hand signals from diver to boat (in clear water)

[Tigerman]

So you rather surface with more than twice the gas you need in your tank and have the buddy drown than get yourself safely up and have the buddy bent IF (s)he runs into an issue on the way up?
Hell, Id rather spend the night in the chamber with the idiot than leave it drowned on the bottomn of the sea, but thats just me...

 

[kwinter]

Anyone who insists that a recreational dive can NEVER turn into a deco dive by accident just hasn't been diving long enough, or in difficult conditions. It shouldn't happen, but it does. And some of the examples given are spot on. But exceeding NDL by a minute or 2 is no problem. First, most computers will clear any required deco as you ascend, as long as you do so slowly. Second, the "safety stop" is a built in 3-5 minute unnecessary deco stop. Most computers that exceed NDL do not calculate that you now need a 2 minute stop at 3 meters IN ADDITION to your 3 minute stop at 4.5 meters. So your standard safety stop should clear any unintentional deco.

So in general, I have to agree with Mike.D in most regards. But I strongly disagree about his early post. Carrying 2 SMBs of different colors is neither standard nor common. And I do know a couple of boats that request different colors, with one color being for "diver on the line and might need help" while the other means there is some artifact or something being raised. But those are the exceptions. Most people I know carry one, and those that carry 2 are often the same color. Don't assume something is standardized. Talk about it before the dive.


iPhone. iTypo. iApologize.

 

[rivers]

So you rather surface with more than twice the gas you need in your tank and have the buddy drown than get yourself safely up and have the buddy bent IF (s)he runs into an issue on the way up?
Hell, Id rather spend the night in the chamber with the idiot than leave it drowned on the bottomn of the sea, but thats just me...

It sounds harsh, but I'm not going to risk myself because someone's done something stupid. I've marked the area, I've sent up (and secured) my blob with note attached, so hopefully someone is on their way down. Most boat skippers in the UK will know something is wrong if a blob is up and it's not moving. I will do what I can, but I'm not going to risk sending myself to a chamber.
Minimum gas in twins 12s on a 30m dive with no incurred deco is 50 bar by the way. If I have 10 minutes of deco to do at 6m, I'm looking at about 80 bar, so it's quite a lot of gas I have to use.
But, I repeat, I will not risk my own health and safety because of someone else's stupidity. There is only so much you can do. And rule number one of a rescue: Don't make a second victim. If there is a chance I will end up in the pot because I've had to blow off deco due to not having enough gas, it's not a risk I'm willing to take.

Also, if the diver is well and truly stuck, the priority should be getting them gas. there is tons of gas on the boat, get it sent down.

 

[Tigerman]

I totally agree gas is the most important, however...

You've decided to leave the buddy down there and ascend alone, you've shot your blob and waiting for gas (in an ideal world). Why do you still calculate gas needs for 2 people, you are now a solo diver. What you need to make sure is that your gas is enough to secure your own ascent, not the buddy you've left?

 

[rivers]

I totally agree gas is the most important, however...

You've decided to leave the buddy down there and ascend alone, you've shot your blob and waiting for gas (in an ideal world). Why do you still calculate gas needs for 2 people, you are now a solo diver. What you need to make sure is that your gas is enough to secure your own ascent, not the buddy you've left?

Unless I know for certain gas is on it's way down, i'm going up at minimum gas. I am of no help on the bottom if he is well and truly stuck. If he goes OOG, and he well may(he is panicked and stressed), he's going to be even more stressed if there isn't enough gas on ascent. Priority should be to get him gas. If that means going to the surface myself to make sure it's on its way down, then that's what has to be done. No one wants to leave a buddy, especially one in distress, behind. but there is a point where you will need to make a decision, and neither choice is ideal.

 

[beanojones]

Correction, in the PADI world, a recreational dive cannot be planned as a deco dive. I can think of at least 2-3 agencies off the top of my head that teach deco at a recreational level

That is an excellent point, but..

It is correct info as far as what the agencies espouse, but a deco dive is a dive in an overhead environment. Lots of agencies make mistakes, and have inconsistencies for historical reasons. An agency that allows overhead environment diving without redundancy is wrong and PADI fits nicely in this group but for different reasons, as talked about in this thread:

http://www.scubaboard.com/forums/basic-scuba-discussions/486683-wreck-penetration-queuing.html

The degree to which an agency epsouses diving in overhead environment without full redundancy and advanced training is the degree to which that agency is trying to serve too many masters (usually members from way back).

They are also often agencies which still base their repetitive dive tables on the old US Navy deco tables or the equivalent which is the reason they have to address deco diving at all. Without, unfortunately, actually ensuring that the divers they train were the sort of exceptional physically fit specimens that the Navy Divers were, or ensuring that their divers were fully supported with surface deco chambers, on site medical staff, etc.

