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In Pursuit of Perfection July 11, 2009

Posted by Chris Sullivan in Equipment.
Tags: , , , , , , ,

As mentioned a couple of days ago, upgraded software has come out for the Shearwater Pursuit, and I’ve just gone through the upgrade process.

Once the free upgrade has been downloaded and unpacked from the Shearwater web site, the next step is to make sure you have an Infrared port on your computer. My Dell Latitude D620 has a darkened window on the left hand side that looks suspiciously like an infrared port, but I can’t find any mention of it in the Windows-XP configuration.

Shearwater thoughtfully provided a infrared USB dongle for just this circumstance, along with a mini-CD with the driver and a short USB extension cable (in case you’re using a desktop system with the ports in the back or some other inconvenient arrangement.  The manual says that you can do a network installation of the infrared driver but this didn’t work for me so I used the mini-CD.

Then I ran the upgrade program which I’d unpacked from the download file, and it found the infrared port (it also sparked off a new installation procedure for a serial port over IR connection, which I thought about cancelling but instead opted to go ahead with a network installation while the upgrade was running – a risky procedure which worked fine).  I then put the Pursuit into upgrade mode and the software loaded in about 2 minutes.

Now finished with the  computer, the Pursuit started a lengthy decryption process. Both the download and the decrypt show a counter so you get the good feeling that something is happening. The counter runs very quickly during the download and much slower (about 5 seconds per count) in decrypt mode. The counter goes to about 312 in decrypt, which indeed takes most of the maximum half hour advertised by the documentation.

The Pursuit then asks to confirm the clearing of its internal decompression model (“Tissues Cleared”) and to confirm the upgrade reset, and then you’re done.

The first difference I notice while on the surface is the altitude readout. That’s pretty cool! It is reading 999 feet right now, compared to the elevation of my house at 952 feet that Google Maps advertises. As the barometric pressure right now is slightly above normal at 102.13kPa, it looks like it’s reading slightly high, but this is diving, not flying, and as I’m slightly elevated from the ground where I’m sitting it’s likely within the tolerances for altimeter setting, which is pretty good, I think. It’s certainly a big improvement over the 1 mountain, 2 mountain or 3 mountain display you get on the Apeks Quantum.

The new screen after the altitude display (which has been added to the current gradient factor on the 3rd screen) shows the “stored surface altitude in  millibars and ATA” at the time the computer was turned on. I was a little confused at first because this was showing 1013 after the upgrade, then 999 after I cycled the power. I thought, why it it now showing the altitude in feet, when before it was millibars? I realised though, that this was just coincidence and it is indeed reading 999 millibars where I am sitting, exactly the same as the number of feet!

OK, I have now discovered that both readings are in millibars. If you want to get the scoop on the Shearwater Pursuit Rebreather World is the place to go. Even for an open circuit diver it’s a very informative forum, Bruce, the CEO of Shearwater, is very active on it.

In setup, I’ve already set the GF99 feature, which shows the gradient at your current depth to allow you to work out a faster time to the surface. This number replaces the NDL when the computer goes into deco. So instead of using the gradient factor that is preset in the dive profile, you can exceed in whatever amount you desire to speed your way to the surface. I suppose you could also use it to be more conservative, selecting a lower gradient factor that the computer wants.

I’ll take my computer to the dive shop and give out upgrades to whoever needs one.



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