First Rebreather - Used Prism 2 - Good Instructor - Is it OK ?

[Narcosis Mike]

Electronics are the 12-light / version 2 with Petrel. I took the plunge and went for it. MOD 1 Class starts Saturday and am looking forward to it. Now i just need to keep pestering a dealer who is selling me the 3L tanks and the other dealer shipping me the hollis valves to hurry up and send them... Seems to be a local shortage on 3L tanks.

Also - I went ahead and ordered the BOV for the unit. What's the best way to plumb it to DIL - should I go straight to offboard and maintain a backup second stage for redundancy? While i'm a long way off from taking the MOD 3 class, when that time comes do most get some sort of splitter or switch that lets you change the BOV feed from normoxic to hypoxic bailout?

Lastly, I found an experienced instructor who will teach the TDI Advanced Wreck (penetration class) with the P2, which is my ultimate goal for the CCR, but living about 4 hours from the best caves in the world I can't help but think it's going to be in my future. Who are some go-to Prism guys for cave training? I am currently only cavern certified so would be almost starting from the ground floor in that realm.

I appreciate the knowledge and expertise from all of you guys.

 

[grantctobin]

Electronics are the 12-light / version 2 with Petrel. I took the plunge and went for it. MOD 1 Class starts Saturday and am looking forward to it. Now i just need to keep pestering a dealer who is selling me the 3L tanks and the other dealer shipping me the hollis valves to hurry up and send them... Seems to be a local shortage on 3L tanks.

Also - I went ahead and ordered the BOV for the unit. What's the best way to plumb it to DIL - should I go straight to offboard and maintain a backup second stage for redundancy? While i'm a long way off from taking the MOD 3 class, when that time comes do most get some sort of splitter or switch that lets you change the BOV feed from normoxic to hypoxic bailout?

Lastly, I found an experienced instructor who will teach the TDI Advanced Wreck (penetration class) with the P2, which is my ultimate goal for the CCR, but living about 4 hours from the best caves in the world I can't help but think it's going to be in my future. Who are some go-to Prism guys for cave training? I am currently only cavern certified so would be almost starting from the ground floor in that realm.

I appreciate the knowledge and expertise from all of you guys.

Why not go learn cave on OC and then do the crossover? It tends to lead to a better understanding of self mortality. I’d argue straight to CCR Cave is a poor choice for the overwhelming majority of divers. If you’re hellbent, please don’t try it for at least a couple hundred hours.

 

[vitaly]

Check diverightinscuba for 3l tanks and hollis valves. I just ordered one more tank (4th in my collection ) last week. BTW Hollis valves look cool but regular inline valves work fine too. I prefer Hollis but all my buddies use regular inline valves.
There are different views on using BOV on hypoxic dives. Some instructors might even reject to teach you if you have BOV connected to onboard hypoxic dil. I wouldn't worry about it till you are ready for MOD3 then ask your instructor.
Regarding P2 cave training I would highly recommend Lawrence Babcock. But don't rush. Although I don't agree with @grantctobin that you have to learn cave on OC first I totally agree that you need to get 100-200 hours on you unit before starting the cave training. I personally took my intro to cave with ~120 hours and hypoxic certification under my belt.

 

[rjack321]

Splitter valves are how you die. No splitter/switches ever.


Manifolds and Switch Blocks
Every time we sell a manifold or switch block, we shudder a little bit. The gas switch block is used in primarily by surface supply divers to switch from surface supply to emergency bailout gas. Manfolds are primarily used in gas distribution systems. But the key here is that there are not different gas mixtures involved. Unfortunately divers sometimes get the idea to match these products up with multiple cylinders and/or or quick disconnects to create some type of elaborate system for rapid switching between different gas mixtures and/or cylinders. Gas switching errors are very often involved in technical diving accidents. Over the years we've learned about several near misses and fatalities that were directly attributable to mistakes with switch blocks that were connected to different gas mixtures. No matter how careful the diver, or how many safeguards, we think using switch blocks with different mixtures is a very bad idea.

 

[ChuckP]

Splitter valves are how you die. No splitter/switches ever.


Manifolds and Switch Blocks
Every time we sell a manifold or switch block, we shudder a little bit. The gas switch block is used in primarily by surface supply divers to switch from surface supply to emergency bailout gas. Manfolds are primarily used in gas distribution systems. But the key here is that there are not different gas mixtures involved. Unfortunately divers sometimes get the idea to match these products up with multiple cylinders and/or or quick disconnects to create some type of elaborate system for rapid switching between different gas mixtures and/or cylinders. Gas switching errors are very often involved in technical diving accidents. Over the years we've learned about several near misses and fatalities that were directly attributable to mistakes with switch blocks that were connected to different gas mixtures. No matter how careful the diver, or how many safeguards, we think using switch blocks with different mixtures is a very bad idea.

Forgive the stupid question - In an open water dive to 100m, hypoxic, you really only need one gas plugged into your BOV correct? I mean you could breathe 10/xx all the way to 20' really other than the deco stops?

Plugging into the BOV - you bail at 100m, you obviously are carrying I'd guess two deco mixes plus your bail out gas - when you switch to your first deco gas, it's not an unplug and plug the new gas in is it? It's a switch from your BOV to an open circuit reg correct?

 

[vitaly]

It's a switch from your BOV to an open circuit reg correct?

Regardless of depth and mix plugged to your BOV if you have to bailout just switch to OC reg.

 

[grantctobin]

Regardless of depth and mix plugged to your BOV if you have to bailout just switch to OC reg.

Meh. Anyone running a BOV should have it plumber into an adequately sized BO bottle (AL80 or bigger, maybe AL40 for sub 30m dives). Exception being for caustic loop.

 

[rddvet]

Regardless of depth and mix plugged to your BOV if you have to bailout just switch to OC reg.

This makes zero sense to me unless your BOV is plumbed to a tiny onboard cylinder which is deadly stupid. Why have a bov if you're bailing to oc.

Meh. Anyone running a BOV should have it plumber into an adequately sized BO bottle (AL80 or bigger, maybe AL40 for sub 30m dives). Exception being for caustic loop.

Correct answer

 

[rjack321]

Forgive the stupid question - In an open water dive to 100m, hypoxic, you really only need one gas plugged into your BOV correct? I mean you could breathe 10/xx all the way to 20' really other than the deco stops?

Plugging into the BOV - you bail at 100m, you obviously are carrying I'd guess two deco mixes plus your bail out gas - when you switch to your first deco gas, it's not an unplug and plug the new gas in is it? It's a switch from your BOV to an open circuit reg correct?

There's much internet handwringing over jumping in with a BOV plugged into something which isnt breathable at the surface. So people create convoluted mechanisms with switchblocks or plug and unplug travel gases during the descent, or all sorts of nonsense. The simplest solution is right there (if you are forced to bail on the surface). Close the DSV, switch to any deco gas. Keeping a deco reg in ready to deploy state is dirt simple and if you want the deco gas later it needs to be accessible anyway.

 

[vitaly]

This makes zero sense to me unless your BOV is plumbed to a tiny onboard cylinder which is deadly stupid. Why have a bov if you're bailing to oc.

Switch to OC mode is easier and faster with BOV. It also helps if you need to take a few sanity breaths in case of CO2 hit. Other than that using OC reg is more convenient way to bailout especially in case of switching gases for deco. Also all my BO regs are more comfortable to breath than my Hollis BOV but you milage may very