A solution for Butt-heavy rebreather divers

cedricverdier · 11th January 2006, 08:42

Hi all,

For those who are butt-heavy with a rebreather, a very efficient way to improve the trim is to mount the in-board tanks upright instead of upside down. Obviously, it's only valid for the "open-frame" rebreathers like the Megalodon, the Prism (no cover), the KISS or some homebuilts.
The weight of the tank valves and the regulator 1st stages are now on top of the unit instead of on the bottom.

Benefits:
- The balance of the unit makes most of the trim weights unnecessary.

- After re-routing and shortening the LP and HP hoses, the configuration becomes a lot simpler (and streamlined?)

- It becomes easier to spot any leak from a 1st stage (specialy for solo divers...)

- The unit is more stable at sitting upright on a boat, and the valves/regulators are less exposed to damage or leak.

Disadvantages:
- The tank valves are less accessible (but the diver can still reach them, like for double tanks) and it takes a little bit more time to shut them off. As the valves are only slightly open, it's only a matter of a couple of seconds. A strong shock dislodging the 1st stage is still a possibility.

- The valves are more exposed in an overhead environment (but the trim being much better, the diver gets a better horizontal position that should avoid to bang the valves on the ceiling).

So if you have any experience on this kind of cylinder configuration, feel free to add your comments on the list of benefits/disadvantages.

Cheers

decoweenie · 11th January 2006, 10:11

Quote: (Originally Posted by cedricverdier)

So if you have any experience on this kind of cylinder configuration, feel free to add your comments on the list of benefits/disadvantages.

Been doing upright tanks with the Classic-KISS close to 4 years, and with the Sport-KISS since day 1, I could share some random personal experience (on top of what Cedric already mentioned):

I rotate the tank valves forward by 45-deg in order to get to them even easier. I could reach the valves easier than on my twinset.
I use almost the same hose configuration as on my twin set (i.e. wing inflator, SPG) with some additional hoses (i.e. to ADV, to O2 solenoid/orifice, O2 SPG)
Upright tank valve config is slight more protected if you tend to stand the unit up on the boat.
You need 90-deg valves (i.e. standard OC), and not the 180-deg valves (i.e. Insp valve)
No need for extra-long hoses any more so could swap easily with OC hoses.
Re-fill tanks without taking them off is easier. I just carry the entire rig to the blending area, take the regs off and refill.
Need the correct length tanks to keep the weight of the entire rig off the scrubber

I will add if I think of more later...

***Beanie*** · 11th January 2006, 10:18

hmmm this config might haelp my current setup could save a bit of travelling weight as well lose the inspo maifold and some hoses.

might look into this tonight

decoweenie · 11th January 2006, 10:22

Quote: (Originally Posted by Beanie)

hmmm this config might haelp my current setup could save a bit of travelling weight as well lose the inspo maifold and some hoses.

Don't forget to consider what I said about not using the standard APV tank valve since:

If you keep the tank valves perfectly perpendicular from you to protect the reg (will be between tank and scrubber), then it will more difficult to reach the valves.
If you rotate the valves forward by 45-deg for easier access, then the regs are facing 45-deg backward and more awkward to route hose as well as more exposed.

paulraymaekers · 11th January 2006, 10:37

???? and what about adding some top-weight???

drysuitdiving, I need some extra weight anyway!

regards
paul

***Beanie*** · 11th January 2006, 10:50

Quote: (Originally Posted by paulraymaekers)

???? and what about adding some top-weight???

drysuitdiving, I need some extra weight anyway!

regards
paul

I only need weight in the sea not sure about in a wetsuit but most likely not also the rig I'm bodging together doesn't have a place for top weight yet.

TR300 · 11th January 2006, 11:00

Hi Phi,

whats about small cylinders (like 20cuf or 1.5 Liter) ?
On mine Rebreather they are then very deep and not recheable.

I think size up to 3 Liter will perfect then.

Holger

decoweenie · 11th January 2006, 11:06

Quote: (Originally Posted by TR300)

whats about small cylinders (like 20cuf or 1.5 Liter) ?
On mine Rebreather they are then very deep and not recheable.

I think size up to 3 Liter will perfect then.

Yes, the smallest tank size I found that I could reach the valves, and the tanks touch the floor same as the KISS scrubbers, is the 3L aluminum.

Anything smaller (2.5L SS, 2L SS, 14cf AL, etc) is just too short to be practical and look nice/balance.

The 3L aluminum tanks I am using is the new (introduced 3 years ago) Luxfer 3L. The older Luxfer 3L tanks are a little shorter.

Scubascooby · 11th January 2006, 12:11

Quote: (Originally Posted by cedricverdier)

Hi all,

For those who are butt-heavy with a rebreather, a very efficient way to improve the trim is to mount the in-board tanks upright instead of upside down.

I asked about de-inverting the tanks in the KISS section but after I posted
it also occurred to me that this would help to prevent the head-up attitude.

