Diving Without Depth/time only SPG

[tracydr]

Back in the early 70's, there was a guy that would dive with only a SPG. I did a deep ( 150+ ) dive with him. BTW, he could freedive to 100+ feet and spear three fish on one breath. He would tow his small dory around the island. He would fight off the sharks if they wanted the fish on his spear.

He would simply go as deep as he wanted or could til his SPG hit 2000 PSI, then he would head up.

Amazingly, he is still alive. He is a legend in his own time. He was an animal.

Would I recommend this practice? NO!

However, I did learn from it. Head up when your tank hits 2000 PSI on a 3000PSI tank. Do not continue your decent.

If new divers followed this procedure, then they would stay within their 40' to 60' depth limit.

That is not to say, keep going down if you still have the air ( gas ). You need to have a dive plan and stay within your limits.

You need a dive computer and know how to use it.

We actually have been requiring dive computers on our trips since 1990. On a once in a Once-in-a-lifetime trip, we highly recommend that you dive with two computers and redundant air supply monitors ( SPG, Air-integrated computers ).

Wow, since 1990? I trained in 1995 and we did our training entirely with tables, bottom timers/depth gauges. Since I was a poor medical student/soldier, I didn't get a computer until around 2000. I dove tables until then. Amazingly, I survived! Tables can be very safe. Part of the extra conservatism comes from the assumption of a square profile. Of course, you do lose bottom time and I certainly dive two computers now, especially on dive trips. But, I'm amazed you had this rule in 1990 when dive computers were still fairly new and relatively expensive. ( from my recollection, anyway).

 

[danvolker]

Yeah but... if you followed the Navy Tables (and the directions that came with them) then they were not all that aggressive.


For example, didn't you HAVE TO go to the next greater depth and time increment when spearfishing (since it was a strenuous dive). Also, weren't many of your dives back then floating high above the bottom and dropping down for short durations to get a fish... thus, the square profile assumption was another significant factor in making the tables conservative. I know i can dive for much longer on my computer than on Navy tables for the typical dives that I do.

Good point DD....Back in the 70's, most of us were spearfishing.....and the tendancy was to "hunt" around 20 feet off the bottom, or maybe even 10 feet off the top of a big ledge.....and since the tables then had you compute to the deepest depth, this was a large addition of safety margin. I don't know anyone back then, or in the 80's and early 90's with Frank Hammett, that ever calculated a different depth based on our dives being strenuous....And I will say, keeping up with Frank on a spearfishing dive would have me, or anyone else able to be with him, pretty much swimming at a maximum cruise speed spearfishing pace, on much of the dive....which was certainly strenuous....However....Every single diver doing this with Frank was very athletic, which I still maintain is a sub-population of the population the tables were based on, and one in which there was TOO much fudge factor and conservatism built in to it--meaning there was no reason to add the extra measure of conservatism for a strenuous dive.

If I did not already have several computers ( some were presents) and had to consider what I would buy, it would be a depth guage with timer..... I would absolutely NOT consider a computer. Not for me. Not for the way I dive Palm Beach....which certainly does have plenty of multi-level potential, but it is just too easy to average this at a safe depth....It does not require thousands of dollars of computer for this...For a few hundred dollars have some one teach you Ratio Deco A much better investment !

 

[beaverdivers]

Amazingly, I survived!

Just think of all that bottom time you missed.

We did consider the cost of using a dive computer before requiring them. At $10/day or $50/week, I believe any diver could afford it. If they understood it's value.

 

[danvolker]

Dan, do you use redundant gauges or devices; watches, bottom timers, j values, SPG, depth gauges?

I have a depth guage/timer ( actually a Cressy Eddy in gauge mode) , I have one analog pressure gauge. I also dive with a buddy which is my redundant timer, and redundant depth gauge. If a had my depth guage/timer fail half way through a dive, I would still know the depth range of the dive, and would know pretty close to how much longer I would want to stay down, based on my pressure gauge....but would also have the buddy's timer.....
Since 1972 I have never had a watch or depth guage/timer failure, this is well over 10,000 dives. In other words, I consider redundancy as a need here, silly. If I have a failure like this on a recreational dive, I may or may not decide to ascend with buddy, based on several criteria. Advice to others would certainly be to call the dive, but that has more to do with being able to read all the factors involved, and the challenge level of the recreational profile....A tech dive is different, that would be cause to call the dive..

If you are doing a 100' dive, then do you head directly to the surface at 60'/min. after 20 minutes of bottom time.

