max depth with an 80 cuft. tank

[fl-diver]

I think on most every dive operation in south Florida and the Caribbean offers dives in the 80'+ range and you are unlikely going to find anything but alum 80's on board.
Many people with very limited skills do these dives everyday and make it back to the boat alive and healthy.
I switched to steel 100's and 120's a few years ago and I just use them to extend my dive time which is what most people would probably do given bigger tanks.
The solution is simple... leave the bottom with plenty of gas.
Regardless of tank size a blown o-ring at depth (which can be solved by diving DIN) or a first stage failure is highly unlikely.

 

[GrumpyOldGuy]

Alright, I will go buy a Faber 149 and strap on a spare air (hey with redundant air I am invincible). With 152cu ft of gas I am good to go to 150'. When I hit 550PSI, I will reach over and press the elevator button and hit the surface in 10 seconds flat with 500PSI remaining. If I forget to check my air, its OK cause I am diving wet and will feel cold before I run out of gas. The computer flashing red on my wrist makes a nice marker light. When I get to the boat, I can grab my backup out of the bag for my next dive.

[If the sarcasem is not clear - do not do this stupid dive plan]

There is simply no subsitute for doing the math (dive planning / gas planning) when going deep. If math is not your thing, there are spread sheets and charts on SB available. The rules of thumb just don't work at the extremes. Take the time, do the math (I want to say do-it-right, but that would really stir the pot).

 

[AfterDark]

There is simply no substitute for doing the math (dive planning / gas planning) when going deep. If math is not your thing, there are spread sheets and charts on SB available. The rules of thumb just don't work at the extremes. Take the time, do the math (I want to say do-it-right, but that would really stir the pot).

Amen. The way it always has been and should always be. Most dives I know within a few hundred psi how much gas I'll have left at the end of a dive if everything goes according to plan which it mostly does.

 

[David_57]

Roatan shore dive at Fantasy Island 80 cu ft slow decent to 152ft once I hit 152ft a slow accent to 40ft hung around at that depth not sure how long then accent to safety stop for about 5 minutes surfaced with air to spare although I was running the math in my head most of the time.

Would I try this up here in the St Lawrence river not a chance but down south in warm water 3 mil wetsuit great visibility no problem. I thought about it after and wondered what if I started free flowing at 152ft stress goes up SAC increases not so sure if I would make it back to the surface with no ill effects, but hey I guess that's the risk I am willing to take. If I could rent a pony down south for sure that is what I would do until then I will be doing many dives to at least 100ft on a 80 cu ft would I go to 152ft again on a 80 cu ft dunno maybe, :blinking:

 

[Nemrod]

Is an 80 cuft tank enough air to safely go beyond 80'? My answer is yes but not safely. Please share your opinion.

For you, no, for me, yes.

Define "safe" as I don't know of anything that does not have risk attached to it worth doing.

N

 

[MauiScubaSteve]

Here in Hawaii, every week there are literally thousands of vacation divers who go below 80' on 80's, 72's and even 63's (petite females mostly). There are also some guides using 63's for these dives (petite females mostly) although I don't like that practice.

Have you noticed all the deeper than 80' on 80's injury and death news reports coming from Hawaii? Vacationers are begging us to take them on these dives!

 

[GrumpyOldGuy]

For you, no, for me, yes.

Define "safe" as I don't know of anything that does not have risk attached to it worth doing.

N

What, you never heard of safe sex?

 

[Gombessa]

Here in Hawaii, every week there are literally thousands of vacation divers who go below 80' on 80's, 72's and even 63's

Have you noticed all the deeper than 80' on 80's injury and death news reports coming from Hawaii? Vacationers are begging us to take them on these dives!

Coincidentally, I was thinking about HI as I read this thread! Specifically, I've been to the Corsair on Oahu maybe four times total with 2 or 3 different dive ops over the last two years. On two of these 4 times, a vacation diver in my group has gone OOA on the way up the line and was breathing off the DM's octo for the duration of the safety stop. Seemed routine both times, the OOA divers carries on as usual during the SI and did the second dives as planned.

The wife of one of these same divers (they were both certified the week before on Maui) told me how she mistook her inflator for the deflator button and made a buoyant ascent from 90ft on an earlier dive that week (she was told to skip the second dive of the day).

Safe? Reserving judgment, but from what I've seen, what I may consider unsafe more often results in nothing happening, or rescues that the victim doesn't realize is anything serious, so I try not to equate a lack of injury-and-death-news with a practice (or individual diver) being safe.

Just my $0.02.

 

[dktexas54]

This discussion sounds familiar...oh yeah! the old debate during the 70's can a diver get bent on a 72 cu ft tank? Boring..

Well! boring huh! Why don't you give a take on something not boring!

 

[Doc Harry]

An AL80 doesn't give you a lot of time down deep, especially once you subtract out your rock-bottom gas. It's okay for drift diving below 80 feet. It's also okay for boat diving in areas where there isn't a current.

If you are diving deep in an area where there is a stiff current, and you need to ascend and descend along the mooring line, an AL80 will give you only 5-8 minutes to explore away from the mooring line (depending on your SAC). This is where the limitations of the AL80 are really noticable.