Equipment for Adv Nitrox and Deco Proc

[nereas]

Umm...what he was saying was that you remove RB "from the top" and then dive "rule of x" on what´s left which is less agressive than just diving "rule of x"...

...

That seems to be redundantly redundant, however.

If a dive is that hazardous, it probably should not be attempted by anyone other than professional oil rig divers.

Professional divers also have the valid option of using CCRs, which solves this problem even better.

Amateurs probably should never be using CCRs however. I know this would cut into Megalodon sales, however, and the Megalodon enthusiasts are going to kick and scream as well.

 

[DA Aquamaster]

I have had my mask knocked off in real life............mask removal during training to me is not that far fetched.

I have read about Mike Ball Charters divers clipping to a reef hook, then swinging into the current and having their masks ripped off by the current, in Peliliu. And since they were beginners, they had no spare mask nor sharp knife to cut the reef hook line. A comedy of lethal errors.

When I first got certified, one of the sites for the initial dives was below a hydro electric dam. With all seven tunnels open a 5 to 7 kt current was common and if you were fairly close to the dam you could encounter some impressive interplay between the current and the 1 or 2 knot backwash running upstream closer to shore. In fact that was part of the fun as you could swim toward the center of the channel and drift down then swim closer to shore and drift back up then drift down again.

A 5 to 7 kt current is enough to rip the mask off your if you turn sideways to the current, but even newly minted OW divers of that era understood enough to anticipate and avoid having that happen, even with the high profile masks of the time. It became a favorite spot due to good viz and the ability to fly over the bottom and I dove there hundreds of times over the next decade. I completely flooded my mask a couple times but never lost it.

In my opinion, it makes more sense to train how to prevent losing your mask (strap styles and low profile masks that prevent loss, putting the strap under the hood, inspecting the strap for weather checking on a regular basis, etc) than to train to lose it and if you take the former approach, losing a mask is far fetched. In fact "losing" it repeatedly under water in training is a PITA as you have to remove or pull back the hood each time. After awhile the student will get annoyed and it will just get worn on top of the hood and you actually create a practice for the student that increases the potential for mask loss rather than reduces it. You end up training to resolve a situation largely created by the focus of the training on a previously preventable problem. The artifical nature of mask "loss" in training does not promote a "train like you fight, fight like you train" mentality.

I carry a back up mask in a hip pocket on overhead dives, I even practice with it, and the strap is configured differently not for loss prevention but rather for ease of replacement and reliability. But to be honest it is not something I ever think I'll have to use and if I did, I'd pay serious attention to the failure that led to mask loss in the first place.

 

[Bismark]

When I first got certified, one of the sites for the initial dives was below a hydro electric dam. With all seven tunnels open a 5 to 7 kt current was common and if you were fairly close to the dam you could encounter some impressive interplay between the current and the 1 or 2 knot backwash running upstream closer to shore. In fact that was part of the fun as you could swim toward the center of the channel and drift down then swim closer to shore and drift back up then drift down again.

A 5 to 7 kt current is enough to rip the mask off your if you turn sideways to the current, but even newly minted OW divers of that era understood enough to anticipate and avoid having that happen, even with the high profile masks of the time. It became a favorite spot due to good viz and the ability to fly over the bottom and I dove there hundreds of times over the next decade. I completely flooded my mask a couple times but never lost it.

In my opinion, it makes more sense to train how to prevent losing your mask (strap styles and low profile masks that prevent loss, putting the strap under the hood, inspecting the strap for weather checking on a regular basis, etc) than to train to lose it and if you take the former approach, losing a mask is far fetched. In fact "losing" it repeatedly under water in training is a PITA as you have to remove or pull back the hood each time. After awhile the student will get annoyed and it will just get worn on top of the hood and you actually create a practice for the student that increases the potential for mask loss rather than reduces it. You end up training to resolve a situation largely created by the focus of the training on a previously preventable problem. The artifical nature of mask "loss" in training does not promote a "train like you fight, fight like you train" mentality.

