Inspiration Modifications

[Mark Y]

What modifications have to be made to the Inspiration to dive it beyond 330 ft?

I know the buzzer can implode (how to you remove it?)... but what else???

[ghosch]

I'm not an expert on the Meg, but I believe the most significant difference (as it relates to deep diving) is the breathing hose diameter, and how it impacts work of breathing at depth.

[rcojr]

The first problem you encounter with the Inspiration is the buzzer imploding. You can either replace the scrubber lid with a Hammerhead (big bucks)or some people have removed the buzzer.
I don't like the idea of just removing the buzzer and not having any warning system.
I am checking in to the possibility of replacing the buzzer with a red LED like the Megladon has in it's heads up display. That way you would have a red light blinking in your eye instead of a buzzer in your ear.
Beyond that people have been diving the Inspiration well past the factory rating of 100 meters(330 ft).

[john j]

Hi Mark;

The buzzer is factory tested (but not factory certified) to 528 feet.  Beyond that depth it doesn't actually implode.  Common misconception.  The buzzer is actually inside the plastic canister at the end of that hose.  Inside that hose and inside the buzzer canister, the pressure is the same as in the breathing loop, just about ambient pressure.  If taken too deep, the buzzer canister does not implode or crush in.  Only the buzzer element inside the canister crushes.  The buzzer then stops working.  So, when the buzzer "implodes" you don't get a loop flood, you just get a buzzer that doesn't work anymore.

From what I have heard, most divers going very very deep (and there aren't many going that deep) will just remove the buzzer.  They just just cut and seal the wires, remove the assembly and plug the hole.  I wouldn't recommend that, but that's what I have heard.  Hammerheads are less commonly used than you might be lead to believe.

[Bill M]

Here is a website with a description of what can happen to the Inspiration Buzzer at certain depths well beyond the unit's designed capabilities. [url][/url]http://www.deepcave.com/images/Komati_Dive_Trip_Oct_2003_deepcave_version.pdf

This guy did however die in the same cave that he is talking about.

[Mark Y]

Thanks John.  I wasn't worried about the loop, but the electronics and how they might be affected.  I don't intend to remove the buzzer, yet, as 500 ft. dives are for next year...    I've looked into the Hammerhead units but don't plan on getting one... the cost and the unit I have seems to work just fine!

Bill, I've checked out .  It is an interesting site... too bad it won't be expanded upon.

Are there any other equipment concerns when breaking the 300 ft. barrier?

[john j]

I use an off the shelf Inspiration for 300+ foot dives.  I'm not a big fan of all the little modifications and I'm not a gadget junky.  I think keeping things as simple as possible is usually best.  I'm not knocking the people that come up with the modifications, there are some really clever ideas out there.  I personally don't feel a need for them however.

I've had mine on something like 45 dives beyond 300 feet, with a maximum depth of 330 feet, always in cold water and it performed just fine. 

Scrubber life is going to limit you if you are contemplating 500 feet.  You may end up having to do some of your deco on OC unless you keep your total dive time under 3 hours, or just keep bottom time short.  In the past, I used to push the scrubber limits, but have recently been enlightened on the true danger of that, so I'm not doing it any more.  The scrubber lifetime and depth rules are real, based on real data.

If you upgrade to the Evolution electronics, you can sometimes extend the scrubber life becasue they have the scrubber monitor.  It is important to know that the scrubber monitor does not measure CO2.  It only measures scrubber temperature.  Temperature is realted to scrubber effectiveness, but is not a direct measurement of CO2 levels.

[rcojr]

When the Buzzer implodes a little more happens than just the buzzer doesn't work anymore. This is from the Inspiration User Group Archives. Martin Parker is the owner of AP valves, the company that produces the Inspiration. A little more than I want happening on a deep dive.




Excerpt from a recent email sent to the list by Martin Parker

"The last depth record dive to 224m by three Germans sounds very glamorous to some but it was not without problems. On every unit the buzzers imploded after about 180m causing a critical short and dragging the power below the "brown out" threshold. The unit resets, tries to power the buzzer as it does when you switch on, the power shorts, the voltage drops below the brown out value the unit resets and so on and so on. So the screen shows the first display, goes blank, shows the first display, goes blank."

[Mark Y]

I haven't modified my Inspiration at all (except a few added 'D' rings).  John, I subscribe to your 'modification' philosophy.  Also, I'm a very, very long way off from a 500 ft. dive... I was joking.  I'm still working my way down to 300 ft., let alone anything deeper than that!  I have never pushed my scrubber duration either.  I don't like to gamble.

Bob, how did the three Germans deal with the 'brown out'? Sounds scary!

[rcojr]

Mark
My guess is that they would have gone into semi closed circuit mode and headed for the surface.
What about the 4th?
Bob