Larger Tanks for deep dives (100ft)
- Thread starter salub2007
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I love having doubles on dives over 100 ft. from boats.
No need to switch tanks, plenty of reserve air. (they like you to have 1/3 out 1/3 return and 1/3 for acent). With doubles you don't lose the left over gas from the first dive. You can also set them up independly for redundancy.
btw I have double 120's which I can seperate as singles.
No need to switch tanks, plenty of reserve air. (they like you to have 1/3 out 1/3 return and 1/3 for acent). With doubles you don't lose the left over gas from the first dive. You can also set them up independly for redundancy.
btw I have double 120's which I can seperate as singles.
So you think they were suggesting they double up a HP100 with an AL80 or they just simply sling an AL80 and plan it as part of their gas plan?
I was assuming since the OP asked about a pony that the 2nd poster was suggesting the AL80 be slug as a pony.
UCFKnightDiver
Contributor
And that is what I thought, hence the reason I was asking him about that.
Hey, if any of you will throw away an AL80 tank, please reserve one for me. I will be in San Diego next May in hotel .....
Ask for Eduardo Moreira. I will receive one of those dam AL80 tanks with pleasure.
Ask for Eduardo Moreira. I will receive one of those dam AL80 tanks with pleasure.
1. You really need to figure out your SAC rate (which your instructor should go over). Once you figure out the SAC rate, you can multiply it by a conversion factor (to account for depth) and find out how much total cubic feet of gas you will consume on that dive. Assuming you are diving on a single tank, you need to multiply that number by 3 for penetration purposes, maybe more depending on how much reserve you want. For your purposes, the pony should not be used UNLESS it is an emergency, it should ONLY be a reserve calculated independently from what you have on your back. You should have enough in the pony to get you safely to the surface.
2. Doubles are not a bad option at all. For recreational purposes though, if you choose doubles, make sure you are only using 1/6 and not 1/3.
3. Deep dives, especially deep wreck dives, require experience and I commend you for getting the training. Take your time...The deep course you are taking is a recreational one, if you plan on 'staging' or doing deeper penetration, get the technical training.
EDIT: Recreational penetration has many many limitations, gas supply is only one of them...
2. Doubles are not a bad option at all. For recreational purposes though, if you choose doubles, make sure you are only using 1/6 and not 1/3.
3. Deep dives, especially deep wreck dives, require experience and I commend you for getting the training. Take your time...The deep course you are taking is a recreational one, if you plan on 'staging' or doing deeper penetration, get the technical training.
EDIT: Recreational penetration has many many limitations, gas supply is only one of them...
adm3745
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Doesn't that give you the exact useable gas as if you were only diving one cylinder.
How did we get into talking about penetration and diving thirds? The OP just said he was going to do some deeper wreck dives -- he didn't say he was doing any penetration. There is generally no need to dive thirds on exterior surveys, unless it is imperative to return to the upline.
As far as a pony bottle size, it isn't dependent on what size tank you use. You're carrying a pony as insurance against a catastrophic gas loss from your primary supply, so the pony bottle needs to have enough gas in it to get you, in a safe and controlled fashion, to the surface from the deepest part of your proposed dive. To calculate this requirement, you need to know what your typical gas consumption rate is, and then make an adjustment for stress (typically doubled). Then you need to look at the ascent profile you would like to do in such a situation.
We use 20 cubic feet per diver as a reserve from 100 feet. If your gas consumption is typically significantly higher than .5 cfm, you might need more.
As far as a pony bottle size, it isn't dependent on what size tank you use. You're carrying a pony as insurance against a catastrophic gas loss from your primary supply, so the pony bottle needs to have enough gas in it to get you, in a safe and controlled fashion, to the surface from the deepest part of your proposed dive. To calculate this requirement, you need to know what your typical gas consumption rate is, and then make an adjustment for stress (typically doubled). Then you need to look at the ascent profile you would like to do in such a situation.
We use 20 cubic feet per diver as a reserve from 100 feet. If your gas consumption is typically significantly higher than .5 cfm, you might need more.
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