I carry a back up mask in a hip pocket on overhead dives, I even practice with it, and the strap is configured differently not for loss prevention but rather for ease of replacement and reliability. But to be honest it is not something I ever think I'll have to use and if I did, I'd pay serious attention to the failure that led to mask loss in the first place.

I think you are missing the point of the primary purpose of removing the mask in training. Re-read posts 73 and 74.

You are right in that it would be a rare to "lose" a mask in an actual dive. A couple of practise sessions with removing and replacing a mask should solve the actual problem. However, maskless drills work a a few other levels as well. For beginning technical divers, the very first thing to go out the window when experiencing some sort of problem, is buoyancy control. Unfortunately, as others have pointed out, it is also possibly the most critical skills any technical diver needs to possess. One of the primary methods we all use for establishing our position in the water column is a visual reference supplied by our eyes. Remove this reference and you need to be keyed in to the more subtle signals sent by your ears, sinuses, expanding volume of gas in your drysuit, etc. Taking a students mask away (or having them close their eyes or better yet, using a blacked out mask) is a way of requiring the diver to rely on, trust, and develop these smaller feedback references. This also helps the diver developing his/her blue water training where you might be able to see, but you have no idea, short of your gauges, where you actually are in the water column. The second point of removing the mask is to emphasize in training what can happen if your primary light goes out and you do not remove a secondary light quick enough. It is quite common to see a student continue working after you have shut off their primary light, and they are oblivious to this fact because they are operating in clear water. If they don't un-stow a back up light quick enough, in the real world they would be in a blacked out environment, so you remove their mask to emphasize this. Finally, removing a mask is a great task loading feature and will essentially create a "helpless" diver that must be managed by their buddy or buddies. It is also a great way to start the task loading process for a diver where you are interested in developing his/her decision making skills. EG: a diver following a line in a silted out environment bumps into something or gets kicked (following closely) and floods or loses his mask, does he or she immediately let go of the line to fix or replace their mask or do they recognize the primary importance of their guideline and continue on with no mask or a flooded mask?

In any case, I agree with you that you most likely are not going to lose your mask but their is a good deal of utility in removing a mask in training to develop other skills areas.

 

[String]

Ive had a mask dislodged but not removed on a dive. However i have also had the lens drop out of a mask on a dive which obviously meant it completely flooded.
If that had happened on a dive with a deco obligation without a spre it wouldnt have been able to see my gauges or exit safely.
Although rare, masks can break as well as just fall off.

 

[DA Aquamaster]

I think you are missing the point of the primary purpose of removing the mask in training. Re-read posts 73 and 74.

You are right in that it would be a rare to "lose" a mask in an actual dive. A couple of practise sessions with removing and replacing a mask should solve the actual problem. However, maskless drills work a a few other levels as well. For beginning technical divers, the very first thing to go out the window when experiencing some sort of problem, is buoyancy control. Unfortunately, as others have pointed out, it is also possibly the most critical skills any technical diver needs to possess. One of the primary methods we all use for establishing our position in the water column is a visual reference supplied by our eyes. Remove this reference and you need to be keyed in to the more subtle signals sent by your ears, sinuses, expanding volume of gas in your drysuit, etc. Taking a students mask away (or having them close their eyes or better yet, using a blacked out mask) is a way of requiring the diver to rely on, trust, and develop these smaller feedback references. This also helps the diver developing his/her blue water training where you might be able to see, but you have no idea, short of your gauges, where you actually are in the water column. The second point of removing the mask is to emphasize in training what can happen if your primary light goes out and you do not remove a secondary light quick enough. It is quite common to see a student continue working after you have shut off their primary light, and they are oblivious to this fact because they are operating in clear water. If they don't un-stow a back up light quick enough, in the real world they would be in a blacked out environment, so you remove their mask to emphasize this. Finally, removing a mask is a great task loading feature and will essentially create a "helpless" diver that must be managed by their buddy or buddies. It is also a great way to start the task loading process for a diver where you are interested in developing his/her decision making skills. EG: a diver following a line in a silted out environment bumps into something or gets kicked (following closely) and floods or loses his mask, does he or she immediately let go of the line to fix or replace their mask or do they recognize the primary importance of their guideline and continue on with no mask or a flooded mask?

