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ROB DAVIE · 17th March 2005, 20:37

Dave C,

You originally asked about a computer to use for the style of diving that we, as re-breather creatures, will do. There are only two. One is the VR-3, and the other is the Hydro-Space Explorer. They are both excellent computers.

The reason that there are only two is that we have to have (if we care about redundancy) a computer that will act as a back-up to our main PPO2 control system, whatever that may be, in terms of a real-time, independent PPO2 read-out. Both of these computers offer the sensor link to a stand-alone O2 sensor which also allows real-time deco computation based on the changing fraction of inert gas. (Assuming, of course, that the user is diving a fully-closed CCR.)

Further, both of these computers offer multiple gas choices, and multiple adjustments to both gradient factors and “conservatism” factors.

From this point, there is some divergence. The H-S Explorer is slightly larger than the VR-3, and has a large, easily readable display. Its visual display is very intuitive, and easily understood. The operating buttons have been criticized by some, but one must understand that they were designed to be used by a diver wearing gloves.

It uses either the Wienke RGBM, or the Buhlmann model, and the user may switch between the two. This is, as far as I know, the only one with this capability. The bubble model, of course, is a more modern algorithm and is better suited to dealing with our friend, Helium. It is made in the USA, which is good for our European friends, but not so good for our Canadian friends.

The VR-3 is a solid technical diving computer, built in England, and has a good track record in the community. Its algorithm, at the moment, is Buhlmann-based, with “tweaks” installed by Kevin Gurr, the creator of the VR-3, to make it do what we want it to do. There is report of an up-coming release of VPM-B for it, but “no firm release date has been announced” as they say.

It does have a color screen-upgrade, and a tweak that provides larger numbers to make it easier to read. Both of these are available at a reasonable cost.

Either of these units would be a good choice for re-breather diving, especially using helium, and going deep. They are both quality pieces of equipment. Both companies are committed to customer support. You should endeavour to get hands-on with each, and see which one you favour.

(Note: In the interests of full-disclosure, I know the makers of both of these computers personally, and have nothing but the highest respect for them.)

Rob Davie

17th March 2005, 20:37	#10 (permalink)
ROB DAVIE Administrator Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Feb 2005 Location: HOUSTON, REPUBLIC OF TEJAS Posts: 1,120	Which computer? Dave C, You originally asked about a computer to use for the style of diving that we, as re-breather creatures, will do. There are only two. One is the VR-3, and the other is the Hydro-Space Explorer. They are both excellent computers. The reason that there are only two is that we have to have (if we care about redundancy) a computer that will act as a back-up to our main PPO2 control system, whatever that may be, in terms of a real-time, independent PPO2 read-out. Both of these computers offer the sensor link to a stand-alone O2 sensor which also allows real-time deco computation based on the changing fraction of inert gas. (Assuming, of course, that the user is diving a fully-closed CCR.) Further, both of these computers offer multiple gas choices, and multiple adjustments to both gradient factors and “conservatism” factors. From this point, there is some divergence. The H-S Explorer is slightly larger than the VR-3, and has a large, easily readable display. Its visual display is very intuitive, and easily understood. The operating buttons have been criticized by some, but one must understand that they were designed to be used by a diver wearing gloves. It uses either the Wienke RGBM, or the Buhlmann model, and the user may switch between the two. This is, as far as I know, the only one with this capability. The bubble model, of course, is a more modern algorithm and is better suited to dealing with our friend, Helium. It is made in the USA, which is good for our European friends, but not so good for our Canadian friends. The VR-3 is a solid technical diving computer, built in England, and has a good track record in the community. Its algorithm, at the moment, is Buhlmann-based, with “tweaks” installed by Kevin Gurr, the creator of the VR-3, to make it do what we want it to do. There is report of an up-coming release of VPM-B for it, but “no firm release date has been announced” as they say. It does have a color screen-upgrade, and a tweak that provides larger numbers to make it easier to read. Both of these are available at a reasonable cost. Either of these units would be a good choice for re-breather diving, especially using helium, and going deep. They are both quality pieces of equipment. Both companies are committed to customer support. You should endeavour to get hands-on with each, and see which one you favour. (Note: In the interests of full-disclosure, I know the makers of both of these computers personally, and have nothing but the highest respect for them.) Rob Davie __________________ [SIZE=2]"CC Rebreathers will become a viable part of tech diving [U]WHEN PIGS FLY[/U]!!"--GI3[/SIZE]
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