Hollis Prism 2 CCR

[FloridaScubaDepot]

Hey Caveseeker7,

I was at the training Nick spoke about. It was a Blast! We had Peter Ready (Original Prism engineer extrordinare(?) ), as well as Matt Addison & several other prism rebreather instructors, too. As well as the VP of Sales/Marketing for Hollis, several Hollis reps from around the country, and one of their engineers, too. All together about 14 people.

It was really interesting to be with this crowd. Not only did we learn the Prism/Prism 2 inside & out, & dive it a bunch, but the Hollis crowd was intent in getting feedback from us. Some attendees were completely new to rebreathers, others were instructor trainers on other CCR units, etc. Some had SCR experience and so on.

I suspect some of the input provided will be able to enhance the production units in the future... there were a lot of ideas shared & discussed between the entire crowd (& some discussed in private between the Hollis guys!)

The cool thing is that Peter himself thinks the Prism 2 will be a fantastic by Hollis, and has a lot of faith in its future development.

That's it for now...

PS... looks like one of your pics is with Peter, am I correct?

 

[caveseeker7]

Yes, I took it in Catalina when Fabian Cousteau did his open water dives with Pete.
The Hermosa Beach shop was about half way between my place and the areas where
many of clients were. As L.A. traffic goes, I stopped by rather frequently "sitting out"
a rush hour or three.

Matt Addison is a really nice guy. Some nice mods to his PRISM I think, well executed.
Would have loved to be around for training/feedback/brainstorming session. A lot about the PRISM is very well thought out, and most of it implemented likewise. Some areas could do with improvements. Am looking forward where Hollis will take the unit.

 

[caveseeker7]

After reading your L.A. traffic assessment I realize you taking an optimistic view,
but I thought I asked anyway ...

We plan to start shipment in April 2008

Any news on the PRISM front?
Evaluations done, changes decided upon?
You still planning on shipping next month?

 

[Hollis Gear Nick]

After reading your L.A. traffic assessment I realize you taking an optimistic view,
but I thought I asked anyway ...

Any news on the PRISM front?
Evaluations done, changes decided upon?
You still planning on shipping next month?

Hey Stephan,

We have recently had several meetings regarding introducing the Prism2. One topic required working units in June for instructor training and for instructor candidates to gain hours of use with. But to make a long story short, production starts July 1st; ramping up volume through the end of the year.

As we get closer to the release date several websites/dealers have asked us to create a blog. This will be available to help everyone track to progress of our Prism2.

Thanks,

 

[caveseeker7]

Thanks for the update.

 

[caveseeker7]

Hi Nick,

another two have gone by, so I thought I give it another try for updates on the PRISM 2. Surely there must have been some developments since your initial reply, and since getting trained on the Topaz. And with instructor training to commence next month I assume changes to the Topaz have been decided on and are being implemented on those training units.

So what are they?

Changes to the material?

Changes to the electronics (hard- and software)?

Changes to your schedule?

 

[Hollis]

Stefan, thanks for the ping regarding our progress.

In a nutshell it is going very well, though a little slower than we would like.

We have implemented most of the items we discussed in our last post.

The re-design work is 95% done. Peter is very active in this effort; he and the project engineer meet every few days to review progress and direction.

You asked about material changes. Yes, we are will be using high strength ABS for the Prism2. We are also changing the manufacturing process for these components; we are building injection tools, molds if you will. The ABS is injected under high pressure and at a high temperature into the mold, the mold is chilled and the part is removed for post mold finishing operations. It can take several months to build and tune the molds. This is an iterative process where we receive the parts from our vendor, inspect the parts for conformance to the original engineering specification, we note any discrepancies, advise the vendor of changes required, they then modify the tooling and send revised parts for our inspection. Just a quick FYI, these tools are made from a special grade of steel, the tool to make a small plastic part is about the size of a small microwave oven, and they just get bigger and heavier from there.

We will start receiving parts from the new injection tools next week. We hope to have corrected parts for the breathing loop in late May or early June.

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 eliminates the LP Swivels that the Prism uses. All of this is in construction and should be ready in a few weeks.

You asked about changes to the electronics? 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.

We are now planning on being able to assemble the first Prism2 in late June. This will begin a process of developing manufacturing procedures, in process inspection criteria, life cycle testing of assemblies and subassemblies, and final inspection criteria. We will also be doing conformational testing on the Prism2 to assure that the oxygen setpoint controller and scrubber work as well as the Prism’s.

Once we are satisfied that the rig will not dissolve in the sea, we can do some diving with these beta rigs and plan additional production. Our current plan has a small lot of Prism2 rebreathers ready for instructor training in August. We will build additional rigs for our new instructors to get time on. We will have full production capacity in 2009.

We also need to develop user manuals, service manuals, training standards, and packaging. We will need to set up a supply chain able to deliver service parts, special tools, spares kits, and consumables such as absorbent, disinfectant, lubricant, etc.

I hope this answers your questions. We have a busy schedule for the next few months, but this is an exciting time too. We will start to see a new product come together.

