Mark Chase

In response to this question:

AM,

You and Alex swayed me. I'd like to see the list. This isn't about all RBs being unsafe in certain people's hands. It is about a few RBs being unsafe in trained hands.

So, once again:

Alex, what is your list of poorly engineered RBs that will produce widows and orphans so we can be informed.



Id like to start off offering the following on the units i have intimate experience with:

NOTE: since this thread has started other divers have kindly contributed their thoughts. As a result the following list is now open to all and not just my ideas.


KISS

• Routing of the hoses inside the counter lung case can restrict / significantly increase the WOB
• Flood tolerance is very very limited.
• Flood recovery is virtually zero
• Diluent flush difficult to not possible without breathing the gas.
• No opportunity for off board gas addition
• The Paragon BOV is a lousy unit to bailout on to
• The ADV design doesn't allow decent negative tests and is prone to failure
• The OPV doesn't allow for a decent positive test without modification.
• No HUD on standard unit
• Cell changing, calibration, battery changing and scrubber removal is tool intensive
• Poor history of flooding to PP02 displays

Sport KISS

• Correct installation and checking of Counterlungs difficult/may be ignored due to complacency
  
• Scrubber connections to pods and CL's prone to leakage
  
• Absolutely not a single hope in hell of doing anything about a flood coming from the hoses/BOV, water straight into the scrubber.
  
• Scrubber could come loose and float free causing huge WOB issues/floods on early models (new models upgraded to fix this)
  
• Poor life from oxygen sensors (compared to majority of Rebreather's getting 12months, SK gets 6 if you are lucky, IME)

Classic Inspo

• Free O ring on scrubber easy to forget
• Hand set magnets rust and fail
• Micro switches prone to failure
• Battery's allowed to off gas in to loop
• Battery box has single point failure on lid
• Battery box prone to corrosion
• Loom prone to corrosion
• Wire in loom prone to breakage
• Handset cases prone to cracking at gland
• Cell 2 gets condensation dripping on it from adjacent screw.
• Clutter in head makes wire damage and stress on molex connections likely
• Known software faults in hand sets.
• No HUD
• No BOV
• Manufacturing tolerances in scrubber and mouthpiece poor to the point where jamming in use is a regular occurrence.
• Isolation of 02 feed to solenoid not possible
• Backlighting inevitably fails eventually without any means of repair other than a new controller module.
• Two handed oporation to close mouthpiece
• Older units suffered battery bounce on badly designed battery box. Upgrade available
• Older units had no back light to hand sets. Upgrade available
• Special tools required for hose conections and cell changing

Hammerhead CCR Head for Classic Inspo and other units

• All units very sensitive to battery issues. Bateries must be checked under load prior to use to avoid potential failure
  
• Nickle hand sets prone to electrolytic effect on surface where nickle is chipped.
  
  Anodized Aluminum Handsets:
• Contact issues due to oxidation on the threads of the battery compartment.
• Week depth sensors
• Rebooting program issues that result in spiking of O2 at depth (free upgrade available to prevent this)
• Loss of all deco info on reboot
• Inability to isolate faulty primary controller if it fails and locks into the reboot cycle.
• Displays can be hard to read in certain situations.
• Time to surface times are not acurate.
• Battery life is limited to a recomended swap with every scrubber fill.
• Last stop depth is fixed at 10' / 6m.
• Not possable to isolate 02 feed to solinoid
• HUD dificult to see in shalow clear water and good light
• Older wet switches turn on too easily and flaten the battery on the boat journy out. Dificult to turn off in rain or heavy seas. Plastic bags needed to keep hand sets dry.
• Could only be calibrated in 100%02

Standard rEvo MCCR

• 02 injection can not be operated with either hand
• Hud showing forth cell flashes red when forth cell not present getting the diver used to seeing red flashes
• Very limited / No flood recovery
• Limited flood tolerance
• No BOV
• Hand set displays only display two cells per hand set limiting comparison of cell performance
• HUD design makes right hand display dificult to see on the edge of peripheral vision
• Can only be calibrated in 100% 02
• Milivolt display only available on calibration cycle

Meg Apex 2

• Solenoid pipe gets lose and leaks. Easy to tighten, probably caused by using it as a partial handle when removing lid
• Handsets can dim when hot (30deg C)
• Potential bypass through cells - I have not seen this but do check them each time.
• Buckles on bottom of lungs can come undone. fix by replacing with p-clips.
• Angle of o2 hose to solenoid causes strain on quick disconnect.
• Above average incidence of 02 solinoids jaming on
• Material between screwthreads on handsets too small can crack - causing leaks that kill handsets
• Apeks 2.01j version had a default solenoid injection time that was inadequate to sustain any kind of PO2. One must remember to set the oxy-inject time to a safe value after every turn-on and before any dive. (this is a dis-continued version)
• The 2-point cell-calibration system is prone to errors by users, and can hide cell issues. An improvement would be a single point (@ PO2 = 1.0 or so) cal system, and to then just check that the cell falls back to .21 in air.
  

Vision:

• temp stick cable can get squeezed between the spacer ring and the o-ring what could lead to gas bypassing the scrubber (hypercapnia)
• solenoid cannot be isolated in when stuck open
• Single display for both onboard computers with proven duel failure potential
• No BOV
• Still has seporate 0 ring to seal scrubber inside canister
• Special tools required for hose conections
• Two handed oporation to open close mouthpiece
• Various internal clock and software bugs in early models. Generally repaired with free down-loadable upgrades.
• Bloom or dark spot on display caused by faulty batch of heat sink's. Repaired on service.
• Head of unit can be very difficult to separate from scrubber.
• Captive studs in scrubber head locking system easily damaged if scrubber canister is dropped.

O2ptima:

• Uses Hammer Head controler so shares comon faults with HH list above
• Frame, foot & backplate week. It shouldn't be necessary to have to strengthen the original
• No BOV's
• Loop Hose lengths cause issues with some divers

Boris:

• Early OPV leakage issue -fixed (all users sent free replacement)
• Some domes destorted causing leak -fixed (upgrade provided and dome redesign)
• Early design Hud flooding through broken faceplate -fixed (hud redesign)
• Some scrubber compression plate distortion (replacement, redesign, storing without o-ring)
• Counterlung leakage (supplier, material change)

Mk15.5

• Salt water ingress into secondary cable can screw up displayed ppo2
• old analog gauges fail easily (especially when knocked)
• Horeshoe board wiring easily corroded
• poor flood tolerance/recovery

So whats up with your unit?

__________________
Is it supposed to make that noise ?

I took my unit to the dive shop and demanded they bolt on every thing that would fit.

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"Doing It Chasey"Hammerhead Eccr Advanced Diving System