For Sale Scubapro Mk 3

[Kupu]

I agree it is likely MK3. The MK2 piston head is about the size of a quarter and the MK3 piston head is about the size of a nickel.
A correction to my earlier comment about the MK5 showing up a couple years after the MK1, it actually showed up 1 year later in 1965.

 

[Tracy]

MK 3

My bad. So now what you really need is a mk3.

 

[Tracy]

I agree it is likely MK3. The MK2 piston head is about the size of a quarter and the MK3 piston head is about the size of a nickel.
A correction to my earlier comment about the MK5 showing up a couple years after the MK1, it actually showed up 1 year later in 1965.

I have a few different mk2 of various generations. Sounds like this is a MK3. The piston is noticeably smaller than a mk2.
Thank you

 

[Eric Sedletzky]

My bad. So now what you really need is a mk3.

I’ll tell you a quick story about a MK3/108 I had.

I have a friend who had this incredibly ugly green corroded MK3/108 hanging up on a wall in his man/dive cave. He was actually a world champion competitive freediver spear fisherman and scuba was just an accessory to him, he didn’t really care about scuba unless it was lobster season in Socal.

In 1970 he wanted to enter a spearfishing competition somewhere on the other side of the world but the rules stated that contestants needed to be scuba certified. So he contacted a NAUI instructor buddy of his and he got a one day course complete with one ocean dive. The instructor even threw in this used MK3/108 reg with no SPG. They used J valves then or waited for it to start breathing hard then came up.
So one day in the 1980’s he’s using that reg on a single 130 tank diving to 200’ in Florida looking to shoot a grouper. No grouper, but he did end up getting bent when he ran out of air coming up to 60’. He did a blow and go (ESA) and his shoulder ended up inflating and he could hear crackling sounds. To this day five surgeries on that shoulder from getting bent!
Anyway, from that point on he hung that reg up on the peg not even rinsed, he was done with it and scuba.
He also mentioned that he “might” have had it serviced once in the 18 years he used it but couldn’t remember when.

Then he gave it to me.
I tore it down, soaked it, stripped all the almost gone chrome off and polished out the brass both on the first and second stage. It was a one of a kind gold colored MK3/108 when I was done.
I put a kit in it and it worked like nothing ever happened.
So if anybody is wondering about the durability of a MK3, this about spells it out that it is the most indestructible reg ever made!
Just not fancy.

 

[Tracy]

I’ll tell you a quick story about a MK3/108 I had.

I have a friend who had this incredibly ugly green corroded MK3/108 hanging up on a wall in his man/dive cave. He was actually a world champion competitive freediver spear fisherman and scuba was just an accessory to him, he didn’t really care about scuba unless it was lobster season in Socal.

In 1970 he wanted to enter a spearfishing competition somewhere on the other side of the world but the rules stated that contestants needed to be scuba certified. So he contacted a NAUI instructor buddy of his and he got a one day course complete with one ocean dive. The instructor even threw in this used MK3/108 reg with no SPG. They used J valves then or waited for it to start breathing hard then came up.
So one day in the 1980’s he’s using that reg on a single 130 tank diving to 200’ in Florida looking to shoot a grouper. No grouper, but he did end up getting bent when he ran out of air coming up to 60’. He did a blow and go (ESA) and his shoulder ended up inflating and he could hear crackling sounds. To this day five surgeries on that shoulder from getting bent!
Anyway, from that point on he hung that reg up on the peg not even rinsed, he was done with it and scuba.
He also mentioned that he “might” have had it serviced once in the 18 years he used it but couldn’t remember when.

Then he gave it to me.
I tore it down, soaked it, stripped all the almost gone chrome off and polished out the brass both on the first and second stage. It was a one of a kind gold colored MK3/108 when I was done.
I put a kit in it and it worked like nothing ever happened.
So if anybody is wondering about the durability of a MK3, this about spells it out that it is the most indestructible reg ever made!
Just not fancy.

I read that as "If you throw in a 108, I would definitely like to purchase this from you."

Does that sound correct?

 

[Angelo Farina]

MK I was the first balanced flow tru piston design sold by Scubapro, followed by the MK V a couple years later.

