max depth with an 80 cuft. tank

[dumpsterDiver]

I used to do spearfishing dives to around 180 ft pretty often with an 80 and a 13 pony bottle. We would do maybe 4 dives per day and try to stay out of deco, or only get like 4 -5 minutes deco. Often we breathed oxygen on the safety stop (just to be safe and everything)

I think we would get about 9 minutes to hunt on the bottom before the deco light comes on. I found that I had TOO MUCH air on these dives and tended to get CO2 headaches. After a while I realized it was better for me to breath harder and deeper than I felt I needed even on the descent because it prevented the headaches and I had no use for extra air in the bottle at the end of the dive. The headaches probably arose from periods during the dive when I stopped breathing and tried to stalk fish without bubbles. These were always solo dives which means I didn't have to save air for a buddy. An 80 is enough air for a no deco dive to depths past 80 feet, but I won't do it without a pony bottle for bail out.

 

[AfterDark]

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

I'm concerned that may violate the TOS.
Come on! 80's have been dived for decades now, heck I remember when it was considered a BIG tank and 72's @ 2250PSI was the norm. I just sent my last 72 to hydro this week. I'll live on the edge and dive with it!. This thread is just internet masturbation.

 

[Luku]

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!

So true, just today the group on our boat went to 95' to check out some Tinkers. 80+ on 80's is common place here.

 

[Superlyte27]

What, you never heard of safe sex?

That term makes me laugh. It's absolutely one of my favorite oxymorons. There is no such thing.

 

[halocline]

Every day for the last few decades hundreds of divers have been exceeding 80 ft on AL80s in Cozumel alone. Multiply that by dozens of other caribbean dive spots and I think you have an answer to the somewhat silly question "can you safely exceed 80 ft on an AL80."

And that's just in the caribbean. Consider SE Asia, other tourist diver locals that use AL80s.....

 

[UCFKnightDiver]

Do your rock bottom math, you can use an 80 but you sure don't get a whole lot of gas to use, or that you should use.

Assuming both divers have a sac rate of 1 cu ft and are diving at 100 ft where one diver has a catastrophic loss of gas.

- You would need 8 cuft at 100 ft assuming 1 minute to resolve a situation
- 10 cu ft from 100-50 ft assuming an ascent rate of 30 ft per minute which is 1.66 minutes needed. (If just doing a 3min saftey stop then you would need 15 cuft here)
- Assuming minimum deco from here you need 17.57 cu ft and a ascent to the surface totaling 5 minutes (If doing just a 3minute saftey stop then you would need 8.7 cu ft for this part, and more for the previous part)


This means you need 1420 psi in a AL80 to reach the surface in the event of a catastrophic gas failure of your buddys gas. So your turn pressure probably needs to be 1600-1700 because I don't think you can breath your tank down to 0.

I hope I did my math correctly, but I'm sure someone will point it out if I didn't.

 

[AfterDark]

Do your rock bottom math, you can use an 80 but you sure don't get a whole lot of gas to use, or that you should use.

Ya get 80 cu ft.

 

[Mike Boswell]

I used to do spearfishing dives to around 180 ft pretty often with an 80 and a 13 pony bottle. We would do maybe 4 dives per day and try to stay out of deco, or only get like 4 -5 minutes deco. Often we breathed oxygen on the safety stop (just to be safe and everything)

I think we would get about 9 minutes to hunt on the bottom before the deco light comes on. I found that I had TOO MUCH air on these dives and tended to get CO2 headaches. After a while I realized it was better for me to breath harder and deeper than I felt I needed even on the descent because it prevented the headaches and I had no use for extra air in the bottle at the end of the dive. The headaches probably arose from periods during the dive when I stopped breathing and tried to stalk fish without bubbles. These were always solo dives which means I didn't have to save air for a buddy. An 80 is enough air for a no deco dive to depths past 80 feet, but I won't do it without a pony bottle for bail out.

Reading your post made me laugh and brought back memories.... It was a different world and we were different people.

But I'm not like that no more...

 

[gcbryan]

I guess the question should have been "Given you and your buddy's SAC rate how deep do you feel it is prudent to go on an aluminum 80 and why (explain your reasoning)?".

 

[UCFKnightDiver]

Ya get 80 cu ft.

No you don't.... I edited my previous post. Look up ^.