In any case, I agree with you that you most likely are not going to lose your mask but their is a good deal of utility in removing a mask in training to develop other skills areas.

Its not a matter of missing the point, I understand the point. My point is it makes more sense to use a bit more creativity to create task loading that is a genuine possibility in the real world and that is much more realistic.

For example, one of my tech cert agencies required mask removal for a line drill in open water. No exceptions, it was policy. It makes sense to some degree as it simulates getting out of a cave with no back up light.

But in contrast in the PSD community, the same type of zero viz drill is simulated much more effectively with a piece of tin foil wrapped over the mask. The result is more effective as you get no visual reference at all and with a black skirted mask you get a near pitch black condition. It is much more realistic and better approximates the actual condition that may result in the real world. You can actually see a lot with no mask compared to blacked out mask.

You are not wrong to say there is some advantage to mask removal, I am just saying there are more effective ways to accomplish the same thing.

 

[Blackwood]

For example, one of my tech cert agencies required mask removal for a line drill in open water. No exceptions, it was policy. It makes sense to some degree as it simulates getting out of a cave with no back up light.

But in contrast in the PSD community, the same type of zero viz drill is simulated much more effectively with a piece of tin foil wrapped over the mask.

We just turned our masks around (slap strap over eyes).

 

[Meng_Tze]

....The artifical nature of mask "loss" in training does not promote a "train like you fight, fight like you train" mentality.

...

Maybe not (was not aware that that is a desired approach to training..), but I for one am glad it was part of my training.

 

[waterpirate]

I chose to purchase my own gear before travelling onward with training, for reasons stated earlier. While driving to work this morning I had a revelation on this topic.
We all drive cars, and have been doing so for many years, but no one in thier right mind would rent a tractor trailer and go take a driving course/road test to get a cdl liscense....
Moving to doubles should be the same mind set, get the gear, get a mentor, dive the gear alot in ndl, then training.
Eric

 

[Bismark]

Its not a matter of missing the point, I understand the point. My point is it makes more sense to use a bit more creativity to create task loading that is a genuine possibility in the real world and that is much more realistic.

For example, one of my tech cert agencies required mask removal for a line drill in open water. No exceptions, it was policy. It makes sense to some degree as it simulates getting out of a cave with no back up light.

But in contrast in the PSD community, the same type of zero viz drill is simulated much more effectively with a piece of tin foil wrapped over the mask. The result is more effective as you get no visual reference at all and with a black skirted mask you get a near pitch black condition. It is much more realistic and better approximates the actual condition that may result in the real world. You can actually see a lot with no mask compared to blacked out mask.

You are not wrong to say there is some advantage to mask removal, I am just saying there are more effective ways to accomplish the same thing.

You will note that in my comment I did mention a blacked out mask as being very useful and maybe even better. Personally, I think that until you get used to it, having your mask removed unexpectedly in cold water can add a fair bit of drama to a situation and would more accurately simulate what would happen if you were kicked by the person on the line in front of you whether in silted out conditions or not. Interestingly,I just returned from weeks of filming technical diving skills in the Red Sea and have on film two occasions where when 3 skilled divers were following a line with blacked out masks, someone accidentally kicked someone behind them, dislodging their mask. I imagine the team was happier with no mask in 30' of water than with their blacked out masks........

I think there is a place for maskless drills and a place for blacked out mask drills, and they both emphasize different skills. Unless it is pitch dark out, I am sure we could both agree that we can see reasonably well in the ocean without a mask. I can't read my gauges but I can see line and the shapes and colours of people and bigger objects. Removing my mask in warm water is pretty much a non event, however, I still catch my breath a bit when you do it in cold water.

 

[TSandM]

Honestly, one of the biggest lessons of having my mask removed multiple times was that I had darned well better OPEN MY EYES when it's off. That was worth a lot, and it seems to have taken quite a few masks yanks for me to have that solidly installed