Calling all SP MKV owners

[John C. Ratliff]

Interesting story. But I have a Mk5 with 4 LP ports (none on the end). Where did that version come in?

I think that this one was between the other two I mentioned above, but before the U.S. Navy test reports came out. The additional LP ports were added as people went to BC inflators, so that they would have options without having to use an adaptor.

You may inquire of some of the Scubapro dealers, and see if they may have a spare cap that would fit your regulator with the top port in addition to the other four ports. If you can find it, this will improve the Mark V's performance in really demanding situations. What it does is to minimize the flow turbulence within the cap section of the first stage, and allow almost laminar air flow into the LP hose.

Realize that this only helps on dives where air demand is extremely heavy, and/or deep. There are probably many divers, even tech divers, who don't realize the advantage of putting their primary second stage on that top LP outlet too. Basically, any time you put a 90 degree direction change in a flow of air, you will experience turbulance and a decrease in effeciency of the regulator.

One of my industrial hygiene books describes it in a ventilation system as

...any time the flow changes direction (such as at a turn or elbow) or undergeos a sudden change in the duct size that causes drastic velocity changes, the violent air mixing and eddy sformation also give rise to system energy losses. That is to say, if elbows, expansions, contractions., etc., exist between points B and C..., the shock losses occurring in these fittings will conusme static pressure over and above that lost to duct friction. These losses, like all such sources of energy loss, must be quantified in terms ofstatic pressure and added to the overall energy requirements...*

This would apply to systems under pressure too, but their calculations for static pressure loss (typically using loss coefficient of 1.2). So some factor of the static pressure must be added to get the same flow, or the flow will decrease due to the "violent and turbulent mixing that would occur at an elbow or transition."*
*DeNardi, Salvatore R., The Occupational Enviroment,Its Evaluation and Control, American Industrial Hygiene Association, AIHA Press, 1997, page 896.

SeaRat

 

[Wayward Son]

Quite a bit of history documented here:

http://www.scubacollector.de/html/scubapro2.html

Mk5 here:

http://www.scubacollector.de/html/mk_51.html

 

[John C. Ratliff]

I dove my Mark V/A.I.R. I combination on Saturday, and had a wonderful dive. That regulator is really a performer. It does breath a bit wet in some positions, but that's a function of having the exhaust valve also the main diaphragm, and its orientation to the regulator. But I love its performance.

SeaRat

 

[undrwater]

I just picked up 2 vintage regulators. I believe both are Mark V's but different iterations.

Here's a link to one of them:
http://dwigtek.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=148&g2_serialNumber=1

Anyone know which this is?

The other has a "T" at the first stage for 3 LP ports. I haven't seen that in any of the photos yet. I'll put it up here soon.

 

[Berdman]

I have a mk15 but will be selling it cuz the dive shops tell me its 20 years old theres alot better stuff out now.......I never used it i might add....

 

[Wayward Son]

I just picked up 2 vintage regulators. I believe both are Mark V's but different iterations.

Here's a link to one of them:
http://dwigtek.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=148&g2_serialNumber=1

Anyone know which this is?

The other has a "T" at the first stage for 3 LP ports. I haven't seen that in any of the photos yet. I'll put it up here soon.

That is a Mk5 similaor or identical to mine. It clearly has 4 LP ports on the turret & 1 HP port. If it has a 2nd HP port on the opposite side of the body & a 3000 psi yoke, it's the same as mine.

 

[halocline]

I have a mk15 but will be selling it cuz the dive shops tell me its 20 years old theres alot better stuff out now.......I never used it i might add....

Ummm...and you believe them? You ought to send it off to get rebuilt and try it first. I have a MK15 and it's great. It's doubtful in my mind that you could buy a better breathing 1st stage, although if you're in sub 40o water, you might want a sealed 1st stage. What 2nd stage do you have with it?

 

[undrwater]

That is a Mk5 similaor or identical to mine. It clearly has 4 LP ports on the turret & 1 HP port. If it has a 2nd HP port on the opposite side of the body & a 3000 psi yoke, it's the same as mine.

No...just one HP port. Should it be marked somewhere to indicate that it's a 3K yoke? I suppose it might have difficulty with the 3442 tanks? I breathed the other one in the pool, and it was as easy (if not as smooth) to breathe as my ATX50. Would there be an issue if I were to connect it to the Apeks 1st? I'm considering replacing the '95 Oceanic Alpha with it (after service, of course).

 

[Wayward Son]

The old yokes were 2400 psi rated. Later, after 3000 psi AL80 tanks became more widely used, the yokes became heavier & rated for 300psi use. They have 3000 stamped across the base of the yoke, on one side, not both.

Using an older one on 300psi tanks it'll hold for a while, but eventually the threads will strip out. You can upgrade it to a 3000 yoke simply by obtaining one & having it installed. I don't think you can buy a new yoke for it any more, but often older regs get scavenged for parts so it shouldn't be too tough to find one.

These yokes may not fit on the new 3442 valves. Not sure, i haven't tried it, but the 3442 valves on Faber tanks is much thicker than a normal yoke valve.

 

[undrwater]

Thanks Wayward Son for the info! Neither of the regs are marked with the 3k PSI, so I suppose I'll use them for the LP tanks I got them with.

Here's a link to a pic of the other reg. Notice the "T" at the cap(?).
http://dwigtek.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=166&g2_serialNumber=1

I look forward to getting at least one of these guys serviced...do you have any opinion as to which is the better first stage? (I'm guessing these seconds are the same)