Composite tanks bouyancy

Mikel-Deko · 17th January 2008, 09:37

Quote:

(Originally Posted by paulraymaekers)

Hi Mikel, the mini rEvo titanium, equipped with 2 liter carbon tanks, is less then 21kg..

paul

Hi,

I've been playing with the idea of mounting 2 liter carbon tanks in my inspi.
The rig will be some good 6-7 kgs lighter in dry. My back will be happy with that.

But my question is how this extra buoyancy will affect my weight belt need.

If i take some kilos off and, at the same time, i put some positive buoyancy in, i would need a lot more kilos in the weight belt... Is this RIGHT?

Regards,

Mikel

Brainx3 · 17th January 2008, 10:49

Hi,

I'm interested to buy such tanks. Can you please let me know about where are they sold?

Best Regards. Wael

Mikel-Deko · 17th January 2008, 13:16

Hi
I don't know if Paul Raymaeker (www.revo-rebreather.com) sell them.
But you can find them here: Tauchen - Cave, Nitrox, Rebreather Ausbildung, Tec Ausrüstung, Reisen
Best
Mikel

Blomman · 18th January 2008, 10:15

I think your back will be happier if you remove the weights from your belt and put them elsewhere instead. You can put 4kg on the top of the machine, 2+2kg in the "trim-pockets" of the AP 22kg wing, 2kg on each tankband and then you have some space next to the first stages as well. I managed to put 14kg in my machine so no belt was needed. This was a back-saver for me during some long wreckdives a few days ago.

// Blomman

chrismc · 18th January 2008, 10:49

Composite tanks are used widely on the surface, due to their lightness, but rarely underwater, due to them floating.

They have thin walls so will be very similar in volume displacement to your steel tanks. You will need the same weight to get descend, so it will need to go somewhere.

in effect your taking weight off the cylinders and adding the same weight to your belt.

grahamsp · 20th January 2008, 04:38

Quote: (Originally Posted by chrismc)

Composite tanks are used widely on the surface, due to their lightness, but rarely underwater, due to them floating.

I've been told (by whom I cannot recall) that the reason composites are not approved for diving is the risk of delamination.

Does anyone know if:

a. Composite cylinders have in fact been approved for diving anywhere in the world;

b. There is a risk of delamination if used for diving.

Graham

andrespp · 20th January 2008, 07:47

Quote: (Originally Posted by grahamsp)

I've been told (by whom I cannot recall) that the reason composites are not approved for diving is the risk of delamination.

Does anyone know if:

a. Composite cylinders have in fact been approved for diving anywhere in the world;

b. There is a risk of delamination if used for diving.

Graham

I work pretty close to a firefighters station; and the tanks they use for the fire scba equipments have an interior metal recipient of steel, with rather thin walls, and then the fiber laminates all around the metal core.

The usual charging pressure is 300 bar, the tanks are about 7 liters ones, and should say that the full tanks weight is less than 5 kg.

One of the guys there is a OC recreational diver, and told me that he tried to use a twinset made out of two of these tanks to dive. His outcome was :

1. They have terrific buoyancy.

2. With less than half dozen uses, the wrapping fiber around began to deteriorate. Did not delaminate, but it became very sticky .

3. The tank wrapping is very prone to be damaged in a diving environment (boat, other tanks, etc. )

Find below an old thread form another forum discussing this very same issue:

composite cylinders [Archive] - ScubaBoard

Stephane · 20th January 2008, 08:18

Quote:

a. Composite cylinders have in fact been approved for diving anywhere in the world;

b. There is a risk of delamination if used for diving.

Hi Graham,

a: Yes, Worthington has some carbon cylinders made up for scuba diving. They are sold by Carbondive in Europe. But they start at 7l.

b: my OC buddy had a twin 12l 300b for over a year and there were no signs of delamination. He splitted it and I bought one cylinder for bailout. Another friend has two 7l carbon tanks and they are fine too. I guess these cylinders are wrapped with a special glue that protects them.

Martin from Tecme in Germany has some nice 2l aluminium-carbon cylinders (1,8kg without valve). I had two of them on the rEvo1. The only drawback is that they have a small conical valve thread so you can't take them to travel by plane.

Skipbreather · 20th January 2008, 17:31

Quote: (Originally Posted by grahamsp)

I've been told (by whom I cannot recall) that the reason composites are not approved for diving is the risk of delamination.

Does anyone know if:

a. Composite cylinders have in fact been approved for diving anywhere in the world;

b. There is a risk of delamination if used for diving.

