Sea Hornet Air Commando Regulators

[Fibonacci]

Recently acquired an ex-Royal Australian Navy (RAN) stamped Sea Hornet 'B-Commander' which was the last refinement of the Command Air regs... as was used by our RAN clearance divers and Special Forces.
Note the lightweight plastic LP seat carrier and revised Turbo Boost shroud which gave a less directional pulse of air when fully open, vs the Command Air.

It came with a spare near-new Mk 5 DIN first stage, which was just as well... the IP was all over the place, partly because the HP seat had collapsed!
On more detailed checking, the first stage had obviously been connected to an oxygen rich cylinder and ignited lubricant inside... all black with eroded gas jetting channels.
30% of the brass around the HP seat support collar had just disappeared, with one edge of the HP seat extruding into the void

 

[Fibonacci]

I'll try and get the damaged one sectioned through the HP seat area so you can see the effect of oxygen igniting lubricant inside a non-O2 cleaned reg!

 

[Fibonacci]

Kim Preece was granted two US Patents on his Sea Hornet Command Air regulator designs US5437268 granted August 1 1995 and US5735269 granted April 7 1998...

So my hunch was correct, these regs were designed in Australia by TD Preece then the IP was subsequently sold to ProSub with sad demise of Sea Hornet.

Both relate to the innovative concentric sleeve and venturi assist baffle.

https://patentimages.storage.googleapis.com/19/7f/a9/594866327acd16/US5437268.pdf
https://patentimages.storage.googleapis.com/6b/fe/c4/302aef802bf9cd/US5735269.pdf

 

[reefrat]

I used to occasionally see new Sea Hornet Commander regs for sale in my LDS in Perth Western Australia when I lived there in the early 1990’s. Always thought they looked great, very well finished and thought out. But I didn’t buy one because the shop was pushing a major brand and I went that way instead.

 

[Fibonacci]

Just picked up a Sea Hornet MK 1 reg set, in the process of overhauling it.

For students of regulator design, the MK1 was a balanced piston design that featured an innovative external IP adjustment system using three pins to transmit force to the base of the spring. No shims needed!

While a good idea in theory (allowed ~1 BAR or 14psi additional IP if fully screwed in to the hard stop) if the spring sagged over time the pin travel was insufficient to get IP up to the recommended 10 BAR (145psi). It was also difficult to flush out the sea water which tended to collect in the pin recesses leading to accelerated corrosion over time.

The MK 5 featured more conventional adjustment shims

 

[abnfrog]

they are prosub and it was first

 

[Fibonacci]

they are prosub and it was first

See my earlier post about this:

Kim Preece was granted two US Patents on his Sea Hornet Command Air regulator designs US5437268 granted August 1 1995 and US5735269 granted April 7 1998...
So my hunch was correct, these regs were designed in Australia by TD Preece then the IP was subsequently sold to ProSub with sad demise of Sea Hornet.​

I met with Peter Katz at OZTek recently who was Sea Hornet's design chief, responsible for R&D on their regulator and speargun lines. Not sure if they lodged patents for other designs, but they certainly did for the Command Air second stage.

 

[abnfrog]

good to know .......now I do too

 

[Ghetto Diver]

Hmmm...Beuchat used tbe 3 pin system as well. I have a VS4 with this.

 

[Fibonacci]

A quick search in both the Australian and US Patent registers does not bring up any first stage designs, so the jury is out on this one.
However, like Ted Eldred's Porpoise regulator, it may never have been patented... a very expensive process for a small Australian manufacturer primarily catering to a local market.
I will see what else I can find via my HDS contacts...

This is what I can find on the IP Australia Website
IP Australia

Preece T. D. & Co. Pty Ltd
1989904577 1989-06-06
Provisional
Status: Lapsed
Improvements in diving regulator demand valve

T.D. Preece & Co. Pty Limited
1997909737 1997-10-09
Provisional
Status: Lapsed
Signalling device

T.D. Preece & Co. Pty Limited
1998905993 1998-09-17
Provisional
Status: Lapsed
Signalling device

Preece, Kim
1990057350
Paid to 2006-06-06
Status Ceased
Diving regulator demand valve

Preece, Kim
1993035525
Paid to 2006-06-06
Status Ceased
Improvements in diving regulator demand valve

Preece, J.D.
2015904905 2015-11-26
Provisional
Status: Lapsed
Speargun Assembly