Hollis.

 

[silent running]

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

 

[silent running]

Hello Hollis, I'm wondering why the scrubber duration on the Hollis website is listed as 245 minutes @ 1.3 lpm CO2 and not the 255 minutes @ 1.35 CO2 which was listed in the NEDU tests posted on the Steam Machines website. Was there another test done, or is this just a mistake made when quoting the NEDU data?

 

[Hollis]

Silent Running, Andy

Thank you for the post, questions, and testimonial!

In working on the re-engineering of the Prism, our first objective is to bring all the wonderful aspects of Peter’s Prism forward, with slight changes, to allow us to manufacturer the Prism more efficiently.

Our determination to do this with Peter’s Prism is in a large part based on input from divers like you who have a depth of experience in open circuit systems. Time and again we have been told of the durability of the Prism, and its ability to be field serviced so no dives are missed. Peter makes the excellent point about the oxygen sensor driven analog Secondary Display, that in the event of a loss of the system electronic oxygen set point control, the dive can continue as planned, just using manual control.

The Prism2 counterlungs will be attached just like the Prism counterlungs. There will be a Velcro gator and side release buckle at the top and the lower attachment will be another side release buckle that will attach to the harness waist strap, and the counterlungs will act as the shoulder strap. We will add a 2 inch D-ring on the outboard side of each counterlung at the middle of the length of the counterlung. We will retain the integral weight pocket.

Regarding bail out cylinder mounting; the envisioned configuration is to clip the valve to the D-ring on the outboard side of the counterlung and the lower attachment point is a D-ring mounted where the waist strap meets the backplate. From looking at Jill Heinerth’s video about side mounting on a rebreather, the Prism2 would be adaptable to that system too. We agree with you regarding drag, streamlining, and ease of use. Also comfortable, efficient, and enjoyable are all good words to use in safe dive equipment design.

We are going to change the waist strap to 2 inch webbing, with an optional cummerbund, and some pocket options including ditchable weight pockets, similar to the waist harness on the Hollis HTS. Based on input from Tech divers we will be using a crotch strap, rather than the thigh straps the original Prism uses, but the system will adapt to thigh straps. We are working on a design that will allow lots of customization. We should have this done in 6 weeks or so. We are also investigating an adapter to allow the use of tech metal backplates; we will have to revisit the counterlungs so they can be attached to the backplate’s shoulder straps.

We are working on tweaking the BC. Our concerns echo yours; we want great balance for horizontal trim, and a BC that is not going to get pinched when the Prism2 is placed on a bench in a vertical orientation for donning.

We like the analog Secondary Display too. We have a design effort underway to develop a battery powered digital Secondary Display, and we will continue to make the oxygen sensor powered analog Secondary Display that you like. It is indeed impressive to hear divers discuss an electronic mixed gas rebreather where a failure in the electronics is no big deal.

We are keeping an eye on servicing the Prism2 during our redesign efforts. We expect to deliver the Prism2 with most items user serviceable, and some items would require returning to a competent service facility, and some items would require returning to the factory. Most items can be swapped out; we will have spares readily available. Replacing some items, like the solenoid, would require access to the electronics housing, not something done casually. Calibration of the depth transducer would require specialized equipment, and would probably require returning the Prism2 scrubber head/electronics housing to the factory or specially set up service center.

We are planning on an optical data out port to transmit real time PPO2 to a dive computer. We are also planning for onboard logging of time, depth, and PPO2. We will have download of this data by USB, just like a dive computer with a PC application to save and display the data graphically and in analog mode. We do not want to disclose the algorithms we are considering at this time, one is new and revolutionary, one is established and well tested. It would not be too hard to make a black box that would convert the optical output PPO2 to a voltage value that would mimic an oxygen sensor.

We plan to have comfortable carrying handles on the top and bottom of the Prism2. One change from the Prism is where the cables plug in. We will use 90° fittings on the cables to attach to receptacles on the bottom of the electronics housing. This will let us rout the cables away from the carrying handle. With the exception of the cable to the Secondary Display the other cables will be well protected.

In regards to scrubber duration, the 255 minutes (4 hours, 15 minutes) was the average of several runs done by the NEDU in Panama City. The dives we done with an injection rate of 1.35 SLPM of CO2, a RMV of 40, water temperature of 40 F, at 60 FSW. The time given is the time it took to reach 0.50% CO2 SEV. Scrubber duration is very dependant on depth, water temperature, work load, and varies lot to lot of scrubber material. Shallow warm water where the diver is just observing marine life will yield the longest time, and deep cold dives swimming into a strong current will yield the shortest duration. The 245 minutes looks like a typo, thanks for pointing it out.

We have all of the injection molded components for the breathing loop in hand and are working with our suppliers to correct minor non-conformities in the components. The design package will be finished this week, which is delaying our schedule to build the first Prism2. With luck we will assemble a Prism2 in the later part of July or early August. Then the testing begins.

Hollis