PADI also mistakenly allows overhead environment diving on the recreational level, for different historical reasons: they offered these Cavern and Wreck classes as a money grab before they decided to go ahead and actually have a technical training side, and they don't want to revoke training credentials of members from way back.

Again, breaking/losing a mask happens often in diving. It is irresponsible to teach deco diving/overhead environment diving without requiring redundancy because divers without masks cannot do even see their SPG let alone their computers/tables. Only allowing direct access to the surface makes it safe to dive without a backup mask.

It's irresponsible to dive in, or allow diving in, overhead environments (wreck, cave, deco) without redundancy and advanced training, or experience, when the blowback can land on others heads. Many people do the diving, many instructors train in overhead environments, and as you point out there are even some agencies who are wrong on this issue, PADI among them.

The biggest issue here for me really is, diving off a boat. If someone wants to do solo non-rendundant deco dives from shore, then that is kind of their own deal. But diving on a boat owned by a company, with a captain, is necessarily something different. Most insurance coverage has specific exclusions/inclusions for various activities.

 

[kafkaland]

I just read this with my mouth agape. Do people like this really exist, or are these hyperbolic fish stories with just a kernel of truth? I'm still new to the sport and haven't encountered anyone like that yet - and if such a person exists, I hope I will never have the misfortune of diving with him.

They are the accomplished bad diver:
http://www.johnchatterton.com/2013/03/19/accomplished-bad-divers/

That article should be required reading for anyone thinking deco withOUT tech training is OK. From a preofessional's viewpoint, it simply endangers the industry as a whole.

 

[rivers]

That is an excellent point, but..

It is correct info as far as what the agencies espouse, but a deco dive is a dive in an overhead environment. Lots of agencies make mistakes, and have inconsistencies for historical reasons. An agency that allows overhead environment diving without redundancy is wrong and PADI fits nicely in this group but for different reasons, as talked about in this thread:

Who said the agencies didn't have a redundancy requirement?

GUE Rec 3 equipment requirements:
The GUE base equipment configuration is comprised of:

1. Tanks/cylinders: students may use a single tank/cylinder with a K-, H-, or Y-valve. Students may also use dual tanks/cylinders connected with a dual-outlet isolator manifold, which allows for the use of two first-stages. Consult course specific standards and your instructor to verify size requirements.
2. Regulators:
   • Single tank: one second-stage regulator must supply a 5 to 7 foot/1.5 to 2 meter hose (2 meter long hose is required for all cave classes). The first stage must supply a pressure gauge, inflation for the buoyancy compensator (BC), and a means to inflate a drysuit where applicable.
   • Double tank: one of two required first stages must supply a pressure gauge and provide inflation for a drysuit where applicable. The other second stage must supply a 5 to 7 foot/1.5 to 2 meter hose and an inflation source for the BC.
3. Backplate system:
   • Should be held to the diver by one continuous piece of webbing. This webbing should be adjustable and should use a buckle to secure the system at the waist.
   • A crotch strap is attached and looped through the waistband so as to prevent the system from riding up a diver’s back.
   • The continuous webbing should support five d-rings;
     • The first placed at the left hip
     • The second placed in line with a diver’s right collarbone
     • The third placed in line with the diver’s left collarbone
     • The fourth and fifth are placed on the front and back of the crotch strap where divers plan to use advanced equipment like DPVs.
   • The harness below the diver’s arms has small restrictive bands to allow for the placement of reserve lights. The webbing and system retains a minimalist approach.
4. Buoyancy compensation device (BC):
   • A diver’s BC is back-mounted and minimalist in nature.
   • It is free of extraneous strings, tabs, or other material.
   • There are no restrictive bands or restrictive elastic affixed to the buoyancy cell.
   • Wing size and shape is appropriate to the cylinder size(s) employed for training.
5. At least one time/depth measuring device.
6. Wrist-mounted compass.
7. Mask and fins: Mask is be low-volume; fins are rigid, non-split
8. At least one cutting device.
9. Wet Notes.
10. At least one surface marker buoy (SMB) with spool per diver.
11. Exposure suit appropriate for the duration of exposure.
    
12. 
    
    1. plus
13. GUE double tank configuration
14. Primary and back-up lights
15. Decompression cylinder
16. Small argon regulator and bottle (if appropriate for local conditions)
17. Back-up mask
    

Looks like there is some redundancy there. I see manifolded twins and a deco stage, plus back-up mask, spools, dsmbs, etc. Granted it's GUE so the entry requirements onto the course are bit more stringent than other agencies.

BSAC also introduce mandatory deco at sports diver level. Not sure of the equipment requirements, but I know in my club, you're not doing any sort of deco unless you have some sort of redundancy. and a 3 litre pony won't cut it.
I will respond to other bits in a separate post as this font is really annoying me...

