Mares Rebel 2 in cold water

[sermar]

Do I need to have the cold water kit to dive at 40-50F with the Rebel 2?
I am waiting to receive the ordered Abyss 42 and I would like to use the Rebel 2 in the meantime.
Thanks,
Sergio

 

[Greg Barlow]

The R2 Rebel does not have a cold water kit available for it. The first stage is an unbalanced piston design that is open to the ambient water. It is super reliable, and only has one moving part.

The first stage does not have the gas flow capability of the balanced diaphragm models from Mares, but that also makes it unlikely to ice over from diving in water temps around 50 degrees or warmer. I would hesitate to use it in the 40 degrees range. The unsealed balanced piston regs on the market are more likely to ice over due to their greatly increased gas flow capabilities.

If you are making recreational dives in water no colder than 50 degrees, then an unbalanced piston first stage is a very good choice. Models like the Mares R2 Rebel are used by many dive centers as rental regs. Dive buddies and I have used them for deco and stage cylinders while making technical dives.

Greg Barlow

 

[sermar]

Greg,
Thank you for your response.
In the Mares website, for what I understood, there is the CWD Kit and CWD Dry Kit.
The CWD Kit is for the Proton 12 and the Rebel 12 and 2, while the CWD Dry Kit is for the Proton 42.
In any case I am going to follow your suggestion.

Could you please let me know as well for the second stage. I have also a Rebel Octo than will be attached to the Abyss 42.

Thanks again,
Sergio

 

[Greg Barlow]

Greg,
Thank you for your response.
In the Mares website, for what I understood, there is the CWD Kit and CWD Dry Kit.
The CWD Kit is for the Proton 12 and the Rebel 12 and 2, while the CWD Dry Kit is for the Proton 42.
In any case I am going to follow your suggestion.

Could you please let me know as well for the second stage. I have also a Rebel Octo than will be attached to the Abyss 42.

Thanks again,
Sergio

Sergio,

I looked at the website, and read the same information that you did. I believe that Mares used the same information for the R2 that they used for the MR12. I have serviced Mares regulators for a number of years, and have never received any information regarding a CWD kit for the piston model. I also just now looked through my 2008 service materials, and can find nothing listed for the R2. Such a system wouuld require the ambient water chamber to be filled with either silicone or an oxygen compatible lubricant, and then to have a sealing cap over the area with the holes. The body is not milled to hold such a sealing cap, so I can say with 99% certainty that it isn't available.

My guess is that the individual working on the site didn't catch the error. The silicone oil CWD kit is used for all the diaprhram regs other than the V42 model. It uses a dry sealed system utilizing a piston.

The Rebel octo is a very basic polymer bodied second stage. It is fine as an octo, or for use on recreational dives. It is not designed for water colder than 50 degrees due to the fact that the case material doesn't transfer heat from the water very well. Mares metal bodied second stages are much better in this regard. I made a number of dives this winter in water as cold as 34 degrees with my V42 Proton Metal reg, and it worked perfectly. That said, I have the original version of the Rebel design that was known as the Axis. It has been used on many technical dives as a deco cylinder reg, and has been very reliable.

I do recommend removing the hose protector from the second stage on the Rebel. This allows water to flow around the hose fitting area and does aid somewhat with using the surrounding water's heat to warm the incoming gas up a bit. Remember, no matter how cold the water, it is still considerably warmer than the gas flowing through the hose.


Greg

 

[sermar]

Greg,

Thanks again for the explanation.

I think that Mares are great products; I have been using Mares products for long time in dives in the warm Mediterranean Sea.
The only complain I have is with the information in their manual and website are not complete and comprehensible and in this case exact as they should.

I purchased a Zeagle ZX-50D waiting for the Abyss42 (which I can wait to try and compare with the Zeagle).
I will dive mostly in cold water and at this point it is necessary to have another high performance regulator.
With the information from the Zeagle website was easy to understand that the ZX-50D is ideal for cold water dives due to the dry environment of the diaphragm 1st stage and the heat exchanger in the second stage.

From the information I gathered from the Mares website for the Abyss 42, the first stage (MR42) is not dry sealed but the hight thermal conductivity of metal, "limits the freezing effect".
This is unless the CWD Dry Kit is installed as reported in the manual that warn for diving below 50F.

There is not a specific manual available online for the Abyss 42; it refers only to the MR22 first stage and the CWD Kit, therefore I presume that is valid for the MR42 and the CWD Dry Kit.