I could, easily and safely on Nitrox....and in the past, have done this on air countless times in the 70's and 80's.
It is not a behavior that is consistent with the Team style of diving I now practice, so today that is not a way I handle a 100 foot dive.
I do not know for a fact that every buddy I may have with me, can do the old time profiles safely, so the smart thing is to use our WKPP or GUE tables now, depending on who I am diving with.
Also, I made a commitment to adopt the GUE system, and I have.....my point here, is that there is no way I am going to forget the history, and the realities of divers NOT getting hurt with the 60 foot per minute ascents in the old days. ...Functionally what this means....imagine a diver in my group or one in sight is injured, and needs help ASAP. I don't have the constraints of the computer on how long it will take me to reach the surface if I need to help someone--whether getting them up right away, or getting the boat on site, whatever. I know I can go up much faster than the computer will indicate, and it will result in no injury to me....fear of an injury that would not occur, is a poor reason to refuse to assist an injured diver with the speed their emergency requires.

In 1989, I had a group diving Bloody Bay Wall off Little Cayman. Our protocol was that you were either on the dive tables or a dive computer. Midway through the trip, one of our divers using dive tables said " This dive was great, but all you computer divers were down an hour and I had to be back on the boat in 30 minutes! "

Dive table divers wanted to shadow divers with computers. Our protocol is every diver must have their own computer.

After that trip, we decided to draw the line and require dive computers. The decision was not retail driven, it was driven by the desire to spend more time U/W with less risk.

If you figure your cost/minute of diving, a dive computer will pay for itself in one dive trip.

Well, my depth timer/gauge is a computer, so I am covered
The ratio Deco option also did not exist in 1989


And then there is a diver buying an inexpensive computer, AND knowing the tables for any given dive....I like this direction for most divers...In this I am sure I am in total agreement with Beaverdivers

 

[adurso]

Computers are a tool, not a necessity.

Unfortunately people are putting more reliance on the hardware then themselves.

Say an inflator is sticking?

What do most people do?

 

[chrpai]

Probably what most people do when the accelerator sticks in their car. Have an accident and blame the manufacturer.

Me, I'd just hold it up with my left hand as start venting while I use my right hand to pull the supply line off. Then orally inflate as needed.

 

[danvolker]

Probably what most people do when the accelerator sticks in their car. Have an accident and blame the manufacturer.

Me, I'd just hold it up with my left hand as start venting while I use my right hand to pull the supply line off. Then orally inflate as needed.

Isn't there a one thousand dollar computer that monitors the inflation of your BC, and will automatically handle the inflator emergency for you? I mean, why be forced to learn how to do something, when it can be done for you with no thinking on your part.... right ?

 

[CT-Rich]

I was certified in 1980 and learned table diving, buddy breathing and my first tank had a J-valve. I never had a problem either doing it that way. I do know that at eighty feet judgement gets mildly impaired, even before you become consciously narc'd. A dive computer will help avoid the need to get caught up in tasks that may distract you from other important tasks. Think of it as your sober friend, he is going to give you advise, you can take it or leave it. I never had a problem going up following the smallest bubble rule, to be honest, I still do, sometimes. But importantly, computers saves me from mental math that I was never super good at anyway. I could balance my check book with a scratch of paper and pencil, but a calculator is going to help me avoid errors, so why not? The same goes for a divecomputer... Why not?

 

[Nemrod]

Is this a safe practise?
Give your opinion!

Diving when I was a child, most of the time on the flats the water was barely 10 feet and maybe 25 at max. We would dive without anything though most of our tanks had J valve reserves. We would suck the tank flat and then hold our breath until our eyeballs bulged out trying to stay down longer. Somehow we survived so it must not have been all that dangerous, of course, maybe 12 year olds in the old days were better divers than grown up PadI divers today, dunno. We felt safe enough, then, safety is way overrated if it gets in the way of living.

By "anything" I mean we did not have depth, time, spg, BC, nothing.

N

 

[chrpai]

Probably what most people do when the accelerator sticks in their car. Have an accident and blame the manufacturer.

Me, I'd just hold it up with my left hand as start venting while I use my right hand to pull the supply line off. Then orally inflate as needed.

Here's another one:

Video - Breaking News Videos from CNN.com
http://www.cbsnews.com/8301-505245_162-57500082/stuck-accelerator-takes-woman-on-ride-over-110-mph/

HMmm.. Jeesh. Is it really that hard?