects. Sounds like it could be interesting. Also, as you mentioned the conditions and the amount of task loading are factors to consider when diving "deep" on air. That was what I meant when talking about the dynamic factors involved in every dive (including many others).

 

[kodiak]

I alway thought that it was the amount of time you spent at depth that made it a decomp dive,not just how deep you go.

 

[Ari]

Sometimes shalower and sometimes deeper. depends on the mood, general feeling, partner, site etc.

Sorry for not getting into the very lively discussion.

Ari

 

[WreckWriter]

Originally posted by kodiak
I alway thought that it was the amount of time you spent at depth that made it a decomp dive,not just how deep you go.

It's a combination of both. The shallower you are, the longer you can stay before required deco, the deeper you go, the sooner you get into required deco.

Tom

 

[WreckWriter]

Originally posted by Uncle Pug
1. Narcosis does not hit at a certain depth above which you are uneffected. The effects of narcosis are progressive as you go deeper.

2. As depth increases so does the skill level needed to safely dive that depth. While 100 feet is not a magical number it is easy to remember and forms a benchmark for advancement

3. Every dive is a decompression dive and a dive in the 100-130 range is more so than most realize. The NDL time limits are not magic numbers either and you begin to incur a nitrogen load as soon as you go below the surface... and the deeper you go the faster you take on gas. A problem that develops 130 feet down and 10 minutes into the dive is a serious problem.

However I will add that environment is a big factor....
100 feet in warm clear still water is much less of a challenge than 50 feet in cold murky moving water.

All excellent points Pug. Narcosis is progressive but like Solomon said there is a point at which you "feel narced". That points varies from person to person and from day to day, influenced by such factors as temperature, work load, general health and well being.

NDLs are definately not magic. Most of the folks I've known who got bent got there on dives between 80-100'.

Tom

 

[Uncle Pug]

Originally posted by WreckWriter
like Solomon said there is a point at which you "feel narced". That points varies from person to person and from day to day, influenced by such factors as temperature, work load, general health and well being.

Exactly... some days on some dives it is harder to detect... but it is still there... that is why understanding the fact without the feeling is important to safety... dealing with a dive on the basis of its narcotic depth and not on the basis of your fickle feelings.

NDLs are definately not magic. Most of the folks I've known who got bent got there on dives between 80-100'.

That is a stinker... why do you think that is the case?