I've not dived the unit yet and I am bit concerned that the valves might not
be easy to access but I can only try it, after the course I think.

Peter

Marc T · 11th January 2006, 12:42

[quote=cedricverdier]Hi all,

For those who are butt-heavy with a rebreather, a very efficient way to improve the trim is to mount the in-board tanks upright instead of upside down. Obviously, it's only valid for the "open-frame" rebreathers like the Megalodon, the Prism (no cover), the KISS or some homebuilts.
The weight of the tank valves and the regulator 1st stages are now on top of the unit instead of on the bottom.

Benefits:
- The balance of the unit makes most of the trim weights unnecessary.

- After re-routing and shortening the LP and HP hoses, the configuration becomes a lot simpler (and streamlined?)

- It becomes easier to spot any leak from a 1st stage (specialy for solo divers...)

- The unit is more stable at sitting upright on a boat, and the valves/regulators are less exposed to damage or leak.

I agree to all these benefits, but add one which is the best one for me is that you can use big tanks ( never under 6 liters but never more than 12 for me ) of course its a rather big unit, but not a monster based on EDO04 ( id Rebreather 80 like ) turned into mCCR.

And my Back up Rebreather is feeded by the same back mounted dil tanks, 3 liters o2 tanks are side mounted

An other benefit is that the valve position is always the same behind your back either with 6 , 7 or 12 but in this case the Rebreather dont tuch the ground.

Ok its only for big cave diving, too heavy to walk with, and on a boat hum hum!

