IDA-71 Questions / Ideas...

divingtoors · 26th December 2006, 05:52

Hello there avid homebuilders..

I am in process of converting my IDA-71 to a MCCR, KISS type rebreather.

(Thanx for the inspration Dave!)

I would appreciate if somebody could help with the following questions:

1) In regards to the +/- 4Kg (8LBS) of lead ballast that needs to be added and is fixed to the lid of the IDA-71 to counteract the buoyancy of the counterlungs, can the lead ballast be fastened to the "chassis" of the IDA, under the counterlung, instead of onto the lid, over the counterlung?
If not, please give a the reason as I think that by doing this, the lid will be kept light and easy to operate, and the lead ballast will have minimum effect on reducing the counterlung volume, as the counterlung will always have a tendency to float away from the chassis, in effect then floating away from the lead ballast.

2) Under the curent scrubbers, and O2 cilinder, there is a lot of "dead space" where all types of interresting things can be placed and fixed, i.e battery canisters etc...
Has anybody thought of building / designing 2 x bigger (longer) scrubbers that will lie in the place where the current "small" metalic scrubbers lie, but extended so that the scrubber length totally fills the "dead space" under the current scrubbers. By rough calculation I estimate it will almost give you a "third" scrubber (volume wise) which will deffinately extend bottom time and possibly even depth with the IDA-71, as the total scrubber size will then almost be equal to the IDA-72 giant scrubber. To build a axial scrubber with thread to lock and screw into the place where the current scrubbers screw into, cannot be that difficult. How much would WOB be influenced by doing this?

Your input and thought are appreciated

Best regards

Johan

GKAM · 26th December 2006, 07:39

Hi Johan,

The IDA 71 needs about 4kg mounted as high as possible to counterbalance the CL buoyancy. At first, I did copy Dave's suggestion and added the weight under the lid. However, it soon became apparent that the reduction in available space for the CL expansion caused a problem for me. Perhaps my hose routing was also to blame, but now I have moved the weights outside the unit. This has greatly improved things not only wrt the CL but has also made the core unit lighter and hence more easy to manage. The ideal placement for the weights is as high up on the harness. Right where Spock used to apply the Vulcan death grip

On the scrubber issue, I simply would not mess with the Russian scrubbers. They are simple, robust and well engineered. Use one scrubber if you intend to go no deeper than +/- 50m or keep both if you intend to dive the unit deeper. The space you see right now in your unmodified unit will most likely be taken up by the time you finished your mod.

I'm very happy with my unit and dive it very often. Easy to setup and maintain and fun to dive. The only drawback is the lack of watertrap.

Good luck in your mods!

/GKAM

mverick · 26th December 2006, 12:20

For a 72 scrubber. Just start with a 72.

On the 71, I'd use both scrubbers. Always. Not needed. But good if you start working hard. And sorb is cheaper then a pine box.

I mounted my weights on top of box outside with zip ties.

**Dave Sutton** · 26th December 2006, 22:34

For the lead, simply tie it to the lid. Use plastic wire-ties to hold the weights to the "gill slots" on the lid over the counterlung. The counterlung will be flexed against the lead, does not affect it at all, and the rig when the lid is removed is easier to handle than if the lead is in the chassis. There shoud be NO impact on the effective counterlung volume. I have also seen divers place 2kg weights right on the shoulder harnesses, as close to the rig as possible. I do this on my Mark-15, actually.

Don't reinvent the wheel with the scrubbers. Leave them alone. Use them as they are, and forget them. The Russians made them "just right". I also suggest using both scrubbr and carrying all diluent as a small stage bottle, fed to the unit thru a quick connect. Makes life easy, and you will want suit/wing/bailou gas carried as an offboard bottle anyhow. Why pretend to carry diluent internally when you are going to carry an external bottle in any event?

Dave Sutton

divingtoors · 27th December 2006, 06:18

Hi

What I have done is as follows:

I have put a 2L 200Bar cylinder for O2 in place of the supplied Russian O2 cylinder & valve.
I have a KISS valve that will supply O2 to the counterlung

Then I have taken 2 x 3L 200Bar Aluminium cylinders and fixed them to the chassis (offboard) with G-Clamps. The cylinders basically sit on the outside of the IDA-71 and looks almost like the rocket man

The idea is to have the one 3L cylinder with diluent (offboard), and the other 3L cylinder as suit inflation / Wing inflation and 1st bailout (also offboard)
(A regulator coupled to the suit inflation cylinder will be bungeed around my neck)
I will then be able to run either one or two scrubbers with no problem or conversion at all.

