You need to think about worst case scenario and what simplicity offers over fancy gimmicks. I would hope that the oral inflation overrides the other parts. On a standard inflator it does. Of course all it has to override is a LP hose that is not deliviering air for some reason. I posted these guidelines in another thread that I use and that I teach my students to use. And in fact in training they are required to use them.
- Safe and Reliable
- Comfortable and Well Fitting
- Provide for adequate redundancy without being excessive.
- Configured for self sufficiency and self rescue
- Simple and Streamlined
- All accessories and valves easily reachable
- Allows for Buddy Assist and Rescue
- Has a Low Drag Profile- Streamlined
- Adaptable to the Divers Needs
- Adaptable to the Diver’s Objective
- All Equipment Identifiable by Touch and Location
- Standardized with Fellow Divers Yet Versatile to Meet the Needs of the User
- Equipment Placement is balanced and Instinctive
- Any Changes have been made Gradually and with Careful Thought
- Diver is open to Improvement to his/her Setup
- All Cylinders are Properly Labeled with the Gas Mixture, MOD, and the Diver’s Name
Pay attention to #'s 1,3,4,5,7,9,12, and 13.
#1. Safe and Reliable is pretty much any piece of new gear today. But those are relative terms. Safe is not just how rugged or well constructed the gear is. Safety encompasses much more. While it is true that your buddy should be aware of your gear and familiar with it's releases, valves, etc., you need to consider that your buddy may not be in position to help you for whatever reason. In that case will the person who does come to help you know what to do? What if they have never seen the type of BC you are using. They have to take precious seconds to try and figure out how to put air in your BC. Precious seconds where you could lose consciousness and slip out of their grip. And given that there are reports of the lever being hit and activated accidentally, damaged, or otherwise compromised is it worth the risk?
#3. Provide for adequate redundancy without being excessive. Ok you have an oral inflation tube in addition to the lever mechanism. Will a resuer know to look for? Is it enough redundancy? Is the system of levers, rods, and tubes good redundancy for the oral inflation in no one knows how to use it. Will you be calm enough to use the oral tube when your lever system fails and you also have to try to work it with gloves on.
#4. Do you plan on practicing with the system to the point where you will instinctively know how to respoind to an emergency? Can you unhook the LP hose without looking in bad vis when you are stressed and at the same time see what you are doing? And don't forget that you may need to make a repair on the system to keep diving. A std inflator can be taken apart and serviced in the field with just a couple simple tools and new orings.
#5 While it may be stream lined, so is a std inflator that is not overly long and properly secured. However it (the I3) is not by any means simple. If you cannot access every part of the mechanism it is too complicated with too many failure points for my tastes. Each rod, lever, tube, connection is a potential failure point and therefore not acceptable to me.
#7 This means your buddy and potential buddies has to be intimately familiar with the use of the mechanism and not get confused or flustered should they need to help you. If they have to ask themselves do I push down or pull up it is too much. Can you guarantee that you will fully educate every person you will dive with how this thing works. A std inflator is pretty much universal and what most people have been trained on.
#9 If you want to change your gear it should be easy and quick with no worries about how the other items will be affected. Replacing a std inflator hose with a longer or shorter one is easy. If you want to do deep dives at some point you should also be seriously thinking about how you will carry a redundant air supply. You sure can't use doubles with this and if you sling a stage as is often done you'll cover up the mechanism. And will you remember to use it or not use if you put a std inflator on?
#12 Are your dive buddies going to be using a similar set up so that they don't need to think about how to respond and will you find yourself looking for their lever in an emergency when they don't have one?
#13 Critical point, Balanced does not just mean weight wise. are the items you will need going to be able to be carried or stowed so that you are not over loading one side of the body task wise? And will you be able to instinctively reach and get an item or stow it?
Things to think about.