Questions about Diving Computers.

[O_Cranston]

Hey guys,
This Christmas i got the Sherwood Amphos Diving Computer, and i have a few questions about it and diving computers in general. BTW i have only been Scuba certified for less than a year so i might have some simple/stupid questions.

Questions:

1. When i am going to get ready for a dive i will have to set the F02 (right?), my problem is i don't know what to set my F02 level to. Should i set it so it is has a max depth of 60ft or should i do something else?

2. When i am setting alarms for my dive one is the alarm for the Elapsed Dive Time. When i am setting it why can it only go up to 3:00 minutes? Why can't it go higher?

3. Another alarm i have to set is the NIBG (Nitrogen Bar Graph), when i set this does it warn me when i have too much nitrogen in my body. How do i know what level i should set the alarm to?

4. The final alarm i have to set it the Dive Time Remaining, and i was wondering why i can only go up to 20 minutes?

5. P02- what is it? What do i need to set it to?

6. Final question: Could i get someone to clear up Deep Stops and when and when i don't have to take decompression stop when ascending?

If someone could answer these that would help me soo much. (As well save me the embarrassment of asking someone in person.)

 

[Dr. Lecter]

1. When i am going to get ready for a dive i will have to set the F02 (right?), my problem is i don't know what to set my F02 level to. Should i set it so it is has a max depth of 60ft or should i do something else?

5. P02- what is it? What do i need to set it to?

6. Final question: Could i get someone to clear up Deep Stops and when and when i don't have to take decompression stop when ascending?

Go find whoever certified you as competent to dive and demand your money back.

 

[oly5050user]

Go find whoever certified you as competent to dive and demand your money back.

kind of a way harsh reply Dr Lecter....o cranston; read the manual..alot of the questions you have appear to be for nitrox..If you are not certied for nitrox do not bother with the settings. Get certified for nitrox and ask the instructor to explain these settings to you.

 

[Dr. Lecter]

kind of a way harsh reply Dr Lecter....o cranston; read the manual..alot of the questions you have appear to be for nitrox..If you are not certied for nitrox do not bother with the settings. Get certified for nitrox and ask the instructor to explain these settings to you.

It is indeed, but not understanding anything about fO2, pO2, or when deco stops might be necessary could get him bent and/or dead and should have been covered in OW.

 

[drrich2]

F02 refers to the percentage of oxygen in your breathing gas. Regular air is 21%. You probably are not nitrox certified. Nitrox is a specially made nitrogen & oxygen mix that usually has an oxygen % different from air, which can have a range of uses, such as extending bottom time.

Your computer lets you set FO2 so that you can tell the computer when you are using nitrox. I am not familiar with your computer. I'm guessing that it will have a default of 'Air,' or FO2 21%. Check your manual and be sure.

Because of the risk of toxicity when diving with nitrox that has a higher O2 percentage than room air, a given nitrox mix will have a MOD - maximum operating depth. A very common nitrox (a.k.a. Enriched Air Nitrox, or EAN) is 32% oxygen (EAN 32). The MOD for it is 110 feet, whereas a person with proper training and preparation can dive 130 feet on air (as that's the recommended recreational diving limit).

If you set FO2 on your computer to achieve a MOD of 60 feet (which I'm guessing is what you're talking about doing), your computer will think you are diving a very low nitrogen, high oxygen mix. That would give excessive no-decompression time limits that could lead to you diving far too long at depth (if your air consumption is good and you can stay down awhile).

I assume you are just doing no-decompression recreational dives. In that case, if you dive within no-decompression limits, ascend at a proper rate, observe the 3 minute 15 foot safety stop, allow for property surface intervals and don't do excessive repetitive diving, you shouldn't get 'too much' nitrogen in your body. An alarm in that regard is to let you know you're getting close, so you will stop and think through what you're doing before you run out of NDL.

Then again, if you're diving long, deep &/or repetitively that you're in danger of exceeding NDLs, pay attention. The alarm should be a fall-back you never need.


Richard.

 

[NAM001]

I can only assume that by your questions taht you are not certified for NTROX

1. FO2 is the O2 content of the gas you are breathing air or ie 32% settings should go from 21-40 or 50.
2. I would think that the 3:00 is 3 hours not minutes another, i guess, nitrox arena setting. others can explain it better.
3. I think that this is an on or off alarm. should tell you that you are near your or exceeding your NDL
4. The Dive time remaining is an alarm that will let you know you are in your final minutes of the dive. You know it will take you 8 min to get to surface so you set
it at 10 to tell you to finish what you are doing and start your ascent.
5. PO2 is another nitrox value normally. you normally do not set moere than 1.4 atm. for air that will allow a depth of 160ft +/- MOOT for an ow diver.
6. This question scares me because unlike the others this is not primarily a NITROX issue but a basic ow level item. The idea is that if you are at say 100 ft and you ascend you stop at say 50 ft for a couple of minutes to allow the off gassing to catch up with your ascent, and then continue to your safety stop. As an ow you do not EXCEED NDL and therefore do not do formal DECOMPRESSION STOPS. As an ow your depth is 60 ft max and as such deep stops can not apply to that dive perofile. Some will argue this point.

I think i have to agree with some that these things proably should have been discussed in your ow training.

