Need Math Lesson

**Dave Sutton** · 3rd July 2007, 20:00

Quote: (Originally Posted by Stephane)

Pssttttttt, Dave, you really need to buy a simple $5 calculator: 2x200=400 not 4000.

Yeah, I'm a dumb shit.

In any case, he's trying to figure out what size "US" tank (IE 13 cubic foot or 15 cubic foot or 6 cubic foot) will fit into the chassis, and wants to compare them to 1.0, 1.5, 2.0 litre bottles for *physical size*, and the point is that there's no way to compare other than to back-convert the US bottles to litres of water volume and then compare.

I'll edit the post with the bad math in it so that future readers aren't challenged by my lack of decimal place awareness...

Dave

**Dave Sutton** · 3rd July 2007, 20:01

Quote: (Originally Posted by Mossyback)

Now all I have to do is find a source for a couple of bottles for my IDA-71 that will come close to fitting inside.
Hank

I use Faber 2 litre steels and let the valves stick thru the bottom....

If you can find 1.5 litre bottles you can keep the regs internal.

I'll buy all the galvanized steel 72's ya'll can send me. I prefer the 1980's vintage PST (Pressed Steel Tank) manufactured ones, not that I'm choosy!

Dave

Mossyback · 3rd July 2007, 21:11

Quote: (Originally Posted by Dave Sutton)

I use Faber 2 litre steels and let the valves stick thru the bottom....

If you can find 1.5 litre bottles you can keep the regs internal.

I'll buy all the galvanized steel 72's ya'll can send me. I prefer the 1980's vintage PST (Pressed Steel Tank) manufactured ones, not that I'm choosy!

Dave

O.K., now I know what to go after.

As for the 72's, my local dive store owner was complaining last week because people kept dropping 72's off at her door after closing. At that time there were approximately 8 or 10 just sitting there. She didn't know how she was going to get rid of them. If you want me to tell her I'll take them if more show up I will, provided you'll take them from me. My wife gets upset when I drag home old diving equipment.

Hank

Rebreatherlab · 3rd July 2007, 21:27

Hey Mossback,

here is what I did to my IDA-71: I scrapped the left scrubber and plugged the holes in the CL, centered up the scrubber/tank retainers and re-riveted them, scrapped all plumbing, got a pair of alu 19 cu.fts (hrm. 2.7L WC 'ish) tanks from catalina, cut holes from the top of the alu box to let valves and regs protrude upwards to help offset the crappy trim.

Now by doing this you will have to give away a bit of CL volume, but at least for me, (small bugger), that gave me just about what I need. further more i put the remaining CL is a sort of bungee web to help offest the inhalation effort. The draw back is that it also affect cracking of the OPV so you need to play with the tension to get right.

If you need more CL volume you could put them inverted and let the handwheels stick out on the lower sides and put some bricks on top, but this ads weight to the assembly. I had trouble as it was really negative with out extra ballast, but then again I am in a 5 mil WS and am also a skinny bastard. The 13 cu.ft's (1.8L WC 'ish) are not really worth the hassle unless you are swapping just to use DIN valves.

You should see my IDA btw. It has more MOD holes in it than aluminium. Sort of a Russian Swiss cheese.

Andy

Quote: (Originally Posted by Mossyback)

Dave, I agree with you, when it comes to imperial stuff things really get out of hand. It's even worse when you live out in the country and your neighbours still talk in rods and acres.

Thanks for the explanation. The local dive shop would like me to junk my old 72's and replace them with 80 cu ft aluminiums. After hearing from all of you, I think I'll just keep using them.

By the way, Dave, do I have to write the test and will it count towards graduation?

Thanks for the sources, Yankee Rebel. I'll get lots of use out of them.

AB - your conversion examples make sense.

Now all I have to do is find a source for a couple of bottles for my IDA-71 that will come close to fitting inside.

