Bad scuba advice you've received

[lermontov]

(after you've done your penetration dive and still got some gas left )

'lets have a quick look in here....'

 

[Nick_Radov]

How's that a problem? My buddy surfaced with 500psi regularly for deeper dives cus even with a cave-filled HP100(4200psi) and low SAC, my buddy can only stay 15-20mins at 120ft. That's too short of a dive and 15min is far from enough to finish seeing a 200ft long shipwreck. If surface more than 500psi, it will be a dive that's too short to be worth it. For shallow dives(60ft), I ask my buddy to signal me at 500 psi(Safety stops) and surface at 200 psi. This is only for open water tho. No overhead.

If your buddy can't do 20 minutes at 120ft on a jacked HP100 without violating minimum gas then he doesn't actually have a "low" SAC. Average at best.

There's nothing magic about surfacing with 500psi, or any particular pressure. We need to do proper gas planning so that at maximum depth you have enough reserve gas to deal with an emergency and then make a safe ascent while sharing gas with your buddy. Minimum gas in an HP100 at 120ft is going to be around 1200psi for most divers so you would need to start the ascent at that pressure. But that's just a rough estimate, every diver needs to calculate it for themselves. If nothing goes wrong then you'll be back on the surface with well over 500psi.

In general going much deeper than 100ft on a single tank is not a real smart plan. The issue isn't just gas volume but lack of redundancy. You can do it safely if you have really good buddy skills and are ready to share gas at any moment but it's far better to have redundant gas supplies in the form of doubles with an isolation manifold.

 

[Wibble]

My buddy surfaced with 500psi regularly for deeper dives cus even with a cave-filled HP100(4200psi) and low SAC, my buddy can only stay 15-20mins at 120ft. That's too short of a dive and 15min is far from enough to finish seeing a 200ft long shipwreck. If surface more than 500psi, it will be a dive that's too short to be worth it.

35m/120ft has an air NDL of 14 minutes (PADI RDP). With nitrox 30% it’ll be ~20mins.

The solution is simple. Develop your skills and experience then learn ANDP —Advanced Nitrox and Decompression Procedures.

Then you can dive for a lot longer. 45 minutes or longer on the wreck is easily achievable with the right planning and redundancy.

Free your mind from the constraints of recreational no-decompression limits!

 

[doctormike]

How's that a problem? My buddy surfaced with 500psi regularly for deeper dives cus even with a cave-filled HP100(4200psi) and low SAC, my buddy can only stay 15-20mins at 120ft. That's too short of a dive and 15min is far from enough to finish seeing a 200ft long shipwreck. If surface more than 500psi, it will be a dive that's too short to be worth it. For shallow dives(60ft), I ask my buddy to signal me at 500 psi(Safety stops) and surface at 200 psi. This is only for open water tho. No overhead.

I don't like the idea of PLANNING to surface at 200 PSI. SPGs can be inaccurate at low readings, an emergency on the surface might require gas not just for breathing but for inflating a BC. And of course, if you are planning such a thin margin of safety, you will have an issue if you have any sort of problem near the end of the dive like a blown LP hose or a free flow.

So if the extra 300 PSI makes the difference between an enjoyable dive for him and one that's "not worth it", then he or she needs to carry more gas. Doubles, stage bottle, etc..

That's the reason that I originally did OC tech training... so that I would have more time at depth at that range.

 

[johndiver999]

I don't like the idea of PLANNING to surface at 200 PSI. SPGs can be inaccurate at low readings, an emergency on the surface might require gas not just for breathing but for inflating a BC. And of course, if you are planning such a thin margin of safety, you will have an issue if you have any sort of problem near the end of the dive like a blown LP hose or a free flow.

So if the extra 300 PSI makes the difference between an enjoyable dive for him and one that's "not worth it", then he or she needs to carry more gas. Doubles, stage bottle, etc..

That's the reason that I originally did OC tech training... so that I would have more time at depth at that range.

No, that is not correct. Gas from the tank is not required to inflate the BC at the surface. This is the kind of thinking that gets people in trouble.

 

[doctormike]

No, that is not correct. Gas from the tank is not required to inflate the BC at the surface. This is the kind of thinking that gets people in trouble.

Yes, it is not REQUIRED. But if you are attempting to rescue an injured, panicked or unconscious diver at the surface, you are going to have a MUCH better day if you just lean on the inflator button rather than trying to simultaneously keep them afloat and orally inflate their BC. Have been there.

Empty tank on the surface is OK? That's the kind of thinking that gets people in trouble.

 

[Wookie]

I'm really happy that this is the BAD ADVICE thread, because there is some really stupid advice being touted.

 

[johndiver999]

I agree some bad advice. The doctor previously indicated that tank air may be required in an emergency on the surface to inflate the BC. This is very bad thinking in an emergency and he has corrected the statement.

It is critical that you plan for oral inflation at the surface of the BC in an emergency. If there is air in the tank then great, but incorrect thinking in an emergency at the surface can kill people.

Last week had a buddy run out of air on bottom on solo dive, he had disconnected the inflator hose from bc during dive due to a leak. then when he wanted to come up, he forgot about orally inflating his BC. It was very bad thinking, on top of some bad choices. Luckily he rode the scooter up and did not get bent. the point about incorrectly assuming you need tank air to fill the BC is not a trivial point.

 

[doctormike]

If there is air in the tank then great, but incorrect thinking in an emergency at the surface can kill people.

Gotta say, this is one of the silliest arguments that I have had here, and that's a pretty high bar.

The idea that being aware of the option of filling a BC with the inflator of an injured, panicked or unconscious diver is not only dangerous, but potentially lethal, is not an idea that I agree with.

the point about incorrectly assuming you need tank air to fill the BC is not a trivial point.

I don't assume that you need tank air to fill a BC. I know that when things fall apart, its a far quicker and easier to inflate an injured diver's BC with tank air.


And once more, to quote Mike Tyson on the concept that enough training and practice will always result in calm, cool, optimal performance, making reserve gas unnecessary: "Everyone has a plan until they get punched in the mouth."

 

[johndiver999]

Gotta say, this is one of the silliest arguments that I have had here, and that's a pretty high bar.

The idea that being aware of the option of filling a BC with the inflator of an injured, panicked or unconscious diver is not only dangerous, but potentially lethal, is not an idea that I agree with.





I don't assume that you need tank air to fill a BC. I know that when things fall apart, its a far quicker and easier to inflate an injured diver's BC with tank air.


And once more, to quote Mike Tyson on the concept that enough training and practice will always result in calm, cool, optimal performance, making reserve gas unnecessary: "Everyone has a plan until they get punched in the mouth."

You initially indicated that tank air is REQUIRED for inflation at surface. That was erroneous thinking, glad you corrected yourself.