100 size tanks?

[brsnow]

It's not as common in the south, but it does happen -- not recently to me, but in 2019 we did have some current conditions in the south that caused us to change dive sites (don't recall which sites we were trying to go to before we changed).

There are certainly times very south you don’t have clarity for certain dives, but plenty of common sites to get a deep first dive. I was just curious as I hadn’t really seen the bigger tanks before. Sounds like new divers or those with cameras benefit.

 

[Bob DBF]

There are certainly times very south you don’t have clarity for certain dives, but plenty of common sites to get a deep first dive. I was just curious as I hadn’t really seen the bigger tanks before. Sounds like new divers or those with cameras benefit.

For a timed guided dive, I can see your point. If one is planning and executing their own dives, on their own schedule, more gas may be needed to complete the dive objectives.

 

[brsnow]

For a timed guided dive, I can see your point. If one is planning and executing their own dives, on their own schedule, more gas may be needed to complete the dive objectives.

I am getting this seems like a sensitive subject, but on most old school dive ops in Cozumel you don’t see bigger tanks and they are not planned dives at all. I think I have figured out who needs the bigger tanks. Appreciate the responses, I understand.

 

[rob.mwpropane]

Most divers do devils throat and others with 80. The locals do some incredible dives on 80.

And that's the beauty of diving, everyone can dive however they want. I'm not saying it's wrong, just not what I would do.

Last weekend I dove in pitch black water that was 38F. I would feel really uneasy with an 80. Heck I'd feel uneasy with just a single tank on.

On paper (talking about buoyancy characteristics) a steel HP 100 makes so much more sense than an 80 though. And no one ever came up from a dive saying they wish that had less gas in their tank

Full disclosure though; I don't have a lot of experience diving warm clear water. Maybe I would feel different.

 

[lexvil]

With planing you can do a lot with an 80

12 minutes on the San Francisco Maru. Would I prefer a 100, heck yea but …

 

[RyanT]

I think I have figured out who needs the bigger tanks. Appreciate the responses, I understand.

I'm one. I dive with double LP85s that are overfilled, so that I have about 200 cf on my back. I sling a 40 cf bottle under my left arm. Sometimes if I think I'll be a little deeper, I go ahead and sling a second 40 cf under my arm. That's 240-280 cf, and about the right amount of gas.

 

[rob.mwpropane]

I'm one. I dive with double LP85s that are overfilled, so that I have about 200 cf on my back. I sling a 40 cf bottle under my left arm. Sometimes if I think I'll be a little deeper, I go ahead and sling a second 40 cf under my arm. That's 240-280 cf, and about the right amount of gas.

Sounds about right!

 

[drrich2]

80’s target the mainstream, but think of it like a normal distribution bell-shaped curve - there are outliers.

People vary in size, body form, obesity, sex, gender and cardiovascular fitness, experience/skill/comfort level diving, and a range of other things, and our bodies are designed for a topside environment where air is not a scarce resource.

While the stereotypes don’t hold with everyone, big men, those of us unlikely to be recognized at the gym, new divers and some others are often ‘air hogs.’

And an 80 is not really enough.

In other news, the common 100-cf AL tank has a rated fill pressure of 3300 PSI not 3000, so the tanks often hold around 90-cf (because they’re often filled to 3000).

 

[scubadada]

80’s target the mainstream, but think of it like a normal distribution bell-shaped curve - there are outliers.

People vary in size, body form, obesity, sex, gender and cardiovascular fitness, experience/skill/comfort level diving, and a range of other things, and our bodies are designed for a topside environment where air is not a scarce resource.

While the stereotypes don’t hold with everyone, big men, those of us unlikely to be recognized at the gym, new divers and some others are often ‘air hogs.’

And an 80 is not really enough.

In other news, the common 100-cf AL tank has a rated fill pressure of 3300 PSI not 3000, so the tanks often hold around 90-cf (because they’re often filled to 3000).

@drrich2 is absolutely correct. Gas consumption is highly variable and is, approximately, a normal distribution, see Average Gas Consumption

 

[scrane]

I have been diving a long time and my air consumption is pretty good. Last year I went to Roatan with a friend who is a new diver. He had a lot of concern about his not so great SAC. I was happy to arrange for him to get a larger tank to reduce his anxiety and help him relax and enjoy his dives. Not a big deal.