Hank

undrh2o · 3rd July 2007, 22:00

Quote: (Originally Posted by Rebreatherlab)

Hey Mossback,

here is what I did to my IDA-71: I scrapped the left scrubber and plugged the holes in the CL, centered up the scrubber/tank retainers and re-riveted them, scrapped all plumbing, got a pair of alu 19 cu.fts (hrm. 2.7L WC 'ish) tanks from catalina, cut holes from the top of the alu box to let valves and regs protrude upwards to help offset the crappy trim.

Now by doing this you will have to give away a bit of CL volume, but at least for me, (small bugger), that gave me just about what I need. further more i put the remaining CL is a sort of bungee web to help offest the inhalation effort. The draw back is that it also affect cracking of the OPV so you need to play with the tension to get right.

If you need more CL volume you could put them inverted and let the handwheels stick out on the lower sides and put some bricks on top, but this ads weight to the assembly. I had trouble as it was really negative with out extra ballast, but then again I am in a 5 mil WS and am also a skinny bastard. The 13 cu.ft's (1.8L WC 'ish) are not really worth the hassle unless you are swapping just to use DIN valves.

You should see my IDA btw. It has more MOD holes in it than aluminium. Sort of a Russian Swiss cheese.

Andy

Can you post pictures? I'm curious because I've been waffling between 13 and 19 cuft tanks for my conversion as I'm worried about the valves/regs protruding below the case (I'll probably need the CL volume as I'm a big bugger)

I like the idea of using valve protectors as a stand but I haven't been able source some cheaply

Rebreatherlab · 3rd July 2007, 22:40

Quote: (Originally Posted by undrh2o)

Can you post pictures? I'm curious because I've been waffling between 13 and 19 cuft tanks for my conversion as I'm worried about the valves/regs protruding below the case (I'll probably need the CL volume as I'm a big bugger)

I like the idea of using valve protectors as a stand but I haven't been able source some cheaply

Sorry, my IDA-71 has retired permanently to the scrap bin since the last 3 years or so. If you really want the valves down I would suggest you try to use some similar valves as used on the inspiration. I mean valves which has the DIN on the same axis as the hand wheel. this will make better space for the 1st stage. If you use standard Thermo valves you might not be able to close the lid depending on what 1st stages you use.

I might have some old pictures some where. I will have a look and post if I find anything of interest.

I know a lot of big buggers who dont take so big breaths. You could easily test by gradually blocking the CL bit by bit. If you can get away with a bit restricted CL I feel this is the best way as the trim is very poor anyway.

Andy

Rebreatherlab · 3rd July 2007, 22:43

Quote: (Originally Posted by undrh2o)

Can you post pictures? I'm curious because I've been waffling between 13 and 19 cuft tanks for my conversion as I'm worried about the valves/regs protruding below the case (I'll probably need the CL volume as I'm a big bugger)

I like the idea of using valve protectors as a stand but I haven't been able source some cheaply

Or have a look at Dave Suttons web site. His site most probably have some good pics of tank configurations enabeling a closed lid and valves down.

Andy

**Freef** · 3rd July 2007, 23:59

Quote: (Originally Posted by Dave Sutton)

In any case, he's trying to figure out what size "US" tank (IE 13 cubic foot or 15 cubic foot or 6 cubic foot) will fit into the chassis, and wants to compare them to 1.0, 1.5, 2.0 litre bottles for *physical size*, and the point is that there's no way to compare other than to back-convert the US bottles to litres of water volume and then compare. Dave

In the UK we normally work in litres, but ally [not alloy!!!] tanks still seem to be measured in cu ft.

All modern back gas tanks in the UK are 232 or 300 bar rated, and steel. Ally tanks tend to be used for deco stages due to their buoyancy chatacteristics. It's easier to work out how much usable gas you have [allowing for a reserve] from a "size and pressure" [12 Litre 232 bar] tank than a 'volume' one if you are working out turn pressures.

Yankee Rebel · 4th July 2007, 00:57

Quote: (Originally Posted by Mossyback)

O.K., now I know what to go after.

