STEELS for stages?

[Mark Chase]

Originally Posted by ianfirmin

I've got a steel faber with clips and a reg, currently with 230 bar of air. It's total weight is 12.7kg and 3.75kg neg on my fishing scales when it's in the bath.

By my calcs 230 bar in 7 litres weighs about 1.9kg. What am I doing wrong? Thus it should be about 1.8 neg when empty. What am I doing wrong?

Ill do a demo and take pics tomorow and show you how my lightweight Faber steel 7s are.

ATB


Mark

[Brian of Aquanauts]

Originally Posted by Mark Chase

Ill do a demo and take pics tomorow and show you how my lightweight Faber steel 7s are.

ATB


Mark

Don't forget, you can't prove that your steels float, if they're resting on your hand, the bottom, your bottom or clipped off to a trapeze, your d-ring or a passing trout. They float if they're on the surface, otherwise they sink.

No one is arguing that steel stages don't trim out behind your arm. Some us think they're just too heavy to wear.

[ianfirmin]

I know this subject has been covered before but it's got me thinking (dangerous?). Now, any gas you carry is useless unless you can hold your shallowest stop with an empty tank. So, you need to be able to breathe your last bottle down to nothing at, say, 3m.

Let's say you weight yourself so that you can breathe a 3l of O2 down to nothing at 3m. What about the another bottle(s) that you need to get yourself to 3m. If they are buoyant when empty you can dump them when empty and effectively give yourself extra weight. If they are negative you have to continue to carry them. Due to my neoprene DS I can stay at 6m with less weight needed than at 3m. Soooo, if I had a buoyant bottle at 6m I could dump it and still be weighted OK to breathe the O2 down at 3m.

Soooo, the optimum (I havn't tried the maths yet) would be to have multiple bailout/stage tanks that you can dump when empty (as long as they are buoyant when empty).

Not explained very well I know.

[Mark Chase]

Originally Posted by ianfirmin

I know this subject has been covered before but it's got me thinking (dangerous?). Now, any gas you carry is useless unless you can hold your shallowest stop with an empty tank. So, you need to be able to breathe your last bottle down to nothing at, say, 3m.

Let's say you weight yourself so that you can breathe a 3l of O2 down to nothing at 3m. What about the another bottle(s) that you need to get yourself to 3m. If they are buoyant when empty you can dump them when empty and effectively give yourself extra weight. If they are negative you have to continue to carry them. Due to my neoprene DS I can stay at 6m with less weight needed than at 3m. Soooo, if I had a buoyant bottle at 6m I could dump it and still be weighted OK to breathe the O2 down at 3m.

Soooo, the optimum (I havn't tried the maths yet) would be to have multiple bailout/stage tanks that you can dump when empty (as long as they are buoyant when empty).

Not explained very well I know.

I think you did OK

When I dived OC i used steel 7s and steel 10s. I had no issues i with them. i just compensated with my wing when they were full. When they were empty (which they were after most dives) they were a bit floaty but not enough to cause a problem. Again just trim out with a wing.

Problem came with Ali's a bit lighter full but much more floaty empty? How do you compensate for this? You cant so you need to carry more lead thus loosing the advantage of the lighter tanks.

When I switched to CCR I started to use trimix in the deep bailout. This floats a steel 10. Mean while, the steel 10 with the 50% in is still neg. As a result I was off balance so I decided to try Ali 80s. They were nice but an an 80 with 50% in still sinks. It 1.5Kg neg full without a regulator on it. Down side is empty they float like bugger. With two empty (less than 50 bar) 80s I was struggling.

End result is I went for an 80 of Nitrox 50 and a steel 10 of Trimix. I could handle one empty 80 and the steel was no problem empty. The 80 full is still heavier than the steel 10 with 18/45 in but its better than a steel.

ATB

Mark

[Mark Chase]

Originally Posted by Brian of Aquanauts

Don't forget, you can't prove that your steels float, if they're resting on your hand, the bottom, your bottom or clipped off to a trapeze, your d-ring or a passing trout. They float if they're on the surface, otherwise they sink.

No one is arguing that steel stages don't trim out behind your arm. Some us think they're just too heavy to wear.

I just find "too heavy" easier to deal with than too floaty?? I have dived with three 10ltr steels and had no issues at all. If I had three 80s Id strugle when they were empty or Id have to send them up the line.

