Hello Hollis, thanks for keeping us up to date on the progress of the Prism 2.
We are also working on the Buoyancy Compensator, Counterlungs, Backplate, and Harness, we had these at DEMA and did some diving with the Prism2 BC and harness in Florida in January. We have a new concept regulator for the Prism2 that eliminatesthe LP Swivels that the Prism uses. All of this is in construction and should be ready in a few weeks.
I've had a Prism for over 6 years now and would like to give you some input regarding the back plate/harness/BC combination. The stock setup is very comfortable and is easy to slip in and out of thanks to the fastex clips that hold the counterlungs to the waist and their functioning as the shoulder strap/weight baring part of the harness. This is a much easier, faster system than any of the other CCR makers currently use. However, the downside is that carrying open circuit bail out with the stock arrangement is not very comfortable and puts the BO cylinder too low, where it interferes with the legs. Also, in my opinion, standard sling tank mounting increases a diver's hydro drag too much. After experimenting with different arrangements, I have settled on side mounting my BO tank, which keeps it low, under the arm and along the same line as the diver's spine. I barely notice the tank is there and since I switched to this system, I have been much more comfortable diving in strong currents, which I and many other recreational divers regularly encounter in places like Asia. I believe streamlining is not just about comfort, it's also a safety issue as high drag creates more workload and makes managing strong currents more difficult. I hope you will consider a side mount option for carrying open circuit BO tanks, as I believe they are easier to use and easier means divers will carry BO more often, which can only increase safety.
Also, although the stock BC provides excellent trim, it is donut shaped and hangs down below the tanks, which allows the potential for it to be chafed and punctured. I hope you will switch to a u shaped bladder to keep it from being stuck under the unit when it is sitting upright. I know that it might mean slightly less good trim in the water, but this can easily be offset by proper weight trim.
Speaking of trim, being a warm water diver, I don't need too much weight on the Prism, so placement of those few pounds is crucial to keeping good horizontal trim. I have mounted 2 small nylon weight pouches on either side of the top of the cowling, directly above each cylinder. This puts lead at the highest point on the unit, which makes staying horizontal effortless. It also makes adding or getting rid of weights very easy, say if the next dive site requires a thicker wet suit, as happened a few times diving in Indonesia. I no longer use the weight pouches in the counterlungs as I found them to be uncomfortable when using anything but shot pouches, which are not commonly found in most dive operations.
Lastly on the subject of the harness, it would be great to have a rubber covered cloth handle mounted above and behind where the display and on/off cable ports are. The current handle area is too close to the cable ports and has the potential for someone to grab and pinch the cables when picking it up there. For this reason, I try to avoid having any dive staff pick up the unit without me, meaning that I always have to get out of the water with the unit on, which can be be very difficult when trying to climb into a small boat with no ladder, like a RIB.
We are working with the original programmer, and the board house, that made the Prism electronics; we want to retain the excellent features of the Prism with 2 small additions. We are planning on adding some memory for data logging with a 3 pin USB download of dive data. We will also have a data out port to interface with a dive computer we are working on. These changes will be completed, tested and installed in the Prism2 in time for the first production run.
Hollis.
The additions to the electronics sound very nice. Can you tell us which decompression model the dive computer will use? And will it be connected by an optical cable to the head and include real time O2 cell/PO2 input?
I have over 500 hrs on the Prism and have had no missed dives, which I believe is mostly due to it's simplicity and ease of use. I hope you will keep the passive needle gage 2ndry as not only is it a major safety benefit, but it allowed me to continue an expensive Komodo trip, diving the unit as a manual O2 addition CCR without electronics, after the solenoid blocked up with corrosion. Which brings me to another suggestion, it would be best if the solenoid could be quickly changed out by the user in the field with no special tools. I don't think this is possible on the current Prism, but really just amounted to an inconvenience in the above situation. By contrast, I have a buddy who sold his Evolution after the solenoid failed and the unit locked him out from diving for the remaining 7 days of a very expensive trip. Keeping an electronic CCR simple, with all crucial parts being user replaceable, increases reliability and safety, which of course also keeps users happy and loyal.
Thanks again for keeping us informed about the Prism 2. I'm very interested in it's development as my open circuit diving girlfriend is tired of hearing about all my great wildlife encounters and wants to move over to CCR... -Andy