As for the 72's, my local dive store owner was complaining last week because people kept dropping 72's off at her door after closing. At that time there were approximately 8 or 10 just sitting there. She didn't know how she was going to get rid of them. If you want me to tell her I'll take them if more show up I will, provided you'll take them from me. My wife gets upset when I drag home old diving equipment.

Hank

hey Hank! i know that was pointed twords Dave.. but if he doesnt want them all.. and youre letting them go for a reasonable price.. id like to get in on that as im needing more cylinders.

Yankee Rebel

**Dave Sutton** · 4th July 2007, 02:31

Quote: (Originally Posted by Mossyback)

O.K., now I know what to go after.

As for the 72's, my local dive store owner was complaining last week because people kept dropping 72's off at her door after closing. At that time there were approximately 8 or 10 just sitting there. She didn't know how she was going to get rid of them. If you want me to tell her I'll take them if more show up I will, provided you'll take them from me. My wife gets upset when I drag home old diving equipment.

Hank

I'll take as many as you can get.... and I'll send the surplus out to anyone else who wants them.

Dave

3rd July 2007, 20:00	#11 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: Need Math Lesson Quote: (Originally Posted by Stephane) Pssttttttt, Dave, you really need to buy a simple $5 calculator: 2x200=400 not 4000. Yeah, I'm a dumb shit. In any case, he's trying to figure out what size "US" tank (IE 13 cubic foot or 15 cubic foot or 6 cubic foot) will fit into the chassis, and wants to compare them to 1.0, 1.5, 2.0 litre bottles for physical size, and the point is that there's no way to compare other than to back-convert the US bottles to litres of water volume and then compare. I'll edit the post with the bad math in it so that future readers aren't challenged by my lack of decimal place awareness... Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com Last edited by Dave Sutton : 3rd July 2007 at 20:13.
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3rd July 2007, 20:01	#12 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: Need Math Lesson Quote: (Originally Posted by Mossyback) Now all I have to do is find a source for a couple of bottles for my IDA-71 that will come close to fitting inside. Hank I use Faber 2 litre steels and let the valves stick thru the bottom.... If you can find 1.5 litre bottles you can keep the regs internal. I'll buy all the galvanized steel 72's ya'll can send me. I prefer the 1980's vintage PST (Pressed Steel Tank) manufactured ones, not that I'm choosy! Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
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3rd July 2007, 21:11	#13 (permalink)
Mossyback Custom Title Allowed! Current Rebreather/s: Home Build Other Rebreather/s: Home Build Join Date: Mar 2007 Location: Southern Ontario, Canada Posts: 109	Re: Need Math Lesson Quote: (Originally Posted by Dave Sutton) I use Faber 2 litre steels and let the valves stick thru the bottom.... If you can find 1.5 litre bottles you can keep the regs internal. I'll buy all the galvanized steel 72's ya'll can send me. I prefer the 1980's vintage PST (Pressed Steel Tank) manufactured ones, not that I'm choosy! Dave O.K., now I know what to go after. As for the 72's, my local dive store owner was complaining last week because people kept dropping 72's off at her door after closing. At that time there were approximately 8 or 10 just sitting there. She didn't know how she was going to get rid of them. If you want me to tell her I'll take them if more show up I will, provided you'll take them from me. My wife gets upset when I drag home old diving equipment. Hank __________________ "Be the kind of person your dog thinks you are."
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3rd July 2007, 21:27	#14 (permalink)
Rebreatherlab Rebreatherlab Rep Current Rebreather/s: Pelagian Other Rebreather/s: Not Bought Yet Classic Kiss Pelagian Join Date: Sep 2005 Location: Thailand Posts: 203	Re: Need Math Lesson Hey Mossback, here is what I did to my IDA-71: I scrapped the left scrubber and plugged the holes in the CL, centered up the scrubber/tank retainers and re-riveted them, scrapped all plumbing, got a pair of alu 19 cu.fts (hrm. 2.7L WC 'ish) tanks from catalina, cut holes from the top of the alu box to let valves and regs protrude upwards to help offset the crappy trim. Now by doing this you will have to give away a bit of CL volume, but at least for me, (small bugger), that gave me just about what I need. further more i put the remaining CL is a sort of bungee web to help offest the inhalation effort. The draw back is that it also affect cracking of the OPV so you need to play with the tension to get right. If you need more CL volume you could put them inverted and let the handwheels stick out on the lower sides and put some bricks on top, but this ads weight to the assembly. I had trouble as it was really negative with out extra ballast, but then again I am in a 5 mil WS and am also a skinny bastard. The 13 cu.ft's (1.8L WC 'ish) are not really worth the hassle unless you are swapping just to use DIN valves. You should see my IDA btw. It has more MOD holes in it than aluminium. Sort of a Russian Swiss cheese. Andy Quote: (Originally Posted by Mossyback) Dave, I agree with you, when it comes to imperial stuff things really get out of hand. It's even worse when you live out in the country and your neighbours still talk in rods and acres. Thanks for the explanation. The local dive shop would like me to junk my old 72's and replace them with 80 cu ft aluminiums. After hearing from all of you, I think I'll just keep using them. By the way, Dave, do I have to write the test and will it count towards graduation? Thanks for the sources, Yankee Rebel. I'll get lots of use out of them. AB - your conversion examples make sense. Now all I have to do is find a source for a couple of bottles for my IDA-71 that will come close to fitting inside. Hank __________________ www.rebreatherlab.com
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3rd July 2007, 22:00	#15 (permalink)
undrh2o Chris Miller Current Rebreather/s: Other CCR Dolphin Home Build Other Rebreather/s: Inspiration Classic Other CCR Dolphin Home Build Join Date: Apr 2006 Location: Ottawa, Canada Posts: 206	Re: Need Math Lesson Quote: (Originally Posted by Rebreatherlab) Hey Mossback, here is what I did to my IDA-71: I scrapped the left scrubber and plugged the holes in the CL, centered up the scrubber/tank retainers and re-riveted them, scrapped all plumbing, got a pair of alu 19 cu.fts (hrm. 2.7L WC 'ish) tanks from catalina, cut holes from the top of the alu box to let valves and regs protrude upwards to help offset the crappy trim. Now by doing this you will have to give away a bit of CL volume, but at least for me, (small bugger), that gave me just about what I need. further more i put the remaining CL is a sort of bungee web to help offest the inhalation effort. The draw back is that it also affect cracking of the OPV so you need to play with the tension to get right. If you need more CL volume you could put them inverted and let the handwheels stick out on the lower sides and put some bricks on top, but this ads weight to the assembly. I had trouble as it was really negative with out extra ballast, but then again I am in a 5 mil WS and am also a skinny bastard. The 13 cu.ft's (1.8L WC 'ish) are not really worth the hassle unless you are swapping just to use DIN valves. You should see my IDA btw. It has more MOD holes in it than aluminium. Sort of a Russian Swiss cheese. Andy Can you post pictures? I'm curious because I've been waffling between 13 and 19 cuft tanks for my conversion as I'm worried about the valves/regs protruding below the case (I'll probably need the CL volume as I'm a big bugger) I like the idea of using valve protectors as a stand but I haven't been able source some cheaply
(Offline)