The 10s are much easier to handle on the boat and lighter when dry and once in the water i just trim out the extra weight with my wing.


When they are empty they are not too flaoty so they dont cause me any greif.

Whats the problem?


I have tried both and i just dont understand why people think Alis are so great. I can only asume they dont empty them very often on a dive.

Id do, so perhaps i am more sensitive to the problems with ali tanks.

ATB

Mark

[ianfirmin]

Originally Posted by Mark Chase

When I switched to CCR I started to use trimix in the deep bailout. This floats a steel 10. Mean while, the steel 10 with the 50% in is still neg. As a result I was off balance so I decided to try Ali 80s. They were nice but an an 80 with 50% in still sinks. It 1.5Kg neg full without a regulator on it. Down side is empty they float like bugger. With two empty (less than 50 bar) 80s I was struggling.

This is the point I'm getting to. I can't quote you exactly but I'm sure you have said something along the lines of "in 450 hours of ccr diving I have never had to use a bailout in anger". If that's the case, why not use a bottle that's positively buoyant when empty? During a normal dive you have less gas in your wing and all the advantages that entails (less drag, smaller buoyancy change with depth etc). If you actually HAVE to use this bail out cylinder you breath it down and then dump it (clip it to a blob line if you want to find it again).

You don't need the extra weight to keep down at shallower depths and you run less gas in your wing during a normal dive. Probably applies only to ccr though. I can understand that using floaty when empty tanks for stages on OC and having to dump them could become a real pain but on ccr it should happen only rarely. In your case only during drills??

Cheers
Ian

[nigelH]

Originally Posted by ardhill

Just a pity it not sea water, but I can guesstimate the difference... Or Nigel, you could tell us exactly how to work it out

ARGH!!!
BANGS HEAD!!!

If we have weight in dry and wet we know the volume exactly so we can predict seawater spot on the nail.

Archimedes, a mathematician in Syracuse at about 215 BC, was reputedly given the job of deciding if a crown was made from the gold supplied or if there was some other metal in the core so the makers increased the profits. His trick was to weigh it both dry and in water and postulated his law that we now render as 'the upthrust equals the displacement'.

Unfortunately for the crown makers it, allegedly, didn't come out as pure gold and in those days when they said 'heads will roll' they meant it.

[Mark Chase]

Originally Posted by ianfirmin

This is the point I'm getting to. I can't quote you exactly but I'm sure you have said something along the lines of "in 450 hours of ccr diving I have never had to use a bailout in anger". If that's the case, why not use a bottle that's positively buoyant when empty?

Because the day I do have to bailout I dont want to have to strugle with two boyent tanks. The steel floats full anyway so why use an ali?

Steel floats arse up with 250bar in. Ali is neg 1.5KG with 230bar of 50 In fresh water%

During a normal dive you have less gas in your wing and all the advantages that entails (less drag, smaller buoyancy change with depth etc). If you actually HAVE to use this bail out cylinder you breath it down and then dump it (clip it to a blob line if you want to find it again).

The steel floats and the 50% is in an ali 80 so I cant do much better than that can I?


Old pic of my inspo days but Ali 80 on the left (of pic) steel 10 on the right.

You don't need the extra weight to keep down at shallower depths and you run less gas in your wing during a normal dive. Probably applies only to ccr though. I can understand that using floaty when empty tanks for stages on OC and having to dump them could become a real pain but on ccr it should happen only rarely. In your case only during drills??

Cheers
Ian

Yes, thats why when I dived OC i used steel cylinders exclusivly




ATB

Mark

[ianfirmin]

Originally Posted by Mark Chase

Because the day I do have to bailout I dont want to have to strugle with two boyent tanks. The steel floats full anyway so why use an ali?

Steel floats arse up with 250bar in. Ali is neg 1.5KG with 230bar of 50 In fresh water%

What's the size of the steel in the picture? And, are there regs on it?
Cheers
Ian

[warmwaterdiver]

the steel thats "floating" Mark, I can see its arse light/neck heavy, but is it floating or is it just arse light with the neck sitting on the bottom? & including regs?

what kind of 50% fills were you putting in the ali80, 160 dir bar, or 300 chasey bar?