Tank Boots, Boats and DIR

[jonnythan]

Interesting ... out here virtually every DIR diver dives double PST 104's.

This is the first I've heard that they don't balance out well ... for the past four years, all I've been hearing ... and from several GUE instructors at that ... is that the reason DIR divers choose 104's is because of their superb balance characteristics.

I wonder if this isn't another one of those east-coast DIR vs west-coast DIR issues ...

... Bob (Grateful Diver)

That's cause it's not true, Bob.

Steel tanks are perfectly fine for diving. Tank boots suck and eat tanks. There's no reason to have them. Boats have proper protection already. There's no reason for each tank to have its own.

 

[MXGratefulDiver]

That's cause it's not true, Bob.

Steel tanks are perfectly fine for diving. Tank boots suck and eat tanks. There's no reason to have them. Boats have proper protection already. There's no reason for each tank to have its own.

I wouldn't be quick to say it's not true ... apparently he's quoting Bob Sherwood, andI think it's safe to assume there's some reasoning behind it ... it's just that we haven't been given that reasoning on this coast, and it's not consistent with my own (limited) experience. I know a couple of folks who use AL80's ... but the vast majority around here use PST LP104's or E8-130's. I, personally, use E8-119's ... and although it took me a while to figure out how to use them properly, they seem to balance out quite nicely.

Tank boots have their place ... which is on singles. And in my experience, they don't eat your tank any more than a pair of Highland bands will ... and for the same reasons.

... Bob (Grateful Diver)

 

[RTodd]

GI once said the reason for the no boots rule was that he was seeing too many Florida cave divers standing their tanks up on the picnic benches, where they risked falling over. I got tired of having my steel doubles slipping, falling and shifting while trying to put them on while sitting on the gunnel of a boat. I put the boots back on. I guess that makes me a stroke, but I don't really care.

Yeah right. Tank boots are like valve covers. You don't need them in the water so you don't take them.

Derek's post from Bob covered all of the other stuff really well but everyone seems to be missing the important thing Bob said which is that people latch on to generalizations and only hear what they want to hear. While some of the newer steel tanks work with drysuits als are a better choice for most open water dives. Balanced rig in a steel tank with much greater amounts of gas (weight)/ drysuit context here has more to do with the start of the dive and the ability to get neutral with a bouyancy loss than at the end of a dive.

 

[TSandM]

It's really interesting to read what Bob Sherwood said, because that's what JJ's book says, and when I quoted it some time ago, I was immediately corrected as having misread what was said.

 

[do it easy]

Derek's post from Bob covered all of the other stuff really well but everyone seems to be missing the important thing Bob said which is that people latch on to generalizations and only hear what they want to hear.

I'm still latching onto the things I want to hear. In Bob's message, he stated that AL80s were the tank standard. He did mention exceptions to rules, so I'm assuming this is not a hard and fast rule, so here's my question:

If I trim out better in AL100s and the rest of the team is diving AL80s, which aspect do we compromise- ease of gas planning by diving the same tanks, or trim and buoyancy by diving different tanks?

 

[MXGratefulDiver]

Originally Posted by MaxBottomtime
GI once said the reason for the no boots rule was that he was seeing too many Florida cave divers standing their tanks up on the picnic benches, where they risked falling over. I got tired of having my steel doubles slipping, falling and shifting while trying to put them on while sitting on the gunnel of a boat. I put the boots back on. I guess that makes me a stroke, but I don't really care.

Yeah right. Tank boots are like valve covers. You don't need them in the water so you don't take them.

Derek's post from Bob covered all of the other stuff really well but everyone seems to be missing the important thing Bob said which is that people latch on to generalizations and only hear what they want to hear. While some of the newer steel tanks work with drysuits als are a better choice for most open water dives. Balanced rig in a steel tank with much greater amounts of gas (weight)/ drysuit context here has more to do with the start of the dive and the ability to get neutral with a bouyancy loss than at the end of a dive.

There seems to be two messages in this thread ... one having to do with tank boots, the other with using AL80s as your doubles cylinder of choice.

Seems to me that if you're using AL80's, GI's observation - quoted above - is moot ... you can stand up a set of AL80's just as well without tank boots as you can with them.

With respect to RTodd's comment - I understand the logic ... just not sure I agree with it. It would be interesting to know what cylinders the DIR divers reading this thread are using ... and why they chose them ...

... Bob (Grateful Diver)

 

[Soggy]

It would be interesting to know what cylinders the DIR divers reading this thread are using ... and why they chose them ...

Personally, I use E8-130s. They are only 2 lbs negative each, I don't need to carry a 14lb v-weight, and the extra weight I'm carrying can be ditched through the 2nd stage purge valve if it needs to be or breathed if I need it. Plus, I can get in two long recreational dives and two short technical dives in the 150' range and still have oodles and oodles of gas reserves. I dive almost exclusively in salt water with thick undergarments where I am *absolutely not* overweighted.

Some of the arguments for Al80s include:

• cheaper...true, but you need multiple sets to do a single day of diving, thus you are back to spending more money than on a single set of 130s. That, combined with the fact that they are much less durable and have to be replaced more often makes this point completely null and void.
• easier to dive...I don't know, I never had trouble with my 130s
• lighter...true, but I'm a skrawny chickenlegged guy and I can get myself up a boat ladder in 130s with a deco bottle on in rough seas. Also, at the expense of "lighter" you get less gas. If you want to carry more gas, the "solution" is to carry an al80 stage. Now we are back to the same amount of weight, still less gas, and you are a lot less stable both on the pitching boat and in the water. The argument here is, that you can hand the stage up, but good luck handing up an al80 to the boat when the seas are rough.
• better buoyancy characteristics...that's pretty arguable. Considering the amount of useless lead you have to carry in cold water with a drysuit, I'd say that al80s have horrible buoyancy characteristics for anything but water water 3mm diving or stages.

The post that Derek quoted above was from a long thread on NEUE.com where that was the final answer. The thread is actually quite long and contains a lot of discussion about the relative merits of steel vs aluminum. Most of those guys are doing a lot of freshwater dives, so perhaps the buoyancy issue comes into play more.

 

[detroit diver]

..............
EDIT - Didn't realize this was the DIR forum, having never seen a DIR team in AL tanks let me ask this. Wasn't one of the selling points that you use the same gear for all your dives?

No. That's an over-generalization.

 

[StSomewhere]

It's really interesting to read what Bob Sherwood said, because that's what JJ's book says, and when I quoted it some time ago, I was immediately corrected as having misread what was said.

Well based on your post, I went back this morning to my copy of "Doing It Right: The Fundamentals of Better Diving" and reread the pages on cylinders and I didn't see anything that said only the only acceptable doubles for OW diving were AL80s, except for the caveat about diving doubles in wetsuit. :06:

Now before someone can say "balanced rig", that concept is touched on though its not thoroughly explained. But (and this was pointed out to me elsewhere) what is the reasoning behind doubled AL80s if you are just going to dive them with a 5 lb steel plate or an 8 lb v-weight (or both)?

What am I missing?

 

[CD_in_Chitown]

But (and this was pointed out to me elsewhere) what is the reasoning behind doubled AL80s if you are just going to dive them with a 5 lb steel plate or an 8 lb v-weight (or both)?

What am I missing?

I'm not sure I follow your question, it looks like Bob Sherwood's answer on the reasoning was provided in this thread.