3rd July 2007, 22:40	#16 (permalink)
Rebreatherlab Rebreatherlab Rep Current Rebreather/s: Pelagian Other Rebreather/s: Not Bought Yet Classic Kiss Pelagian Join Date: Sep 2005 Location: Thailand Posts: 203	Re: Need Math Lesson Quote: (Originally Posted by undrh2o) Can you post pictures? I'm curious because I've been waffling between 13 and 19 cuft tanks for my conversion as I'm worried about the valves/regs protruding below the case (I'll probably need the CL volume as I'm a big bugger) I like the idea of using valve protectors as a stand but I haven't been able source some cheaply Sorry, my IDA-71 has retired permanently to the scrap bin since the last 3 years or so. If you really want the valves down I would suggest you try to use some similar valves as used on the inspiration. I mean valves which has the DIN on the same axis as the hand wheel. this will make better space for the 1st stage. If you use standard Thermo valves you might not be able to close the lid depending on what 1st stages you use. I might have some old pictures some where. I will have a look and post if I find anything of interest. I know a lot of big buggers who dont take so big breaths. You could easily test by gradually blocking the CL bit by bit. If you can get away with a bit restricted CL I feel this is the best way as the trim is very poor anyway. Andy __________________ www.rebreatherlab.com
(Offline)

