Sea Hornet Command Air regulators...

[Fibonacci]

OK as promised I am finally getting organised and posting some background info on the Sea Hornet Command Air range of regulators.

These were designed in Australia by Chief Engineer Peter Katz in the 1980's and were very popular here as being a very high performance regulator at an affordable price compared to imported offerings from US Divers, Scubapro, Spirotechnique etc.

All parts were manufactured in Sydney right into the 1990's... back the day before offshoring production to China became popular!

Sea Hornet was a huge manufacturer of all things underwater including a range of spearguns (since sold to AB Biller in the US) but their Command Air regulators are of primary interest to me. They were designed to crack reliably at 0.5"

Sea Hornet Command Air B Commander by Graeme Cameron, on Flickr

Sea Hornet Commander 1 by Graeme Cameron, on Flickr

Sea Hornet Commander 2 by Graeme Cameron, on Flickr

Command Air Ad 3 1996 by Graeme Cameron, on Flickr

Command Air Layout Drawing 1989 by Graeme Cameron, on Flickr

Unusually, they featured a distinctive removable clear panel so you could see the condition of the exhaust valve.

Reason?

In order to reach the design specification of reliable 0.5" cracking effort Peter Katz conducted many experiments on the case capacity, gas flow, lever geometry and the resilience of rubber components. While he stayed with silicone rubber for the diaphragms, natural gum rubber provided much faster recovery in breathing cycles. Think the snap of a latex speargun rubber.

Trouble was the natural rubber deteriorated rapidly esp in sunlight, so the clear window was introduced so the owner could readily gauge when to change the exhaust valve over.

The case is made from ABS plastic, with very thick walls... they were actually designed to withstand a full SCUBA tank falling over directly on top! I've seen video footage of a Command Air taking repeated hits without damage.

Command Air bottom detail by Graeme Cameron, on Flickr

Parts are long since unavailable since Sea Hornet's sad demise more than 20 years ago but they were designed to take standard AS568 o-rings and LP seats can be punched from 3mm silicone rubber... as were the originals!

The rotating Turbo Boost collar was very innovative at the time, and was patented by JD Preece (Sea Hornets owners) now off patent and much copied worldwide.

Command Air adjuster seat parts by Graeme Cameron, on Flickr

Command Air air barrel parts by Graeme Cameron, on Flickr

Sea Hornet Command Air ANSTI Test UK by Graeme Cameron, on Flickr

I'm a big fan of these regs and own several including a hybrid made from a USD Conshelf 21, and two Command Airs... primary on a Atomic Aquatics swivel hose. And yes, they really DO crack at 0.5" all day long

Sea Hornet Conshelf 21 reg set by Graeme Cameron, on Flickr

For general info, the o-rings required to service a Sea Hornet/ProSub Command Air second stage regulator are:

-010 (2 required)

-013

-015

-016​

All 70 Duro

[DavidRitchieWilson]

Some additional Sea Hornet publicity I chanced upon online over the years.

Sea Hornet speargun in 1960 Smith Sports Store Sydney ad:

A Sea Hornet speargun ad:

Cover of a Sea Hornet product list:

I've noticed the resemblance between the Australian diving equipment brand names Sea Bee and Sea Hornet. Are they somehow related?

DRW

[nikeajax]

Excellent thanks guys: it's so refreshing to see something different! It looks like they were riffin' off of the ScubaPro 109, but this one goes to 11...



Do you have any of their older gear?

JB

[Fibonacci]

The Command Air is most definitely better designed than a Scubabpro 109... it breathes better and has an o-ring sealed adjust shaft to prevent ingress of salt water and corrosion of the threads! 
Something Scubapro only got around to fixing decades later on the G260... just sayin' 

Sea Hornet MK 1-2 by Graeme Cameron, on Flickr

Sea Hornet MK 6-S by Graeme Cameron, on Flickr

Sea Hornet Mk 6_6S by Graeme Cameron, on Flickr

Performance figures with various first stages:
MK 1 piston first stage could deliver 1800 L/min from one port

MK 6S diaphragm first stage could deliver 1850 L/min from one port

Command Air second stage could deliver 1000 L/min with a sensitivity of 0.5 to 2.0 inches of water via the adjust knob at 10 BAR (145psi) Intermediate Pressure

Commander second stage could deliver 1400 L/min with equal sensitivity... teamed with a MK 6S this was marketed as THE deep water reg, and was used by the Royal Australian Navy (RAN) clearance divers and other specialists.


Command Air diaphragm LHS G250 RHS


Command Air vs G250 diaphragms_small by Graeme Cameron, on Flickr


Command Air Ad 2 1990 by Graeme Cameron, on Flickr

A batch of B-Commanders being prepared for the Royal Australian Navy (RAN)
B-Commander RAN 2000 assembly by Graeme Cameron, on Flickr

The B-Commander was the pinnacle of the Command Air design, only 1500 were produced for the RAN and are extremely rare these days. Note the change to a lightweight gas-flowed plastic poppet and revised Turbo boost collar.

Sea Hornet B-Commander parts by Graeme Cameron, on Flickr

[scubasteve]

Fibonacci, so you know which first stage was used by the RAN in conjunction with the B Commanders?

[tomcatpc]

And yet another company I have never heard of until today! I echo Jay's comment about the similarity to the Scubapro 109. That just looks way complicated to me!!! Then again the 109 I rebuilt was a bit of a handful for me.  
Mark