I plan to make a dummy scrubber from PVC piping to act as a "place keeper" for the removed scrubber, as i opted not to remove al the guts in the IDA, but only the "guts" where it affected the O2 cylinder. It looks great and works very well too, still keeping some of the original IDA-71 "flavour"

My idea is to use Nitrox 32-50 depending on my maximum depth, as suit inflation. This will then double as a convenient..I call it a primary bailout, (for sanity breaths ) before switching to the main bailout (which will be clipped to the harnass) in the event that it will be needed.

The unit is a bit heavy on land, but will be tested in water soon to see the net result.

I am currently working on the PPO2 metering.
I would like to know where the optimum placing of the P-connectors would be, as I intend to run a 2/3 sensor display and then later on an integrated
VR3/HS Explorer. This means that the male P-connector will be quite long and I dont think the IDA CL is deep enough to accomodate a 2/3-sensor P-connector

Any ideas and views that can assist?

Regards

Johan

**Dave Sutton** · 27th December 2006, 14:35

You don't need to make a dummy scrubber, you can simply plug the unused counterlung ports with plugs from McMaster-Carr. These are the rubber plugs with the flip-over lever to exand, used in the back of a small boat to let water out. You can imagine it. hey work just perfectly. I get them at the hardware store, with brass or stainless metal.

Put the P-Connector on the SIDE of the counterlung, divers right shoulder. This way a long cell-probe does not "tent pole" the counterlung. I make also a folding cell probe to allow the cells to lay flat inside the lung, but a solid probe is easier to make and the P Connector on the side of the lung is fine.

I think you have too much stuff attached to the chassis. I would remove the two "mounted" diluent cylinders and replace them with one cylinder carried as a stage bottle and connected thru a quick disconnect line to the rig. This way you can carry any size cylinder for the desired dive, and the rig itself is easier to carry. Unsnap the external bottle when climbing a ladder and hang it on an equipment line. Trust me, this will work a lot better and you will not even know it is there.

Dave

zepp · 27th December 2006, 15:10

I have weights cable tied to the outside and use a three cell holder which plugs into a p port made by John Routley AKA Narked at ninety.

mverick · 27th December 2006, 17:10

I use 2 cells, one for a po2 meter. Single read and one for a VR3 or HSE. But the HSE hasn't ever worked. And I'm not happy with the VR3's alog. If you do a dil flush and one or the other isn't jiving with the dil flush. Guess what, read the other. I believe in 3 cells for voting logic. But for mental logic I stick with 2.

I'd side sling a al40 and route it with a quick connect to the unit for your dil. Then you have a good sized bailout enough for your wing and suit and you also don't have a rig as wide as a elephant.

LOL

But, do as you like. They are toy's and your way will work fine.

teomannaskali · 30th December 2007, 18:01

Has anyone ever cut open an ida cannister? I would really like to see the inside. Teoman

**Dave Sutton** · 30th December 2007, 18:44

Quote: (Originally Posted by zepp)

I have weights cable tied to the outside and use a three cell holder which plugs into a p port made by John Routley AKA Narked at ninety.

Cable tie them inside... you'll never know the difference and it'll look far better.

Another user of a properly designed sensor holder... the ever-popular DS-3. Wonder where that part number came from.....

Dave

26th December 2006, 05:52	#1 (permalink)
divingtoors RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Mar 2006 Location: Cape Town Posts: 103	IDA-71 Questions / Ideas... Hello there avid homebuilders.. I am in process of converting my IDA-71 to a MCCR, KISS type rebreather. (Thanx for the inspration Dave!) I would appreciate if somebody could help with the following questions: 1) In regards to the +/- 4Kg (8LBS) of lead ballast that needs to be added and is fixed to the lid of the IDA-71 to counteract the buoyancy of the counterlungs, can the lead ballast be fastened to the "chassis" of the IDA, under the counterlung, instead of onto the lid, over the counterlung? If not, please give a the reason as I think that by doing this, the lid will be kept light and easy to operate, and the lead ballast will have minimum effect on reducing the counterlung volume, as the counterlung will always have a tendency to float away from the chassis, in effect then floating away from the lead ballast. 2) Under the curent scrubbers, and O2 cilinder, there is a lot of "dead space" where all types of interresting things can be placed and fixed, i.e battery canisters etc... Has anybody thought of building / designing 2 x bigger (longer) scrubbers that will lie in the place where the current "small" metalic scrubbers lie, but extended so that the scrubber length totally fills the "dead space" under the current scrubbers. By rough calculation I estimate it will almost give you a "third" scrubber (volume wise) which will deffinately extend bottom time and possibly even depth with the IDA-71, as the total scrubber size will then almost be equal to the IDA-72 giant scrubber. To build a axial scrubber with thread to lock and screw into the place where the current scrubbers screw into, cannot be that difficult. How much would WOB be influenced by doing this? Your input and thought are appreciated Best regards Johan
(Offline)

