I sold my shearwater petrel so I could get Ratio ix3m. The ratio costs a bit more, but I thought it was worthwhile.
not a shearwater fan ?
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broncobowsher
Contributor
I wanted more transmitters. Two tanks plus deco, and as a bonus I can keep it paired to my wife's transmitter. There's a few other things it does that petrel does not, but that was the driver for me. Also, I prefer the physical push-buttons over the tap buttons on the petrel by a wide margin.
The non-replaceable but rechargable battery in ix3m kind of stinks when you're used to shearwater's superior solution. I thought the benefits outweighed the drawbacks.
It is of course a personal choice and a personal preference. However to give you some reassurance, my Eon Battery is 4 years old, and made over 700 dives, with lots of charging (I prefer to keep it topped off) Touch wood. So far (according to the computer) I know get 29 hrs off a full charge, rather than the 33 I used to get when new
But I do get the Pro's and cons with both
Apart from that do you like the Ratio? I'd love to find out more
Yeah, it's great. There are a number of things it does that I just don't use, such as VPM. There are other nice to have features that weren't mandatory like GPS. The screen is at least as good as shearwater's.. perhaps better. As I said, the physical buttons were a nice change. I didn't buy the model with a Fischer port for RB's as I don't see myself going RB anytime soon. I like the colored transmitters for OW diving. not so much in a dark environment in a cave, but they do have neoprene covers to solve that problem.
According to specs Ratios have a full IMU inside. If they'd logged its readings it could be fun trying to reconstruct dive trajectory afterwards and fit it to GPS start and end points. The manual reads like they only have an app to look at "pitch and roll" though, I saw nothing about logging.
Hatul
Contributor
Lots of people like Shearwater so I'm sure it's a fine computer, but I went with Scubapro G2. One thing I value from air integration is the Air Time Remaining and this is where Shearwater is deficient. If you happen to go into deco the Perdix stops displaying its Air Time (correct me if I'm wrong) whereas the G2 and other computers, such as Oceanics and I believe the new Suuntos, continue to include the deco stops and display the correct Air Time.
Other features I like about my G2 is the profile dependent deep stops which tell me when I'm starting to offgass the leading compartment and the heart rate monitor. The dependable rechargeable battery is icing on the cake as I don't have to worry about opening the battery compartment and the O ring issue.
Adam
Other features I like about my G2 is the profile dependent deep stops which tell me when I'm starting to offgass the leading compartment and the heart rate monitor. The dependable rechargeable battery is icing on the cake as I don't have to worry about opening the battery compartment and the O ring issue.
Adam
Kinda sorta but...
The Suuntos (at least) do do this. Your Gas time remaining (or Time to Die clock as I call it) does indeed take into account all your obligation when calculating your remaining gas time.
However it (Suunto) works this out using your "instantaneous" consumption rate from its last sample rather than the average consumption over the whole dive.
What this means in practice (as my wife found out when sending up an anchor on a lift bag) is that you can easily get a GR of zero while still havign sufficient gas in your tank. Sure if her consumption to the surface including her SS had been at the rate it was when filling a bag then that would be true, but of course it wasn't. In her case within maybe a minute after the next consumption samples had been made it was back to a positive GTR
Hence I teach people to be able to do the math in their head
Hatul
Contributor
That's a good point, and to use any number displayed by the computer you have to understand how it's derived. Of course filling an air bag is going to lead to a spuriously short air time, as the computer cannot distinguish between filling a lift bag or increased breathing. Nevertheless (assuming I'm not filling air bags or venting air) I find the air time number very useful, and if I see it getting close to zero I know it's time to ascend even though the tank pressure remaining may be considerable.
That of course is fair enough, that's what the function is for
I do it differently which might be of interest.
I know my SAC very precisely but I use a rounded up number that's easy to calculate - in my case 15l/min on a 15/tank equals 1 bar/min at the surface
But I might dive Al 80 (11.7l which I round down to 11)
Doing the maths and with a bit of rounding up - on a AL 80 amy rule of thumb to leave and depth, make a 5 min Safety my gas requirements work out at needing the same number of Bar as I am at metres depth.
So at 40 m I need 40 bar and 30 metres, 30bar etc
On a 15l cylinder it's half of that (40 metres = 20 bar and so on)
So a cursory look at my gas contents and my depth and I know at what pressure to start to ascend to honour my reserve on the surface.
I deliberately rounded up my calcs so they make nice round numbers which are easy to remember. They also have some "fat" in the numbers so I'm not required to make a 10m/min ascent.
Of course experience comes into it too so that I instinctively know anyway - but if I need a quick reference that's it
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