The answers are offered without the benifit of knowing your specific computer.

Hey guys,
This Christmas i got the Sherwood Amphos Diving Computer, and i have a few questions about it and diving computers in general. BTW i have only been Scuba certified for less than a year so i might have some simple/stupid questions.

Questions:

1. When i am going to get ready for a dive i will have to set the F02 (right?), my problem is i don't know what to set my F02 level to. Should i set it so it is has a max depth of 60ft or should i do something else?

2. When i am setting alarms for my dive one is the alarm for the Elapsed Dive Time. When i am setting it why can it only go up to 3:00 minutes? Why can't it go higher?

3. Another alarm i have to set is the NIBG (Nitrogen Bar Graph), when i set this does it warn me when i have too much nitrogen in my body. How do i know what level i should set the alarm to?

4. The final alarm i have to set it the Dive Time Remaining, and i was wondering why i can only go up to 20 minutes?

5. P02- what is it? What do i need to set it to?

6. Final question: Could i get someone to clear up Deep Stops and when and when i don't have to take decompression stop when ascending?

If someone could answer these that would help me soo much. (As well save me the embarrassment of asking someone in person.)

 

[O_Cranston]

Thanks for all the responses! After reading through your comments and through one of my PADI books i got all the answers.

 

[Mr Carcharodon]

It is always good to get clarification when needed.

1. When i am going to get ready for a dive i will have to set the F02 (right?), my problem is i don't know what to set my F02 level to. Should i set it so it is has a max depth of 60ft or should i do something else?
Set your computer to the FO2 you are diving. That will be 0.21 for air.

2. When i am setting alarms for my dive one is the alarm for the Elapsed Dive Time. When i am setting it why can it only go up to 3:00 minutes? Why can't it go higher?
Given the lack of context beats me! In general it is best to turn most of the alarms off since they will fall somewhere between annoying and useless.

3. Another alarm i have to set is the NIBG (Nitrogen Bar Graph), when i set this does it warn me when i have too much nitrogen in my body. How do i know what level i should set the alarm to?

You never have too much nitrogen in your body, only too little gas to get it back out again. That sounds like a bar graph set to maximum allowable pressure values (m-values) or some percentage of that. I'd read the manual on that one but do not go over 100%.

4. The final alarm i have to set it the Dive Time Remaining, and i was wondering why i can only go up to 20 minutes?
Sounds like an alarm linked to gas supply or NDL. Both are fairly useless if they are linked to depth. For example if you computer alarms to tell you you only have 20 minutes left of NDL time at 100 fsw the alarm will go off when you first arrive there. That might be marginally useful if you have no idea (hopefully not the case) but if you are planning to spend 10 minutes at 100 fsw and then the last half of your dive between 30 fsw an the surface it is not useful at all.

5. P02- what is it? What do i need to set it to?
This is probably the max ppO2 alarm. Most people use 1.4 ATA however 1.2 ATA is more conservative and used by some groups. Others still use 1.6 ATA but I do not recommend that unless you really understand what you are doing. Again read the manual. In practice if you are diving air to 60 fsw max this is a non-issue.

6. Final question: Could i get someone to clear up Deep Stops and when and when i don't have to take decompression stop when ascending?
Make it a habit of spending 1 minute at half max depth and 1 minute at each of 30, 20 and 10 fsw followed by a slow ascent to the surface. Double those times if you have done a lot of work during the dive or are cold or stressed. If you go below 30 fsw for more than a few minutes take stops unless there is a compelling reason not to. That said paying attention to your gas supply is much more important.

 

[oly5050user]

It is indeed, but not understanding anything about fO2, pO2, or when deco stops might be necessary could get him bent and/or dead and should have been covered in OW.

the guy is recently ow certified..There is nothing in a ow course that has to do with fO2, pO2 ..that is only in a nitrox course.....he was taught recreational no decompression diving..Only safety stops and minimal emergency deco is to be gone over.

 

[Jim Lapenta]

No it's not. Those are covered and discussed in some agencies OW courses. Not to the extent as in a Nitrox course but we do talk about F02 and P02 and what they mean in relation to using air. And our deco discussion involves using the US Navy air deco tables. Not to plan deco but as a supplement to RMV and SAC discussion and how exceeding the NDL's could mean you do not have enough gas for the required decompression stop.

As for the OP and his questions I agree that reading the manual will help and it looks like the manual for it that you can find on the dive computer wizard site is pretty good. Not like some of the others I have seen and since you can download it it's easy to read instead of that little tiny one that often comes with a computer. It's here http://www.dive-computer-wizard.com/manuals/Sherwood_Amphos_dive_computer.pdf

A better bet is to go to the Ediver website and take an on line course specific to his computer if they have one.

It does not appear they do however but this may help from scuba . com Sherwood Amphos Air / Nitrox Wrist Computer Dive Watch Video Review - YouTube Nice little overview but agree that if he's using a computer that does nitrox he should understand those functions and does not need to be nitrox certified to do that. I agree that much of that is OW class information.

Sherwood is also a pelagic company as far as computers go so their may be something else in another brand that works the same way. But what he really needs to do is go have the shop it was purchased from show him how to use all the features. If it were me I would not even charge him for that.