26th December 2006, 07:39	#2 (permalink)
GKAM digital nomad Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: May 2005 Location: Greece Posts: 254	Re: IDA-71 Questions / Ideas... Hi Johan, The IDA 71 needs about 4kg mounted as high as possible to counterbalance the CL buoyancy. At first, I did copy Dave's suggestion and added the weight under the lid. However, it soon became apparent that the reduction in available space for the CL expansion caused a problem for me. Perhaps my hose routing was also to blame, but now I have moved the weights outside the unit. This has greatly improved things not only wrt the CL but has also made the core unit lighter and hence more easy to manage. The ideal placement for the weights is as high up on the harness. Right where Spock used to apply the Vulcan death grip On the scrubber issue, I simply would not mess with the Russian scrubbers. They are simple, robust and well engineered. Use one scrubber if you intend to go no deeper than +/- 50m or keep both if you intend to dive the unit deeper. The space you see right now in your unmodified unit will most likely be taken up by the time you finished your mod. I'm very happy with my unit and dive it very often. Easy to setup and maintain and fun to dive. The only drawback is the lack of watertrap. Good luck in your mods! /GKAM __________________ Stay #
(Online)

26th December 2006, 12:20	#3 (permalink)
mverick ScubaPimp Current Rebreather/s: Megalodon Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Aug 2005 Posts: 557	Re: IDA-71 Questions / Ideas... For a 72 scrubber. Just start with a 72. On the 71, I'd use both scrubbers. Always. Not needed. But good if you start working hard. And sorb is cheaper then a pine box. I mounted my weights on top of box outside with zip ties.
(Offline)

26th December 2006, 22:34	#4 (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: 2,913	Re: IDA-71 Questions / Ideas... For the lead, simply tie it to the lid. Use plastic wire-ties to hold the weights to the "gill slots" on the lid over the counterlung. The counterlung will be flexed against the lead, does not affect it at all, and the rig when the lid is removed is easier to handle than if the lead is in the chassis. There shoud be NO impact on the effective counterlung volume. I have also seen divers place 2kg weights right on the shoulder harnesses, as close to the rig as possible. I do this on my Mark-15, actually. Don't reinvent the wheel with the scrubbers. Leave them alone. Use them as they are, and forget them. The Russians made them "just right". I also suggest using both scrubbr and carrying all diluent as a small stage bottle, fed to the unit thru a quick connect. Makes life easy, and you will want suit/wing/bailou gas carried as an offboard bottle anyhow. Why pretend to carry diluent internally when you are going to carry an external bottle in any event? Dave Sutton __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com Last edited by Dave Sutton : 26th December 2006 at 22:38.
(Offline)

27th December 2006, 06:18	#5 (permalink)
divingtoors RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Mar 2006 Location: Cape Town Posts: 103	Re: IDA-71 Questions / Ideas... Hi What I have done is as follows: I have put a 2L 200Bar cylinder for O2 in place of the supplied Russian O2 cylinder & valve. I have a KISS valve that will supply O2 to the counterlung Then I have taken 2 x 3L 200Bar Aluminium cylinders and fixed them to the chassis (offboard) with G-Clamps. The cylinders basically sit on the outside of the IDA-71 and looks almost like the rocket man The idea is to have the one 3L cylinder with diluent (offboard), and the other 3L cylinder as suit inflation / Wing inflation and 1st bailout (also offboard) (A regulator coupled to the suit inflation cylinder will be bungeed around my neck) I will then be able to run either one or two scrubbers with no problem or conversion at all. I plan to make a dummy scrubber from PVC piping to act as a "place keeper" for the removed scrubber, as i opted not to remove al the guts in the IDA, but only the "guts" where it affected the O2 cylinder. It looks great and works very well too, still keeping some of the original IDA-71 "flavour" My idea is to use Nitrox 32-50 depending on my maximum depth, as suit inflation. This will then double as a convenient..I call it a primary bailout, (for sanity breaths ) before switching to the main bailout (which will be clipped to the harnass) in the event that it will be needed. The unit is a bit heavy on land, but will be tested in water soon to see the net result. I am currently working on the PPO2 metering. I would like to know where the optimum placing of the P-connectors would be, as I intend to run a 2/3 sensor display and then later on an integrated VR3/HS Explorer. This means that the male P-connector will be quite long and I dont think the IDA CL is deep enough to accomodate a 2/3-sensor P-connector Any ideas and views that can assist? Regards Johan
(Offline)