Graham

Luxfer has been selling 300 bar hoop wrap composite scuba tanks for several years now. They are in limited distribution but have no delamination issues that I’ve heard of. I’ve been using 4.7 liter 300 bar Luxfer SCBA tanks that are of *very* similar construction for years (their L45W) as bail out tanks and have had zero problems.

Mikel-Deko · 21st January 2008, 07:56

Quote: (Originally Posted by Stephane)

Hi Graham,

a: Yes, Worthington has some carbon cylinders made up for scuba diving. They are sold by Carbondive in Europe. But they start at 7l.

b: my OC buddy had a twin 12l 300b for over a year and there were no signs of delamination. He splitted it and I bought one cylinder for bailout. Another friend has two 7l carbon tanks and they are fine too. I guess these cylinders are wrapped with a special glue that protects them.

Martin from Tecme in Germany has some nice 2l aluminium-carbon cylinders (1,8kg without valve). I had two of them on the rEvo1. The only drawback is that they have a small conical valve thread so you can't take them to travel by plane.

Hi Stephane,
Those Tecme's tanks are the ones that i've been looking.
How they work untherwater? floting a lot? need any especial atention?
Thanks for your answer.
Mikel

17th January 2008, 09:37	#1 (permalink)
Mikel-Deko Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 452	Composite tanks bouyancy Quote: (Originally Posted by paulraymaekers) Hi Mikel, the mini rEvo titanium, equipped with 2 liter carbon tanks, is less then 21kg.. paul Hi, I've been playing with the idea of mounting 2 liter carbon tanks in my inspi. The rig will be some good 6-7 kgs lighter in dry. My back will be happy with that. But my question is how this extra buoyancy will affect my weight belt need. If i take some kilos off and, at the same time, i put some positive buoyancy in, i would need a lot more kilos in the weight belt... Is this RIGHT? Regards, Mikel __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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17th January 2008, 10:49	#2 (permalink)
Brainx3 Totally Submerged Current Rebreather/s: Inspiration Vision Other Rebreather/s: Inspiration Classic Join Date: Aug 2007 Location: International Waters Posts: 292	Re: Composite tanks bouyancy Hi, I'm interested to buy such tanks. Can you please let me know about where are they sold? Best Regards. Wael __________________ The depth of life cannot be measured in Bars, nor can the sea of lies, that lies within. Sooner or later I'll be cracking your market and end your game. *I don't take crap for an answer...*
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17th January 2008, 13:16	#3 (permalink)
Mikel-Deko Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 452	Re: Composite tanks bouyancy Hi I don't know if Paul Raymaeker (www.revo-rebreather.com) sell them. But you can find them here: Tauchen - Cave, Nitrox, Rebreather Ausbildung, Tec Ausrüstung, Reisen Best Mikel __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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18th January 2008, 10:15	#4 (permalink)
Blomman Helium is addictive! Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2006 Location: Sweden Posts: 151	Re: Composite tanks bouyancy I think your back will be happier if you remove the weights from your belt and put them elsewhere instead. You can put 4kg on the top of the machine, 2+2kg in the "trim-pockets" of the AP 22kg wing, 2kg on each tankband and then you have some space next to the first stages as well. I managed to put 14kg in my machine so no belt was needed. This was a back-saver for me during some long wreckdives a few days ago. // Blomman
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18th January 2008, 10:49	#5 (permalink)
chrismc New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Sep 2005 Location: North west, uk Posts: 61	Re: Composite tanks bouyancy Composite tanks are used widely on the surface, due to their lightness, but rarely underwater, due to them floating. They have thin walls so will be very similar in volume displacement to your steel tanks. You will need the same weight to get descend, so it will need to go somewhere. in effect your taking weight off the cylinders and adding the same weight to your belt.
(Online)

