cranstonjdc
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Im new to diving. have logged 15 dives. I was just curious how big of a difference 100s make compared to 80s.
Tank size question from a beginner diver.
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For? Length of dive? Buoyancy characteristics??
100's have 20 more cubic feet (25% more) of gas.
100's have 20 more cubic feet (25% more) of gas.
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cranstonjdc
Registered
Thanks. and I was asking about length of dive
Bubbletrubble
Contributor
It entirely depends on the depth profile and your gas consumption rate.
RonFrank
Contributor
The two biggest variables in air consumption are the depth of the dive, and the divers SAC rate. SAC rate can be impacted by the divers size and lung capacity as well as experience. Most divers can stretch an AL80 and reach NDL without running out of air. Newbies maybe not so much.
Steel tanks have different buoyancy characteristics vs. Alum. Most Alum tanks are 2~3 lbs negative full, and a few lbs positive empty. Steel tanks tend to be more negative full, and a couple lbs negative empty.
AL 100's are larger and heavier than AL80's. However the biggest difference is that the diameter is a bit larger, and that is a PITA since one has to adjust CAM bands. Steel 100's are the same diameter as AL80's, and a bit shorter.
Steel tanks are a lot more expensive vs. AL.
As a new diver I would hold off on tanks until you have a few more dives, however Steel 100's are very nice, so if you want to blow a few hundred bucks you would likely not regret buying steel. AL 80's are cheap used if you can find a good deal, under $100 for one in hydro and vis.
Steel tanks have different buoyancy characteristics vs. Alum. Most Alum tanks are 2~3 lbs negative full, and a few lbs positive empty. Steel tanks tend to be more negative full, and a couple lbs negative empty.
AL 100's are larger and heavier than AL80's. However the biggest difference is that the diameter is a bit larger, and that is a PITA since one has to adjust CAM bands. Steel 100's are the same diameter as AL80's, and a bit shorter.
Steel tanks are a lot more expensive vs. AL.
As a new diver I would hold off on tanks until you have a few more dives, however Steel 100's are very nice, so if you want to blow a few hundred bucks you would likely not regret buying steel. AL 80's are cheap used if you can find a good deal, under $100 for one in hydro and vis.
JohnAC
Contributor
Hi Cranstonjdc, for me it has been a BIG difference.
Like you I started using AL 80's and was getting 35-45 minutes per dive. Now I'm just OW certified, so Im staying above 60fsw.
3 months ago I acquired a PST steel hp 100. I took more than 6 lbs of lead off and can easily dive an hour with gas to spare.
As a rule steel tanks last years longer than Al 80's, have better buoyancy characteristics and are shorter than Al 80. Yes they cost more, but they are worth every penny IMHO.
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Clammy
Contributor
Al80s can last a LONG LONG LONG LONG LONG time. Steel tanks will probably have rust issues and need to get tumbled until it can't be over time. But then AL tanks can get screwed up too.
That still doesn't outweigh the benefits of steel tanks over AL80s in cold water IMO.
That still doesn't outweigh the benefits of steel tanks over AL80s in cold water IMO.
In a way, tanks don't die, they are MURDERED. Usually, a tank will fail from abuse, like over-filling or bad fills (wet) rather than age. Aluminum tanks handle wet fills better than steel ones. If properly cared for, either modern steel or aluminum tanks can last centuries. I use several tanks that were made in 1923 (yes, over 90 years old).
As mentioned before, steel tanks usually have better buoyancy characteristics than aluminum tanks and especially HP steel tanks are usually smaller and effectivly lighter than other tanks of the same capacity.
As mentioned before, steel tanks usually have better buoyancy characteristics than aluminum tanks and especially HP steel tanks are usually smaller and effectivly lighter than other tanks of the same capacity.
How about the ones I have from 53 and 55. The other issue is that some places will not fill al tanks older than 1990 and at least 2 local hydro facilities don't even want to touch al older than 15 years from original born on date. Steel tanks do not have to have rust issues. If one uses good air, does not let them run dry, and gets a good hydro place that knows what they are doing and is careful even flash rust can be non issue. Tumbling does not significantly affect a steel tank unless you use too harsh of a medium or the tank has not been taken care of in the first place. For minor inside rust a whip will work just as good and be less abrasive on the metal. I would never select al tanks as my primary air source if I could avoid it. Steels, especially low pressure ones, are more cost effective in the long run.
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