27th December 2006, 14:35	#6 (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: 2,913	Re: IDA-71 Questions / Ideas... You don't need to make a dummy scrubber, you can simply plug the unused counterlung ports with plugs from McMaster-Carr. These are the rubber plugs with the flip-over lever to exand, used in the back of a small boat to let water out. You can imagine it. hey work just perfectly. I get them at the hardware store, with brass or stainless metal. Put the P-Connector on the SIDE of the counterlung, divers right shoulder. This way a long cell-probe does not "tent pole" the counterlung. I make also a folding cell probe to allow the cells to lay flat inside the lung, but a solid probe is easier to make and the P Connector on the side of the lung is fine. I think you have too much stuff attached to the chassis. I would remove the two "mounted" diluent cylinders and replace them with one cylinder carried as a stage bottle and connected thru a quick disconnect line to the rig. This way you can carry any size cylinder for the desired dive, and the rig itself is easier to carry. Unsnap the external bottle when climbing a ladder and hang it on an equipment line. Trust me, this will work a lot better and you will not even know it is there. Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
(Offline)

27th December 2006, 15:10	#7 (permalink)
zepp "Dyson with Death" daddy Current Rebreather/s: Classic Kiss Other CCR Home Build Other Rebreather/s: Not Bought Yet Other CCR Home Build Join Date: Sep 2005 Location: midlands Posts: 284	Re: IDA-71 Questions / Ideas... I have weights cable tied to the outside and use a three cell holder which plugs into a p port made by John Routley AKA Narked at ninety. __________________ I'm not a bad person.....HONEST my homebuild photos http://www.rebreatherworld.com/photo...ery.php/cat/48 CLASSIC KISS #052/shearwater The Dyson is back
(Offline)

27th December 2006, 17:10	#8 (permalink)
mverick ScubaPimp Current Rebreather/s: Megalodon Other CCR Home Build Other Rebreather/s: Other CCR Home Build Join Date: Aug 2005 Posts: 557	Re: IDA-71 Questions / Ideas... I use 2 cells, one for a po2 meter. Single read and one for a VR3 or HSE. But the HSE hasn't ever worked. And I'm not happy with the VR3's alog. If you do a dil flush and one or the other isn't jiving with the dil flush. Guess what, read the other. I believe in 3 cells for voting logic. But for mental logic I stick with 2. I'd side sling a al40 and route it with a quick connect to the unit for your dil. Then you have a good sized bailout enough for your wing and suit and you also don't have a rig as wide as a elephant. LOL But, do as you like. They are toy's and your way will work fine.
(Offline)

30th December 2007, 18:01	#9 (permalink)
teomannaskali RBW Member Current Rebreather/s: Home Build Other Rebreather/s: Not Bought Yet Home Build Join Date: Feb 2006 Location: Istanbul TR Posts: 421	Re: IDA-71 Questions / Ideas... Has anyone ever cut open an ida cannister? I would really like to see the inside. Teoman
(Offline)

30th December 2007, 18:44	#10 (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: 2,913	Re: IDA-71 Questions / Ideas... Quote: (Originally Posted by zepp) I have weights cable tied to the outside and use a three cell holder which plugs into a p port made by John Routley AKA Narked at ninety. Cable tie them inside... you'll never know the difference and it'll look far better. Another user of a properly designed sensor holder... the ever-popular DS-3. Wonder where that part number came from..... Dave __________________ "Silent Diving with No Bubbles and No Politics".... www.nobubblediving.com
(Offline)

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