Question Has anybody dived with the RD1 rebreather and if so how was experience?

[DontheDiver]

Question:
Has anybody dived with the RD1 rebreather and if so how was experience?

 

[lostsheep]

paging @Jona Silverstein

 

[Jona Silverstein]

ding dong

paging @Jona Silverstein

RD1 instructor here, The RD1 is a very capable unit in the various different configurations that are available. Which mode are you looking at the unit for? as an O2 rig or as a full mixed gas rig so I can better tune my responses for you. And what specifically would you like to know about it?

thanks

 

[DontheDiver]

Hello Jona,
Thank you for your quick reply. My interest in the RD1 is for O2 operation at the moment.

I was wondering about the breathing resistance in comparison to the Frog or Compact Oxy. I read an interesting paper by Mr. Lombardi in which he said this set could give a 5 hour duration which makes it very interesting.

Thank you for your assistance in this matter.

 

[Jona Silverstein]

While I have dived many units I have not dived the ones listed, but I can tell you this unit has some of the best breathing resistance of the ones that I have dived. Due to the loop configuration of the RD1 there is no sudden change of gas direction unlike a standard axial style rebreather. Water tolerance is incredible.

The unit as configured is labelled as a 5hr CCR based off the divers metabolic rate. what I can tell you is this can be pushed much further depending on workload.

Heres some of the scrubber data. "Over 3 test runs we average 173 minutes to 0.5% co2. This is under CE conditions of 1.6slpm co2 and 38 F temp with heavy breathing. This is also with a cheap fill of 2.3kg, rather than well packed (more like 2.6 kg)."

 

[DontheDiver]

While I have dived many units I have not dived the ones listed, but I can tell you this unit has some of the best breathing resistance of the ones that I have dived. Due to the loop configuration of the RD1 there is no sudden change of gas direction unlike a standard axial style rebreather. Water tolerance is incredible.

The unit as configured is labelled as a 5hr CCR based off the divers metabolic rate. what I can tell you is this can be pushed much further depending on workload.

Heres some of the scrubber data. "Over 3 test runs we average 173 minutes to 0.5% co2. This is under CE conditions of 1.6slpm co2 and 38 F temp with heavy breathing. This is also with a cheap fill of 2.3kg, rather than well packed (more like 2.6 kg)."

Thank you again. Did you find any difference in operational duration due to using different scrubbers?

The Frog is manufactured by Aqualung (Military Division) and the Compact Oxy was produced in Israel.

 

[Jona Silverstein]

Yes there will always be differences between different sorb types and grain sizes. 797 will always perform the longest under CE conditions due to the significant amount of CO2 production requirement but when reduced to a normal breathing rate most sorbs will perform the same.

Personally I like using the DragerSorb as it is a larger hemispherical grain thats about the size of 4-8 mesh. If offers lower breathing resistance than 797 because of the larger grain size.

 

[mr_v]

Yes there will always be differences between different sorb types and grain sizes. 797 will always perform the longest under CE conditions due to the significant amount of CO2 production requirement but when reduced to a normal breathing rate most sorbs will perform the same.

Personally I like using the DragerSorb as it is a larger hemispherical grain thats about the size of 4-8 mesh. If offers lower breathing resistance than 797 because of the larger grain size.

Where do you get yours? There is only one place I've found in the US - a medical supplier in CA.

 

[Jona Silverstein]

Where do you get yours? There is only one place I've found in the US - a medical supplier in CA.

AmronINTL

Draeger 6737818 DiveSorb® Pro Carbon Dioxide Absorbents 16.8 kg - 37 lb - ANU Approved

The Dräger DiveSorb® Pro was developed specifically for closed or semi-closed rebreathers in order to allow a high degree of CO2 absorption, and thus long dive times. ANU Approved Dräger DiveSorb® Pro Carbon Dioxide Absorbents 16.8 kg - 37 lb Canister 0099-LL-HOC-4490

www.amronintl.com

They almost always have it in stock, is cheaper than 797. and are 1 shipping zone away from me so they deliver almost as fast as amazon.

 

[OceanOpportunity]

The unit is engineered around a 5 hour dive capability.

-5.5 lbs sorb at about 1 hr/lb
-368 liters of o2 at 1lpm is 6 hrs, but assume shorter than 3000psi fills on oxygen
-maintain po2 1.0 for 5 hrs on your o2 clock

Configured like this, your o2 pressure gauge becomes a reliable means to gauge overall consumables. No more o2, no more diving.

We have a handful of photo/video pros using them in the shallows - really amazing in this application (no clutter on the chest), and very easy to turn into a mCCR for deeper stuff. RD1s have been dived >80m and no reason they can’t do more than that.