Thanks, I had missed any drawing of the MK1. This explains how the MK5 was born, adding a swivel turret to it.
The MK1 had a balanced piston, no rotating turret and just one LP port.
Here a photo I found on another sale offer here on SB:

 

[Angelo Farina]

I think it is.
Kinda weird how they went from MK1 to MK3 to MK2?
I would have thought 1-2-3

You find some detail on the succession of scubapro first stages in this old thread:

"Scubapro Ad 1963"

Found this add in a copy of "Skin Diver Jan 1963, question was this second stage design ever marketed?? Be good to see proper fotos.

scubaboard.com

In practice, Scubapro started operation in 1963 with two first stages, MK1 and MK2.
Mk1 was a balanced piston design, but not flow-through. It was a crap design, with many problems, so Scubapro retired it very shortly, and they even attempted to "buy back" all the units sold. I have no photo, nor drawing of this early Mk1, which Scubapro attempted to "cancel" from their history.
So in the official lineup, Scubapro started with the Mk2 only in 1963. The year later they added the cheaper version Mk3, and and in 1964 the "new" Mk1 (aka Mk1-v2), the first truly balanced piston with flow-through, as shown in the previous photo.
So in 1964 there were Mk1, Mk2 and Mk3, in decreasing order in terms of performances.
In 1965 the Mk5 was launched, an improvement of the Mk1-v2 with added swivel turret and two LP ports.
Later on Scubapro released Mk6, a Mk5 with pneumatic joke (another crap design), then Mk7 (the "honker", with audible warning of low pressure).
Finally Mk8 (a Mk5 without swivel, but with top and side LP ports), which was the last of first-gen Scubapro regs.
The newer generation with smaller piston entirely contained in a single piece of brass started with Mk9 and Mk10, the first without swivel turret and the second with swivel turret.

 

[Kupu]

Mk1 was a balanced piston design, but not flow-through. It was a crap design, with many problems, so Scubapro retired it very shortly, and they even attempted to "buy back" all the units sold.
In 1965 the Mk5 was launched, an improvement of the Mk1-v2 with added swivel turret and two LP ports.
Finally Mk8 (a Mk5 with some sort of sealed chamber for cold water operation), which was the last of first-gen Scubapro regs.

Thanks for the information Angelo, and apologies to Tracy for going off topic - I enjoy these discussions on old SP regs perhaps a bit too much. Scroll down to the posts by ovallis on this VDH thread to see photos of some internal parts of the retired verion of the MK 1.

The 1965 catalog shows the first MK5 with a bottom port, possibly a single LP port although I have never seen one or found a description of this version.
The MK8 chamber was not sealed. About the same time as the MK8 was introduced, Scubapro did offer the first generation environmental kits as an option for the MK5 as shown in attached photo.

 

[Tracy]

Scubapro did offer the first generation enviromental kits as an option for the MK5 as shown in attached photo.

If you need one of those, I have a sealed mk5 listed as well. Comes with a nice Pilot.

 

[Angelo Farina]

If you need one of those, I have a sealed mk5 listed as well. Comes with a nice Pilot.

Nice! And sorry for derailing this thread with the history of early SP first stages.
After realising some inconsistencies in what I wrote, I went back consulting the extensive collection of SP catalogues available here:

CATALOGHI COMPLETI | BluTimeScubaHistory

Looking at the catalogues in the period 1963-1980, we can see that originally in 1963 Scubapro was selling just two regs, both balanced, one is the (in)famous "J" model 7101 incorporating a mechanical reserve, the other is the "standard" model 7100, shown here:

This strange reg is already "balanced", as the text clearly explains, so it is basically the predecessor of Scubapro MK I.

The year later, 1964, we find already the three decreasing-quality regs:
mod. 7100 - Mark I - balanced
Mod. 7105 - Mark II - unbalanced
Mod. 7104 - Mark III - unbalanced, cheaper
They are shown here below in the same order:

In 1965, these 3 levels are unchanged, but a 4th level, even higher performances reg is added, model 7106 - the Mark V, shown here:

Please note that in this early version of the Mark V there is no rotating turret and there is only one, on-axis LP port.
No catalog is available for 1966, unfortunately.
In 1967 we find again the same 4 regs, ordered in decreasing performances as:
- mod. 105 - Mark V
- mod. 101 - Mark I (v2)
- mod. 102 - Mark II
- mod. 103 - Mark III
Whilst Mark II, III are unchanged, Mark I is now the new model, resembling closely the previous no-swivel Mark V of 1965, but more rounded, and is shown here:

The Mark V, on the other side, is now the commonly known version, with swivel turret and 2 LP ports, as shown here:

Back on topic: the Scubapro MK III is found also in subsequent versions of the SP catalogue, until 1980. The MK III is still present in the 1980 catalog,, so it was produced in years 1964-1980 (I do not have access to catalogues after 1980, so perhaps it remained in production further).
The MK I, instead, also remained in US version of the SP catalogue until 1978, for reappearing in 1980 re-marked as MK VIII. You can see it here:

The MK I-v2 (flow-through, lately renamed MK VIII) is a nice 1st stage, which can be used even today, instead the original MK1 was the one with severe problems, which Scubapro retired.

I apologize for the long post, and I hope to have clarified the glorious history of those early SP first stages, of which only the MK II survives as of today.