Vyper Questions

[DivingDoc]

Just bought a Vyper computer with console and while I haven't dived with it yet, I have been fiddling with the controls and the instruction manual. I am beginning to have some reservations and questions. Here they are:

In Nitrox mode, only the bar graph showing oxygen toxicity is displayed. Or rather, the bar graph that is the CBT graph in air mode becomes the Oxygen Limit Fraction bar graph in Nitrox mode. I am planning to take a Notrox certification course when I am in Cozumel later this month. Here's the question: Don't you have to also watch your nitrogen loading when you dive with Nitrox? It seems to me that both should be displayed.

The instruction manual advises you to leave it in nitrox mode if you are going to do both air and nitrox diving and just set it for 21% Oxygen pp. But if you do that, the bar graph will still be displaying O2 toxicity level, when you want it to display calculated Nitrogen tissue loading, right? Isn't this a problem?

The green/yellow/red stripe on the left is next to impossible to see at the surface in daylight. Is it any better under water?

The buttons are hard to press with my bare fingers. I should think they would be really difficult with neoprene gloves on.

When I turn off the light and turn the backlight on, I have two problems: 1) it's a rather faint backlight; and 2) the tissue loading and ascent bars (green/yellow/red) go black, so that it's impossible to see which zone you're in. Wouldn't this be a problem for night dives??

Just worried that I may have purchased the wrong computer. Any co

 

[DivingDoc]

Originally posted by DivingDoc
Just bought a Vyper computer with console and while I haven't dived with it yet, I have been fiddling with the controls and the instruction manual. I am beginning to have some reservations and questions. Here they are:

In Nitrox mode, only the bar graph showing oxygen toxicity is displayed. Or rather, the bar graph that is the CBT graph in air mode becomes the Oxygen Limit Fraction bar graph in Nitrox mode. I am planning to take a Notrox certification course when I am in Cozumel later this month. Here's the question: Don't you have to also watch your nitrogen loading when you dive with Nitrox? It seems to me that both should be displayed.

The instruction manual advises you to leave it in nitrox mode if you are going to do both air and nitrox diving and just set it for 21% Oxygen pp. But if you do that, the bar graph will still be displaying O2 toxicity level, when you want it to display calculated Nitrogen tissue loading, right? Isn't this a problem?

The green/yellow/red stripe on the left is next to impossible to see at the surface in daylight. Is it any better under water?

The buttons are hard to press with my bare fingers. I should think they would be really difficult with neoprene gloves on.

When I turn off the light and turn the backlight on, I have two problems: 1) it's a rather faint backlight; and 2) the tissue loading and ascent bars (green/yellow/red) go black, so that it's impossible to see which zone you're in. Wouldn't this be a problem for night dives??

Just worried that I may have purchased the wrong computer. Any co

Sorry -- didn't finish the last sentence there -- should be "any comments or insights woud be greatly appreciated.

 

[O-ring]

In Nitrox mode, only the bar graph showing oxygen toxicity is displayed. Or rather, the bar graph that is the CBT graph in air mode becomes the Oxygen Limit Fraction bar graph in Nitrox mode. I am planning to take a Notrox certification course when I am in Cozumel later this month. Here's the question: Don't you have to also watch your nitrogen loading when you dive with Nitrox? It seems to me that both should be displayed.

Although both are important, nitrogen loading isn't going to cause you to take a CNS hit and drown underwater. DCI symptoms are usually felt once the diver emerges from the water and do not generally cause drowning the way high oxygen exposure does. IMHO, that is probably why they chose to show the oxygen exposure graph when in Nitrox mode...when diving Nitrox you are diving an increased oxygen blend and are at more immediate risk from an oxygen hit than you are a nitrogen loading problem. Both would have been nice, but it may have been a choice of screen real estate and they chose to show the more pertinent graph in this situation.

The buttons are hard to press with my bare fingers. I should think they would be really difficult with neoprene gloves on.

I have not dove mine with gloves yet...I am a little worried about that too...

When I turn off the light and turn the backlight on, I have two problems: 1) it's a rather faint backlight; and 2) the tissue loading and ascent bars (green/yellow/red) go black, so that it's impossible to see which zone you're in. Wouldn't this be a problem for night dives??

Haven't done a night dive with it yet either, although I am doing a night dive in early July and will test it then...will let you know unless you do a night dive before then.

 

[DivingGal]

I've used mine at night and with "thick" gloves (along with reef gloves) and have had no problems.

 

[TexasMike]

Originally posted by DivingDoc
It seems to me that both should be displayed.

The instruction manual advises you to leave it in nitrox mode if you are going to do both air and nitrox diving and just set it for 21% Oxygen pp. But if you do that, the bar graph will still be displaying O2 toxicity level, when you want it to display calculated Nitrogen tissue loading, right? Isn't this a problem?

O-ring had some good answers there so I'll only add to the question that wasn't answered.

I also agree that it's good design to display both graphs. The N2 graph will help you keep up with staying within NDL's, but, as O-Ring said, when diving Nitrox, keeping up with your O2 exposure is the slightly more important statistic. The reason is that at the max of 1.6 ATA, there is a defined time limit you can be exposed to O2 before bad things start to happen (don't have my books here so I can't quote the exact figure, sorry ).