---------- Post added July 4th, 2014 at 01:32 PM ----------

That is an excellent point, but..

It is correct info as far as what the agencies espouse, but a deco dive is a dive in an overhead environment. Lots of agencies make mistakes, and have inconsistencies for historical reasons. An agency that allows overhead environment diving without redundancy is wrong and PADI fits nicely in this group but for different reasons, as talked about in this thread:

http://www.scubaboard.com/forums/basic-scuba-discussions/486683-wreck-penetration-queuing.html

The degree to which an agency epsouses diving in overhead environment without full redundancy and advanced training is the degree to which that agency is trying to serve too many masters (usually members from way back).

They are also often agencies which still base their repetitive dive tables on the old US Navy deco tables or the equivalent which is the reason they have to address deco diving at all. Without, unfortunately, actually ensuring that the divers they train were the sort of exceptional physically fit specimens that the Navy Divers were, or ensuring that their divers were fully supported with surface deco chambers, on site medical staff, etc.

PADI also mistakenly allows overhead environment diving on the recreational level, for different historical reasons: they offered these Cavern and Wreck classes as a money grab before they decided to go ahead and actually have a technical training side, and they don't want to revoke training credentials of members from way back.

Again, breaking/losing a mask happens often in diving. It is irresponsible to teach deco diving/overhead environment diving without requiring redundancy because divers without masks cannot do even see their SPG let alone their computers/tables. Only allowing direct access to the surface makes it safe to dive without a backup mask.

It's irresponsible to dive in, or allow diving in, overhead environments (wreck, cave, deco) without redundancy and advanced training, or experience, when the blowback can land on others heads. Many people do the diving, many instructors train in overhead environments, and as you point out there are even some agencies who are wrong on this issue, PADI among them.

The biggest issue here for me really is, diving off a boat. If someone wants to do solo non-rendundant deco dives from shore, then that is kind of their own deal. But diving on a boat owned by a company, with a captain, is necessarily something different. Most insurance coverage has specific exclusions/inclusions for various activities.

Maybe I've been living in the UK too long and their way of thinking has rubbed off on me... Diving is approached very differently over here outside of the PADI world (although PADI does have a foothold and it's always fun to get into diving chats with some of the hardcore PADI folks).
The way PADI approach deco is that it's the bad thing that needs to be avoided at all costs in recreational diving. Because of this, you have a whole host of divers who are petrified to go into deco or don't know what to do if they find themselves with a ceiling.
Other agencies approach it in a different manner, basically saying once you have sufficient experience under your belt, there is nothing wrong with doing a few minutes of deco in the recreational depth range, and here is how you do it safely. this is what you need, this is how you plan for your gas, etc. It's not something to be scared of or even something to aspire to, but it is another tool in your toolbox to utilise if you so choose.
I myself am a recreational diver who on occasion (most of my sea dives in the 30-35m range) will choose to do 10-15minutes of deco. I only have a 35m ticket, but I also have an accelerated deco ticket (I find deco boring), and next month, I have GUE Rec 3 (which will give me 40m and a trimix ticket). Again, every cert I have is a recreational cert. All of my diving is in recreational ranges, and I don't know that I will go beyond them.

To comment on your other big issue: solo diving off of a boat. Come to the UK, it happens all the time. The only thing you need is redundancy (pony, twinset, etc). I was on a boat 2 months ago and my mate had a catastrophic drysuit failure (dump valve fell off). I called the dive as well, but skipper would have been happy for me to continue the dive solo. And, if conditions were better (vis was pants, and it was dark at 6m, never mind at 15m), I most likely would have continued the dive on my own. It was a shallow wreck (15m), that I knew well. Now if it were a 30m wreck, even with perfect conditions, I wouldn't have even contemplated it. A UK dive boat is transportation to and from the site. You get a briefing from the skipper, and he shots the wreck if it's not permanently shotted, and you get a cup of tea, coffee, hot chocolate or soup on return.

 

[ratchet04]

I just read this with my mouth agape. Do people like this really exist, or are these hyperbolic fish stories with just a kernel of truth? I'm still new to the sport and haven't encountered anyone like that yet - and if such a person exists, I hope I will never have the misfortune of diving with him.

You won't; he died being an accomplished bad diver...

 

[Skittl1321]

I have a question about the original post that doesn't seem to be addressed.

you ran out of air would you swim up to the boat, yell for another tank & go back down quickly to 3 m (or deeper?) to finish the deco?

Our instructor (a tech diver) told us that the current line of thinking was once you got out of the water you stayed out of the water. Put yourself on oxygen if you need to, but don't jump back in to meet an obligation.

Did I misunderstand him, and he just meant no in water recompression if you think you are already bent; or that in this case to you wouldn't go get another tank and hop back in to finish your deco time.


(For the record- I really do not plan on ever going into deco. I watch my computer like a hawk.)