Did you install the CWD Dry Kit in your V42 Proton Metal for you cold water dives?

Sergio

 

[Greg Barlow]

Sergio,

None of my Mares regs have the CWD kit installed, and all of them are regularly used in water temperatures below 50 degrees. In fact, most of my Mares regs have been used in water in the low 30s over the years.

One of my close friends is an ice diving instructor, and he has never had an Abyss experience icing conditions while ice diving. He also uses V16 Proton regs for ice diving, and none of his regs are using the CWD kits.

I am a big fan of the metal second stages that Mares produces. My favorite is the Proton Metal, as it is very easy to tune due to the side port. Now that the new Abyss uses the same access port, it will be even easier to finely adjust.

When diving in cold water, proper technique is at least as important as reg choice. You should never exhale into a regulator while at the surface if the air temps are near or below freezing. You should also try to avoid long bursts on inflator hoses, especially while inhaling. I also set my first stages to have an intermediate pressure of 138psi (+-3) while diving in cold water.

There are some excellent articles on diving in cold water on the website of the British dive mag "DIVER". Their website is Divernet - Diver Magazine Online | SCUBA | Diving | Dive Shows | Gear Tests | Travel | News

Greg

 

[sermar]

Greg,
I agree that learning ice diving technics are more important than the selection of the reg.
I am a big fan of metal second stages from Mares as well. One of my first regulator back in the late '80 was the Mares MR12 III and it is still working.
Thanks for your great help and suggestion.
Sergio

 

[Greg Barlow]

I was more than happy to help. I own a couple of Mares MR12 III regs myself. I collect and restore the original Voit Swimaster MR12 regs. They are my favorite vintage single hose models. My favorite double hose reg is the Voit 50 Fathom.

Greg Barlow

 

[diveKi]

I know this is an old thread, but I think it is rather useful to add my question here than to spread the information in multiple threads.

I purchased a Voltrex 2nd which came with a M12 first. The M12 has an CWD installed and has an IP of 8.6 bars.

Since all my other Mares firsts are set to an IP of 10 bars, I would like to match the MR12 to them, so I keep my firsts and seconds interchangeable.

I found a neat tool for disassembling the CWD online, so that I can reach the adjust nut. Unfortunately the shipping from the US to Europe costs 2 times as much as a CWD new old stock, which includes Mares‘ (dis)assembly tool already.

So my question is, if the CWDs which are made specially for the MR12, MR22, V16 or MR32 respectively are interchangeable inbetween?

Otherwise you mentioned a lower IP of 138 psi +-3 for cold water diving. Is it recommended to lower the IP for Ice diving? I think I saw the same statement in the Mares service manual when installing the CWD, but thought it would be a typo.

If so, do I have to adjust the 2nd to this lower IP? Or do I match them to 10 bars (148 psi or so, I guess)?

Thank you

 

[lowwall]

I know this is an old thread, but I think it is rather useful to add my question here than to spread the information in multiple threads.

I purchased a Voltrex 2nd which came with a M12 first. The M12 has an CWD installed and has an IP of 8.6 bars.

Since all my other Mares firsts are set to an IP of 10 bars, I would like to match the MR12 to them, so I keep my firsts and seconds interchangeable.

I found a neat tool for disassembling the CWD online, so that I can reach the adjust nut. Unfortunately the shipping from the US to Europe costs 2 times as much as a CWD new old stock, which includes Mares‘ (dis)assembly tool already.

So my question is, if the CWDs which are made specially for the MR12, MR22, V16 or MR32 respectively are interchangeable inbetween?

Otherwise you mentioned a lower IP of 138 psi +-3 for cold water diving. Is it recommended to lower the IP for Ice diving? I think I saw the same statement in the Mares service manual when installing the CWD, but thought it would be a typo.

If so, do I have to adjust the 2nd to this lower IP? Or do I match them to 10 bars (148 psi or so, I guess)?

Thank you

It's always nice to revisit old Greg Barlow posts.

Mares published Technical Bulletin 30 in 2017 which overruled their previous recommendation to lower the IP when using a coldwater kit except for the Navy II Abyss (because a change to the Navy would require recertification by the Department of Defense). I'll attach it here. Note that the only version of the Tech Bulletin I could find was in Japanese, so I'm including the original and a version run through Google Translate.