3rd July 2007, 22:43	#17 (permalink)
Rebreatherlab Rebreatherlab Rep Current Rebreather/s: Pelagian Other Rebreather/s: Not Bought Yet Classic Kiss Pelagian Join Date: Sep 2005 Location: Thailand Posts: 203	Re: Need Math Lesson Quote: (Originally Posted by undrh2o) Can you post pictures? I'm curious because I've been waffling between 13 and 19 cuft tanks for my conversion as I'm worried about the valves/regs protruding below the case (I'll probably need the CL volume as I'm a big bugger) I like the idea of using valve protectors as a stand but I haven't been able source some cheaply Or have a look at Dave Suttons web site. His site most probably have some good pics of tank configurations enabeling a closed lid and valves down. Andy __________________ www.rebreatherlab.com
(Offline)

3rd July 2007, 23:59	#18 (permalink)
Freef Custom Title Disallowed! Current Rebreather/s: Dolphin Other Rebreather/s: Dolphin Join Date: Jan 2006 Location: Land of the Freef, UK. Posts: 1,427	Re: Need Math Lesson Quote: (Originally Posted by Dave Sutton) In any case, he's trying to figure out what size "US" tank (IE 13 cubic foot or 15 cubic foot or 6 cubic foot) will fit into the chassis, and wants to compare them to 1.0, 1.5, 2.0 litre bottles for physical size, and the point is that there's no way to compare other than to back-convert the US bottles to litres of water volume and then compare. Dave In the UK we normally work in litres, but ally [not alloy!!!] tanks still seem to be measured in cu ft. All modern back gas tanks in the UK are 232 or 300 bar rated, and steel. Ally tanks tend to be used for deco stages due to their buoyancy chatacteristics. It's easier to work out how much usable gas you have [allowing for a reserve] from a "size and pressure" [12 Litre 232 bar] tank than a 'volume' one if you are working out turn pressures. __________________ David. Diving the mahogany rebreather.
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4th July 2007, 00:57	#19 (permalink)
Yankee Rebel Custom Title Allowed! Current Rebreather/s: Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Jan 2006 Location: California Posts: 147	Re: Need Math Lesson Quote: (Originally Posted by Mossyback) O.K., now I know what to go after. As for the 72's, my local dive store owner was complaining last week because people kept dropping 72's off at her door after closing. At that time there were approximately 8 or 10 just sitting there. She didn't know how she was going to get rid of them. If you want me to tell her I'll take them if more show up I will, provided you'll take them from me. My wife gets upset when I drag home old diving equipment. Hank hey Hank! i know that was pointed twords Dave.. but if he doesnt want them all.. and youre letting them go for a reasonable price.. id like to get in on that as im needing more cylinders. Yankee Rebel
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4th July 2007, 02:31	#20 (permalink)
Dave Sutton Diveshop of Horrors Current Rebreather/s: Sport Kiss MK 15.X rEvo Other CCR Azimuth Home Build Other Rebreather/s: Evolution Megalodon rEvo Other CCR Azimuth Home Build Join Date: Jun 2006 Location: Narragansett, Rhode Island and Hackettstown, New Jersey Posts: 2,907	Re: Need Math Lesson Quote: (Originally Posted by Mossyback) O.K., now I know what to go after. As for the 72's, my local dive store owner was complaining last week because people kept dropping 72's off at her door after closing. At that time there were approximately 8 or 10 just sitting there. She didn't know how she was going to get rid of them. If you want me to tell her I'll take them if more show up I will, provided you'll take them from me. My wife gets upset when I drag home old diving equipment. Hank I'll take as many as you can get.... and I'll send the surplus out to anyone else who wants them. Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
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