11th January 2006, 08:42	#1 (permalink)
cedricverdier S21 M.I.B. Current Rebreather/s: Evolution Megalodon Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Worldwide! Posts: 488	A solution for Butt-heavy rebreather divers Hi all, For those who are butt-heavy with a rebreather, a very efficient way to improve the trim is to mount the in-board tanks upright instead of upside down. Obviously, it's only valid for the "open-frame" rebreathers like the Megalodon, the Prism (no cover), the KISS or some homebuilts. The weight of the tank valves and the regulator 1st stages are now on top of the unit instead of on the bottom. Benefits: - The balance of the unit makes most of the trim weights unnecessary. - After re-routing and shortening the LP and HP hoses, the configuration becomes a lot simpler (and streamlined?) - It becomes easier to spot any leak from a 1st stage (specialy for solo divers...) - The unit is more stable at sitting upright on a boat, and the valves/regulators are less exposed to damage or leak. Disadvantages: - The tank valves are less accessible (but the diver can still reach them, like for double tanks) and it takes a little bit more time to shut them off. As the valves are only slightly open, it's only a matter of a couple of seconds. A strong shock dislodging the 1st stage is still a possibility. - The valves are more exposed in an overhead environment (but the trim being much better, the diver gets a better horizontal position that should avoid to bang the valves on the ceiling). So if you have any experience on this kind of cylinder configuration, feel free to add your comments on the list of benefits/disadvantages. Cheers __________________ Cedric Verdier PADI Course Director, ANDI-IANTD-PSAI-TDI-DSAT-DAN-NAUI-CMAS Instructor Trainer Trimix (CCR and OC) and Cave Diving Instructor Trainer www.CedricVerdier.com DIRrebreather member
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11th January 2006, 10:11	#2 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,510	Re: A solution for Butt-heavy rebreather divers Quote: (Originally Posted by cedricverdier) So if you have any experience on this kind of cylinder configuration, feel free to add your comments on the list of benefits/disadvantages. Been doing upright tanks with the Classic-KISS close to 4 years, and with the Sport-KISS since day 1, I could share some random personal experience (on top of what Cedric already mentioned): I rotate the tank valves forward by 45-deg in order to get to them even easier. I could reach the valves easier than on my twinset. I use almost the same hose configuration as on my twin set (i.e. wing inflator, SPG) with some additional hoses (i.e. to ADV, to O2 solenoid/orifice, O2 SPG) Upright tank valve config is slight more protected if you tend to stand the unit up on the boat. You need 90-deg valves (i.e. standard OC), and not the 180-deg valves (i.e. Insp valve) No need for extra-long hoses any more so could swap easily with OC hoses. Re-fill tanks without taking them off is easier. I just carry the entire rig to the blending area, take the regs off and refill. Need the correct length tanks to keep the weight of the entire rig off the scrubber I will add if I think of more later... __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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11th January 2006, 10:18	#3 (permalink)
*Beanie* Politeness officer Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,157	Re: A solution for Butt-heavy rebreather divers hmmm this config might haelp my current setup could save a bit of travelling weight as well lose the inspo maifold and some hoses. might look into this tonight __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk www.divelife.co.uk
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11th January 2006, 10:22	#4 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,510	Re: A solution for Butt-heavy rebreather divers Quote: (Originally Posted by Beanie) hmmm this config might haelp my current setup could save a bit of travelling weight as well lose the inspo maifold and some hoses. Don't forget to consider what I said about not using the standard APV tank valve since: If you keep the tank valves perfectly perpendicular from you to protect the reg (will be between tank and scrubber), then it will more difficult to reach the valves. If you rotate the valves forward by 45-deg for easier access, then the regs are facing 45-deg backward and more awkward to route hose as well as more exposed. __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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11th January 2006, 10:37	#5 (permalink)
paulraymaekers rEvo's daddy Current Rebreather/s: rEvo Other CCR Home Build Other Rebreather/s: rEvo Other CCR Home Build Join Date: May 2005 Location: belgium Posts: 1,365	Re: A solution for Butt-heavy rebreather divers ???? and what about adding some top-weight??? drysuitdiving, I need some extra weight anyway! regards paul __________________ www.rEvo-rebreathers.com .... the earth is flat, Elvis is alive, and radial scrubbers give longer dwell time than axials...
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11th January 2006, 10:50	#6 (permalink)
*Beanie* Politeness officer Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,157	Re: A solution for Butt-heavy rebreather divers Quote: (Originally Posted by paulraymaekers) ???? and what about adding some top-weight??? drysuitdiving, I need some extra weight anyway! regards paul I only need weight in the sea not sure about in a wetsuit but most likely not also the rig I'm bodging together doesn't have a place for top weight yet. __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk www.divelife.co.uk
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11th January 2006, 11:00	#7 (permalink)
TR300 Home of the TR300 Current Rebreather/s: Other CCR Dolphin Other SCR Home Build Other Rebreather/s: Not Bought Yet Other CCR Dolphin Other SCR Home Build Join Date: Jan 2005 Location: Weinheim, Germany Posts: 181	Re: A solution for Butt-heavy rebreather divers Hi Phi, whats about small cylinders (like 20cuf or 1.5 Liter) ? On mine Rebreather they are then very deep and not recheable. I think size up to 3 Liter will perfect then. Holger __________________ If it makes bubbles it means its brocken Visit: www.tr300.com, Missions: www.rebreatherteam.de
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11th January 2006, 11:06	#8 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,510	Re: A solution for Butt-heavy rebreather divers Quote: (Originally Posted by TR300) whats about small cylinders (like 20cuf or 1.5 Liter) ? On mine Rebreather they are then very deep and not recheable. I think size up to 3 Liter will perfect then. Yes, the smallest tank size I found that I could reach the valves, and the tanks touch the floor same as the KISS scrubbers, is the 3L aluminum. Anything smaller (2.5L SS, 2L SS, 14cf AL, etc) is just too short to be practical and look nice/balance. The 3L aluminum tanks I am using is the new (introduced 3 years ago) Luxfer 3L. The older Luxfer 3L tanks are a little shorter. __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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11th January 2006, 12:11	#9 (permalink)
Scubascooby Better Off Out of the EU Current Rebreather/s: Classic Kiss Other Rebreather/s: Join Date: Nov 2005 Location: Great Britain Posts: 328	Re: A solution for Butt-heavy rebreather divers Quote: (Originally Posted by cedricverdier) Hi all, For those who are butt-heavy with a rebreather, a very efficient way to improve the trim is to mount the in-board tanks upright instead of upside down. I asked about de-inverting the tanks in the KISS section but after I posted it also occurred to me that this would help to prevent the head-up attitude. I've not dived the unit yet and I am bit concerned that the valves might not be easy to access but I can only try it, after the course I think. Peter __________________ "dove" is NOT the past tense of "dive"
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11th January 2006, 12:42	#10 (permalink)
Marc T hell is in the details Current Rebreather/s: RB80 / Clone Home Build Other Rebreather/s: Not Bought Yet RB80 / Clone Home Build Join Date: Sep 2005 Location: FRANCE Carcassonne Posts: 439	Re: A solution for Butt-heavy rebreather divers [quote=cedricverdier]Hi all, For those who are butt-heavy with a rebreather, a very efficient way to improve the trim is to mount the in-board tanks upright instead of upside down. Obviously, it's only valid for the "open-frame" rebreathers like the Megalodon, the Prism (no cover), the KISS or some homebuilts. The weight of the tank valves and the regulator 1st stages are now on top of the unit instead of on the bottom. Benefits: - The balance of the unit makes most of the trim weights unnecessary. - After re-routing and shortening the LP and HP hoses, the configuration becomes a lot simpler (and streamlined?) - It becomes easier to spot any leak from a 1st stage (specialy for solo divers...) - The unit is more stable at sitting upright on a boat, and the valves/regulators are less exposed to damage or leak. I agree to all these benefits, but add one which is the best one for me is that you can use big tanks ( never under 6 liters but never more than 12 for me ) of course its a rather big unit, but not a monster based on EDO04 ( id Rebreather 80 like ) turned into mCCR. And my Back up Rebreather is feeded by the same back mounted dil tanks, 3 liters o2 tanks are side mounted An other benefit is that the valve position is always the same behind your back either with 6 , 7 or 12 but in this case the Rebreather dont tuch the ground. Ok its only for big cave diving, too heavy to walk with, and on a boat hum hum!
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