500 psi on the boat?

[The Logic Theorist]

OK. So the boat asks for you to return with at least 500 psi. How many of you have ever had someone from the boat go around and check the gauges? Have any of you seen someone denied a second dive because they allowed their tank to get below the magic number? Besides, if they are my tanks, what do you care if I suck them dry?

I have had a dive op in Malta log the remaining tank pressure for each diver at the end of each dive. They did not deny anyone dives, but they were paying attention to how we were managing our gas, and I noticed the DM pay more attention to the guages of people who came back light on their subsequent dives.

I have also been told of charter boat operators that take divers to the Flower Gardens in the Gulf of Mexico denying subsequent dives for people who came back with too little reserve in their tanks or went into NDL time.

Regardless, I really don't understand why you'd want to plan to surface with empty tanks. It shouldn't take someone else forcing you to keep a reserve, you should take the initiative for your own safety.

 

[Zieg]

I
Regardless, I really don't understand why you'd want to plan to surface with empty tanks. It shouldn't take someone else forcing you to keep a reserve, you should take the initiative for your own safety.

Never said anything about returning with empty tanks. There just seems that alot of people believe that they absolutely have to return to the boat with no less than 500. I don't believe that getting back to the boat with 500 psi makes you a "safe" diver or for that matter, getting back with less that 500 psi makes you an "unsafe" diver.

 

[DBailey]

OK. So the boat asks for you to return with at least 500 psi. How many of you have ever had someone from the boat go around and check the gauges? Have any of you seen someone denied a second dive because they allowed their tank to get below the magic number? Besides, if they are my tanks, what do you care if I suck them dry?

I did two seperate trips with one resort/charter, and they logged in everyone's starting and ending pressures.

The pressure check was the first part of their roll call to make sure everyone was on the boat. The second part was an actual roll call before we pulled anchor.

 

[Sideband]

I'll bet you there are more than one certified diver who can't even do a doggy paddle or back float for 200 yards. These folks would be terrified without a reg or snorkel in their mouth.

Those people do not belong in the water diving.
If I am incapable of tying a knot or doing a single pullup, should I go rock climbing?

 

[Blackwood]

Never said anything about returning with empty tanks. There just seems that alot of people believe that they absolutely have to return to the boat with no less than 500. I don't believe that getting back to the boat with 500 psi makes you a "safe" diver or for that matter, getting back with less that 500 psi makes you an "unsafe" diver.

Aye. Getting back with something other than 500 psi is only meaningful if you intended to get back with 500 psi.

 

[rongoodman]

On the Caribbean Explorer in Saba last spring they logged our time of exit and ending pressure on every dive. (The numbers were handy to have after the trip for calculating SAC rates.)

 

[The Logic Theorist]

Never said anything about returning with empty tanks. There just seems that alot of people believe that they absolutely have to return to the boat with no less than 500. I don't believe that getting back to the boat with 500 psi makes you a "safe" diver or for that matter, getting back with less that 500 psi makes you an "unsafe" diver.

There's no need to put words in my mouth. I never said, nor suggested, that returning to the boat with 500psi was the sum total of what's required to be a safe diver.

If you planned for a 500psi reserve, and were forced to use some of it because of some unforseen contingency (leak, buddy out of air, lost getting back to the anchor line, etc), there shouldn't be a problem with that. That is, after all, why you plan a reserve. If, however, you planned to get back with 500psi and didn't for no reason, then you didn't dive your plan.

And again, I don't understand why you would plan to cut it any closer than that (note that you actually did say they're your tanks so who cares if you breathe them empty). What do you think is acceptable if you think 500psi is too much?

Finally, when you're on a charter boat, you are to some extent the responsibility of the Captain. They do have quite a bit of leeway to suggest arbitrary rules, and this seems to be one of them.

 

[Blackwood]

What do you think is acceptable if you think 500psi is too much?

Your post wasn't directed my way, but I'll answer anyway: It depends on the tanks, the divers, and the dive profile.

For example, if I'm on a leisurely dive to 50 feet, I'll surface with no less than 170PSI. To 130 (min deco), I'll surface with no less than about 450PSI. This is for double HP100s.

(edit: those are my off-the-top-of-my-head calculations of 'rock bottom' minus what I'd really use sans emergency).

 

[perdidochas]

I'm not sure where the get rid of the snorkel bit came in.

Cave/technical divers.

I both dive and snorkel and free swim with no gear. In terms of effort and fatigue, both breathing with a snorkel or from a regulator is easier than breathing directly from the mouth and you at least have a lower likelihood of swallowing water as well. As pointed out by an earlier poster, if you are in a high sea state and you are breathing through your regulator but you run out of air, the snorkel is much easier to use than constantly fighting to breath through your mouth. I know that I can float and slowly swim while snorkeling with very little effort. It takes more effort to swim without a snorkel for no other reason than that I need to rotate my head to take a breath. I am a fairly strong swimmer but recognize that snorkeling makes it easier. That is why I take a snorkel with me when I dive, potentially to save air in my tank but also as a backup for an alternate breathing aid if I am somehow separated from the boat, especially in a high sea state.

I agree with you.