PADI tech 50 no refill between dives

[tbone1004]

Nonsense.

When doing my Divemaster in the US some 20 years ago. Dives were "split" in half with one tank in order to increase the number of dives on the logbook.

You only fool yourself with that kind of practice

there are times for both. There is a lot of debate in "number of dives" and "hours underwater" and which one is more important.
You can argue that for something like a tech 50 course that the number of dives is more important than the bottom-time because the course is about managing gas changes which are done on ascents and descents. Once you are at the bottom, you are just diving, so whether it is a bounce dive, or a 3 hour bottom time, the important "skills" are done on the ascent and descent so for that the number of dives are more important.

 

[elmo]

I am not familiar with the PADI tech course structure, but assuming the objective of those dives was to practise ascents, gas switches, holding stops, teamwork and monitoring gas, I think doing two short dives off one double fill is absolutely fine.
The students should have calculated their minimum gas for the 50m and 40m dives beforehand, and be monitoring it so they know when to call the dive.
Of course I'd like to see some longer dives on the course as well.

 

[Miyaru]

That's a 26 minute dive, not a touch and go. On a first dive in a deco class I certainly don't put my divers in actual deco anyway. I want to see them hold simulated stops and deal with gear and emergencies. Most of the drills are on ascent anyway. No reason to mess around at max depth just to build up deco time for no reason other than to build up deco time. At least not on the first dive.

Now if all of the divers were like that, I might have some issues, but dealing with limited resources should be part of the course as well.

-Chris

Let me phrase that differently:
To my opinion, that was a touch-and-go dive.

If this was a course dive, it was one of the last two dives in the Tec Deep range. So no first-deco dive nor simulated stops.
I agree, 10 minutes on the bottom gives you some short stops, which are almost close to a slow ascent.
Anyway, that's up to her instructor. I don't count the number of dives in the course, but the minutes spent under water. And that's a minimum of 720 for the whole course.

 

[tursiops]

Let me phrase that differently:
To my opinion, that was a touch-and-go dive.

If this was a course dive, it was one of the last two dives in the Tec Deep range. So no first-deco dive nor simulated stops.
I agree, 10 minutes on the bottom gives you some short stops, which are almost close to a slow ascent.
Anyway, that's up to her instructor. I don't count the number of dives in the course, but the minutes spent under water. And that's a minimum of 720 for the whole course.

Yes, if she went to 50m and then to 40m, it must have been dives 3 and 4 of the course, because those depths are beyond the standard for dives 1 (10m) and 2 (24m). The standard for Dive 3 (30 to 50m) is a real deco dive with two gas switches. Dive 4 (40-50m) is also a real deco dkive, with two gas switches.

 

[boulderjohn]

I don't count the number of dives in the course, but the minutes spent under water. And that's a minimum of 720 for the whole course.

In case anyone was as startled as I was...

I contacted Miyaru, and he assured me that the 720 minutes is his personal standard, not PADI's. (I was searching frantically through the standards.) Additionally, when he says 720 minutes "for the whole course," he is talking about Tec 40/45/50, not just Tec 50.

Just to make sure everyone is clear, the two dives being mentioned have to be the last two dives of the course, not the first two. The first of those two dives must be between 100-165 feet, and the second has to be between 130-165 feet. They each have to be decompression dives using two deco gases, but there is no mention in the standards of a required bottom time.

 

[DevonDiver]

Reeks of low quality.

Essentially a bounce dive. 26 minutes RT, less 5 mins ascent time and 10 mins BT... gives barely any staged deco...just a slow crawl to the surface.

There's no educational reason for this... it's just instructor cheapskating and gross under-training...ticking a box so that a c-card can be dished out.

If I saw these dives in a logbook as "qualifying" dives for Tec50, I'd not consider the diver suitably experienced for extended range diving.

 

[elmo]

Just to make sure everyone is clear, the two dives being mentioned have to be the last two dives of the course, not the first two.

Thanks for the clarification. With that being the case, I take back my comment that the short dives are fine on the basis that their purpose is to practise ascents, gas switches, etc. By the end of the course you want to be diving real dives similar to what you would be doing post qualification (whatever the standard says). 10min of deco is not what I'd expect from a Tec 50 diver.

 

[tbone1004]

Thanks for the clarification. With that being the case, I take back my comment that the short dives are fine on the basis that their purpose is to practise ascents, gas switches, etc. By the end of the course you want to be diving real dives similar to what you would be doing post qualification (whatever the standard says). 10min of deco is not what I'd expect from a Tec 50 diver.

part of the issues with doing those long dives at the end of class for the instructor is mandatory deco, especially lots of it come with a lot of risk. Much better to hit the depth limit and not incur mandatory deco for the skills to be done at the surface in case anything goes sideways. At a roughly 1:1 ratio of bottom time to deco time at 50m, it's better to not spend that much time at depth and rack the time up on ascent where if something goes wrong, you can make a more direct ascent to the surface

 

[elmo]

part of the issues with doing those long dives at the end of class for the instructor is mandatory deco, especially lots of it come with a lot of risk. Much better to hit the depth limit and not incur mandatory deco for the skills to be done at the surface in case anything goes sideways. At a roughly 1:1 ratio of bottom time to deco time at 50m, it's better to not spend that much time at depth and rack the time up on ascent where if something goes wrong, you can make a more direct ascent to the surface

When is the best time for a student to experience substantial mandatory deco for the first time? First dive after qualification when there is no instructor to supervise and provide support? Much better in my opinion to deal with that towards the end of the course so that if something does go wrong, there is support from the instructor.

 

[tbone1004]

When is the best time for a student to experience substantial mandatory deco for the first time? First dive after qualification when there is no instructor to supervise and provide support? Much better in my opinion to deal with that towards the end of the course so that if something does go wrong, there is support from the instructor.

after progressive penetration, no need to get into substantial deco in class or immediately after. Just because you have done something and are certified to do it doesn't mean you should just hop right in and on your first dive after class go to the extent of that certification.
My general gut says that after you complete a course, you should fall back to the extend of the previous level and work your way up to the limits of the new one.

unfortunately with PADI, the difference in tec45/50 is pretty negligible outside of the second bottle and that isn't actually needed for these dives. In this case it shouldn't actually change anything about your diving, so you go back to the dives you were doing before class and just start taking a second bottle with you.

The better example would be getting full trimix after being a normoxic diver. Just because you are now certified for an unlimited depth vs. 200ft doesn't mean you should just up and go to 500ft right after class, nor should your instructor take you that deep. You now learned about the consequences of deep helium, the need for 2-3+ deco bottles and how to handle them, so you go back to the normoxic range, but start carrying those extra deco gases to start practicing, but doing so in the same environment you are comfortable in. As you gain comfort and experience, those dives gradually get deeper and longer, but you don't go straight to 100m right out of the gate. That's irresponsible and incidentally the reason that agencies like PADI felt the need to make like 8 classes from deco to deep trimix to force you to slow down