The reason for setting it at 21% is for a few reasons. First, remember that even sitting at your computer reading this message, you are breathing a nitrox mixture (21% oxygen, 78% nitrogen, 1% everything else). Next, from what I understand about the Vyper (and other brands/models) is that once and dove in nitrox mode, you're locked in that mode for 24 hours due to with the theory of your body requiring a period of off gassing (or desaturating) the additional O2 of the first dive. So since the computer is locked in nitrox from your first dive, and then you switch to standard air, you need to inform the computer that your "mix" is now 21% O2 versus the higher amount from the first dive.

The Vyper will continue to track your O2 exposure. And while on these "21%" dives, N2 is the governing limit, just pay close attention to the NDL time limit being displayed and remain ultra conservative with that time (IOW, don't wait until it shows :00 before moving to a shallower depth).

I hope that helped....and if any of the other folks spot an error in my statement of theory, please feel free to provide a correction.

 

[DivingDoc]

Originally posted by DivingGal
I've used mine at night and with "thick" gloves (along with reef gloves) and have had no problems.

Have you dove yours at night? Can you see the red/green/yellow markings with the backlight on?

 

[DivingGal]

Originally posted by DivingDoc


Have you dove yours at night? Can you see the red/green/yellow markings with the backlight on?

I believe so --- it was three months ago -- I'll have to check my logbook to see if I made any notes. That has been the only time I've used the Vyper at night since getting the computer.

I'll let you know once I've check the logbook. I know I don't have have problems seeing all the "bits and pieces" on the display.

 

[O-ring]

The instruction manual advises you to leave it in nitrox mode if you are going to do both air and nitrox diving and just set it for 21% Oxygen pp. But if you do that, the bar graph will still be displaying O2 toxicity level, when you want it to display calculated Nitrogen tissue loading, right? Isn't this a problem?

The reason it still displays o2 exposure is that when diving nitrox you must maintain a close watch on your total o2 exposure so you do not exceed 100% daily allowable exposure according to the DSAT tables.

It is still possible to exceed your daily allowable oxygen exposure on your repetitive dive using air, so I think the idea is to keep that graph there to continue informing you of your oxygen exposure. Like I said before, an oxygen hit is usually fatal at depth and, like TexasMike pointed out, that would make it the "more important" statistic.

They will cover all this in your nitrox class...

--Eric

 

[large_diver]

I have a Vyper and have made probably 8-10 night dives with it.

I wear thick 7mm gloves.

Can you press the buttons? Yes. The only button I press while underwater is the larger one that is located at 3 o'clock on the face (illumination button). I will admit, however, that I sometimes have to attempt to press it more than once to get the light to come on -- no doubt due to the gloves.

Can you see the face underwater at night using the illumination feature -- Yes. If there is a lot of other ambient light around, it is not particularly bright, especially if holding it at an angle, but you can certainly still read it. When I've made open water ascents/ descents, I usually clip off my primary light. When I do this (now my light is down and away from the computer), the display is plenty bright. Ascending is really the only time I use the illimunation feature -- I can usually see the display just fine if it is on the edge of my light beam (not well-visible if you shine the light directly at the face).

Can you see the ascent speed indicators in the dark using the illiumination feature -- Yes. I was on a night dive about 10 days ago and made an OW ascent from 35 feet. I have the illimination set to 30 seconds just for occasions like this, so I can watch the ascent indicator while coming up. I know you can see the indicators because at one point I was coming up a little fast. Just so there is no confusion, I'm talking about the ascent rate indicators on the right side of the screen.

Hope this helps.

 

[DivingDoc]

Originally posted by large_diver
I have a Vyper and have made probably 8-10 night dives with it.

I wear thick 7mm gloves.

Can you press the buttons? Yes. The only button I press while underwater is the larger one that is located at 3 o'clock on the face (illumination button). I will admit, however, that I sometimes have to attempt to press it more than once to get the light to come on -- no doubt due to the gloves.

The manual says that you need to press the button for 2 seconds to turn on the backlight.

Can you see the face underwater at night using the illumination feature -- Yes. If there is a lot of other ambient light around, it is not particularly bright, especially if holding it at an angle, but you can certainly still read it. When I've made open water ascents/ descents, I usually clip off my primary light. When I do this (now my light is down and away from the computer), the display is plenty bright. Ascending is really the only time I use the illimunation feature -- I can usually see the display just fine if it is on the edge of my light beam (not well-visible if you shine the light directly at the face).[/B]

But can you see the green/yellow/red markings along the left hand edge with the light on? When I turn the light on at home at night with the room lights off, that bar graph is sillhouetted against the light and is therefore black and unreadable. Is that the case during a night dive or not?

Can you see the ascent speed indicators in the dark using the illiumination feature -- Yes. I was on a night dive about 10 days ago and made an OW ascent from 35 feet. I have the illimination set to 30 seconds just for occasions like this, so I can watch the ascent indicator while coming up. I know you can see the indicators because at one point I was coming up a little fast. Just so there is no confusion, I'm talking about the ascent rate indicators on the right side of the screen.
[/B]

You can see the little pixels that go up, but can you see where they are relative to the green/yellow/red zones on the right hand edge of the screen? It doesn't help to see little pixels if you don't know if you are in the green, yellow or red zone.