Mk25 Scubapro

[Belce]

Thank you for your replies, they are all apperciated.

It is not just my own and those that I know use this that I put forward as evidence.

1. The US Navy has the Mk25 with the S600 on its approved equipment list for diving to 38 F and 190'
2. This first stage passes a test of successfully operating at 2C and a tank pressure of 4300 PSI

Is the Mk25 something I would choose to use under the ice at Antartica? no, but diving the regulator well within its tested limits is something that I can recommend. I also think that people here on this forum should be able to recommend as well.

So sorry it is not just my experience here that informs my argument, but documented testing by experts I know we trust already.

Cheers

 

[James Bond boat entry]

The US Navy's approved use list.

http://www.supsalv.org/pdf/ANUView.pdf

 

[awest513]

Does anyone have any expierence with the newest scubapro Mk25/700 regulator set I'm in the market and this looks like top of the line equiptment, any comments welcome, thanks

 

[Speardoggin]

Does anyone have any expierence with the newest scubapro Mk25/700 regulator set I'm in the market and this looks like top of the line equiptment, any comments welcome, thanks

I just bought it so I will post my impressions as compared to my Aqualung Legend and mares Abyss mr42.

 

[akscubaduck1]

BTW, the US Coast Guard, US Navy and NOAA have selected the Oceanic Delta 4/FDX10 as their cold water regulator of choice. They did the joint selection process after the Coast Guard lost a couple of divers in cold water. No, I don't know what regulator they were using. But I know what they are using now!

Richard

After reading the accident report, The deaths had nothing to do with what gear they were using(other then to much weight). Lack of topside support and training seemed to be the problem.
Both divers were on training dives.
I don't know what regulators they were using ether
I love the coasties (don't get me wrong) but they had some big issues that day.

 

[Belce]

I use the A700/Mk25 combo and have been using it since June when it first came available here in Canada. It has been great and flawless. The Mk25 1st stage has a nice shiny chrome coat but does perfect out here just like all the other Mk25's that I have encountered. Paired with the A700, I would say it is easier to breathe at 100' with this regulator that it is to breathe normally at sea level, of course without a regulator.

My personal experience with regulators is limited to rental Mk2's with R295's and my current setup of the A700/Mk25. While I have breathed on other setups they are not enough for me to express an opinion here.

If you look at my avatar's photo you will see the A700 in my mouth and should be able to agree that is a Mk25 on the tank.

In the 70's I took a skin diving class as kid. At the end of it my instructor took us individually on a length of the pool with scuba gear and I very much remember the experience. It was a 2 stage system and when you inhaled it felt like there was a push behind your intake. Today when I take breathe on my A700/Mk25 setup I don't feel that intake push that I recall from then, I don't ever have any challenge breathing ever, since I started using this I have added 10 minutes to my dive times on an 80 cubic foot tank. Alot of that I think is due to the move from rental gear to my gear and becoming more comfortable in the water, but I think the better gear has helped some.

 

[DA Aquamaster]

I switched from Mk 25's to Mk 17's when my diving was predominantly in alpine lakes with bottom temps in the 35-39 degree range below 100'. In my experience, the Mk 25 requires very good cold water technique in temps below about 45 degrees, and in particular at depths below 100' where flow rates are higher or the potential for a freeze flow tends to rise dramatically.

I personally never had a freeze flow, but I also used 2400 psi tanks and very good cold water techique. I have however been in the water with numerous divers who experienced freezeflows in temps below 45 degrees and at depths below 100', and this was even more common with divers in positive pressure full face masks where a less than perfect face seal may create a constant flow and resulting cooling load on the reg.

In short, some people have exellent luck with the Mk 25 in what ever they define as "cold" water, while other people do not. Given that I was doing deep decompression diving in very cold water, it made sense for me to switch to the fully sealed Mk 17 as in testing it has tolerated extremely high flow rates at 165' in 35 degree water for 200 minutes without freeflowing. Navy listed or not, the Mk 25 simply cannot pass that same test.

Before the Mk 25 I used the Mk 20 and preferred it as I could fit it with the late style Mk 15 boot and fill the ambient chamber with either silicone or Christolube to prevent water from entering the ambient chamber. This again creates a virtually bullet proof cold water first stage.

Scubapro went away from their SPEC (Silicone Protected Environmental Chamber) system when they moved to Christolube back in the day when O2 cleaning was considered essential for any ntrox mix. In part it was done to ensure the reg stayed O2 clean and in part it was done to prevent cross contamination of O2 clean regs from silicone on the service bench and tools. SP could have opted to retain the SPEC system using Christolube (a CPEC system?) but for what efver reason elected not to and relied in stead on the TIS system - which continued to be tweaked for years on the Mk 25 in an effort to get a sufficient degree of very cold water reliability.

Personally, I just don't think it makes sense to go with a first stage with a known history of cold water failure when a much better cold water first stage is available. Currently I dive a lot less in cold water and if I do the depths tend to be shallower. But I still prefer the Mk 17 as much of my diving is now in caves where silt, sand and restrictions are common place and where the Mk 17 does a much better job at staying clean internally than any of the various SP piston first stages I have used on deco and stage bottles.

 

[Belce]

Thank you DA

 

[drdaddy]

What is "good cold water technique" and where can I read about it?

I have also never had a free flow, but I've only had about 10 dives where I'm diving around 40 degrees farenheit (Clear Lake - high altitude). I have an older Sherwood Oasis - I love it!

 

[Speardoggin]

Why not consider the Aqualung Legend Glacia? It breathes absolutely amazing at all depths and has all the cold water features. It would suck if you decided to dive and the water temps go below what the MK25 can handle. I have breathed out of the a700/MK25, legend Glacia, Legend ACD, and Mares Abyss 42 at depths up to 160 fsw. I would say the A700/MK25, glacia and regular legend all breathe amazing at that depth and you will not tell the difference. If anything, I believe the aqualung regs have slightly easier breathing. I know if I was going into deep cold water, I wouldn't risk it. why take a chance with your life just because?