20th January 2008, 04:38	#6 (permalink)
grahamsp New Member Current Rebreather/s: Evolution Other Rebreather/s: Join Date: Jun 2005 Location: Sydney, Australia Posts: 115	Re: Composite tanks bouyancy Quote: (Originally Posted by chrismc) Composite tanks are used widely on the surface, due to their lightness, but rarely underwater, due to them floating. I've been told (by whom I cannot recall) that the reason composites are not approved for diving is the risk of delamination. Does anyone know if: a. Composite cylinders have in fact been approved for diving anywhere in the world; b. There is a risk of delamination if used for diving. Graham
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20th January 2008, 07:47	#7 (permalink)
andrespp New Member Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: May 2007 Location: Cádiz (Spain) Posts: 47	Re: Composite tanks bouyancy Quote: (Originally Posted by grahamsp) I've been told (by whom I cannot recall) that the reason composites are not approved for diving is the risk of delamination. Does anyone know if: a. Composite cylinders have in fact been approved for diving anywhere in the world; b. There is a risk of delamination if used for diving. Graham I work pretty close to a firefighters station; and the tanks they use for the fire scba equipments have an interior metal recipient of steel, with rather thin walls, and then the fiber laminates all around the metal core. The usual charging pressure is 300 bar, the tanks are about 7 liters ones, and should say that the full tanks weight is less than 5 kg. One of the guys there is a OC recreational diver, and told me that he tried to use a twinset made out of two of these tanks to dive. His outcome was : 1. They have terrific buoyancy. 2. With less than half dozen uses, the wrapping fiber around began to deteriorate. Did not delaminate, but it became very sticky . 3. The tank wrapping is very prone to be damaged in a diving environment (boat, other tanks, etc. ) Find below an old thread form another forum discussing this very same issue: composite cylinders [Archive] - ScubaBoard
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20th January 2008, 08:18	#8 (permalink)
Stephane Stéphane Acounis Current Rebreather/s: rEvo Other Rebreather/s: rEvo Join Date: Nov 2005 Location: Nantes - France Posts: 769	Re: Composite tanks bouyancy Quote: a. Composite cylinders have in fact been approved for diving anywhere in the world; b. There is a risk of delamination if used for diving. Hi Graham, a: Yes, Worthington has some carbon cylinders made up for scuba diving. They are sold by Carbondive in Europe. But they start at 7l. b: my OC buddy had a twin 12l 300b for over a year and there were no signs of delamination. He splitted it and I bought one cylinder for bailout. Another friend has two 7l carbon tanks and they are fine too. I guess these cylinders are wrapped with a special glue that protects them. Martin from Tecme in Germany has some nice 2l aluminium-carbon cylinders (1,8kg without valve). I had two of them on the rEvo1. The only drawback is that they have a small conical valve thread so you can't take them to travel by plane. __________________ Stéphane
(Online)

20th January 2008, 17:31	#9 (permalink)
Skipbreather Reads the fine print Current Rebreather/s: Megalodon Home Build Other Rebreather/s: Not Bought Yet MK 15.X Home Build Join Date: Mar 2005 Location: Chicago, Illinois, USA Posts: 557	Re: Composite tanks bouyancy Quote: (Originally Posted by grahamsp) I've been told (by whom I cannot recall) that the reason composites are not approved for diving is the risk of delamination. Does anyone know if: a. Composite cylinders have in fact been approved for diving anywhere in the world; b. There is a risk of delamination if used for diving. Graham Luxfer has been selling 300 bar hoop wrap composite scuba tanks for several years now. They are in limited distribution but have no delamination issues that I’ve heard of. I’ve been using 4.7 liter 300 bar Luxfer SCBA tanks that are of very similar construction for years (their L45W) as bail out tanks and have had zero problems. __________________ "Entropy RULES! Enjoy the interim."
(Online)

21st January 2008, 07:56	#10 (permalink)
Mikel-Deko Custom Title Allowed! Current Rebreather/s: Inspiration Classic Other CCR Other Rebreather/s: Other CCR Join Date: Jul 2005 Location: Basque Country -Sp- Posts: 452	Re: Composite tanks bouyancy Quote: (Originally Posted by Stephane) Hi Graham, a: Yes, Worthington has some carbon cylinders made up for scuba diving. They are sold by Carbondive in Europe. But they start at 7l. b: my OC buddy had a twin 12l 300b for over a year and there were no signs of delamination. He splitted it and I bought one cylinder for bailout. Another friend has two 7l carbon tanks and they are fine too. I guess these cylinders are wrapped with a special glue that protects them. Martin from Tecme in Germany has some nice 2l aluminium-carbon cylinders (1,8kg without valve). I had two of them on the rEvo1. The only drawback is that they have a small conical valve thread so you can't take them to travel by plane. Hi Stephane, Those Tecme's tanks are the ones that i've been looking. How they work untherwater? floting a lot? need any especial atention? Thanks for your answer. Mikel __________________ Mikel-Deko Basque Country www.olatu.net "DIR is the nanny state for divers who cannot think on their own" Ron Micjan
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