Ratio Deco v Computers

Leigh u · December 24th, 2005, 10:27 PM

I would put more trust in tables and diving the profile, rather than trust a piece of crap around my wrist. I understand that you are not DIR, but if you dive standard gasses deco calculation is a breeze.

When we get into using only a computer, that is where, in the non DIR world, you would use a second back up computer..as one has no clue where they are with tissue loading...and now we must let another computer tell us what it thinks is a good profile.

If you already have tables cut, then 5 minutes either way isn't a huge deal.

Following a computer makes it a pain in the ass to dive with a buddy..who's computer to follow and does the buddy folllow the team leader's profile ? ...and does that mean buddy teams must have the same computer ?..it gets a bit sillly from there.

If I was going for a computer the VR3 would be my choice so I could play games on it after I pull it out of my pocket at the end of the dive.

daz · December 24th, 2005, 10:48 PM

Quote: (Originally Posted by Leigh u)

I would put more trust in tables and diving the profile, rather than trust a piece of crap around my wrist.

Just an observation, What do you use to cut tables? A piece of crap on a desktop?

What do you use to follow a profile? Another piece of electronic crap I'd guess?

Sorry I don't mean to be flippant or confrontational and I agree that following computers blindly is not the wisest choice but just dismissing them as a piece of crap is not a very winning argument.

They are mearly a tool, a means of providing information. It is up to the user to interprete the information provided and make an informed decision.

Daz

*Clare Gledhill* · December 24th, 2005, 11:06 PM

Quote: (Originally Posted by daz)

just dismissing them as a piece of crap is not a very winning argument. They are mearly a tool, a means of providing information. It is up to the user to interprete the information provided and make an informed decision.

Yup. But then Leigh did go on to say...

Quote:

When we get into using only a computer

(emphasis added by me)

... and this does make more sense doesn't it. All the advice on this thread has been built on the principle that we need to understand our diving not blindly follow something which may fail when we need it most.

I was on a dive recently with two members of this board when BOTH of their computers failed. Chance of that on one dive eh? Wasn't a deep dive with mandatory deco but even if it had been it didn't matter really, we still had one working depth gauge in the team and everything can run from that.

GUE will always tell you to dive within your training - regardless of your agency - it is exactly this advice which one leaves DIR F with. So get the training, find a way of diving that you are comfortable with and have fun.

Leigh u · December 24th, 2005, 11:25 PM

no problem...piece of crap meaning it can fail under water. It seemed that the poster admitted that following a computer is the way to go..so that also means there is no concrete dive plan..and if there was a plan..it would make sense to dive tables anyway.

They are a tool and that is fine..but the people who say they need them so much usually jump in the water and overstay their plan and have no real idea of where they are deco wise and possibly gas wise

A home computer spits out profiles..but if it breaks..you can drive to the shop and buy a new one without doing much deco

The computer isn't the piece of crap..the piece of crap is ones brain for relying on it.

It's good to talk about these things for sure

Little Pete · December 24th, 2005, 11:51 PM

I just got my new copy of Undersea Journal today and it had several references to making new divers buy computers and use them. The implication was that it was the best way to do things and didn't require understanding of the tables really.....to each their own.

I did smirk at their doing a feature on 'Into the Big Blue' saying about how great it was for promoting scuba diving.......then seeing all the cast in Halcyon gear....t'was top notch :D

daz · December 25th, 2005, 01:11 AM

Hi my names Daz and I'm playing devil's advocate :D

As I said I'm not trying to provoke an argument but what I do want to provoke is an explaination of the problem with computers and what the alternatives are.

I realise that I might just come across as somewhat confrontational (and I'm sure it won't be the last time

) but rest assured there is usually a genuine reason behind my comments.

I could of course just be direct and ask "What is wrong with computers? Why do you think they are a piece of crap" but then the response is likely to be focussed solely on the question and does not provoke a wider discussion IMHO.

Leigh's subsequent response actually addressed a couple of the questions I would want answered if I were asking about computers and the pros and cons, he has explained why cutting tables at home is not such a problem although he did miss a chance to respond about electronic depth dive timers not causing the same problem (Team diving and all that :D).

I think the point I am trying to make probably deserves a seperate thread as it's much wider than just discussing the DIR view on computers so rather than go off at a tangent I'll start a new thread.

Incidently the point about people just leaping in with blind faith in their computers and a total disregard for up front gas planning, deco obligations... Unfortunately this is all too common

Daz

P.S It's gone midnight... HAPPY CHRISTMAS :D

Leigh u · December 25th, 2005, 02:15 AM

Quote: (Originally Posted by daz)

Hi my names Daz and I'm playing devil's advocate :D

As I said I'm not trying to provoke an argument but what I do want to provoke is an explaination of the problem with computers and what the alternatives are.

I realise that I might just come across as somewhat confrontational (and I'm sure it won't be the last time

) but rest assured there is usually a genuine reason behind my comments.

I could of course just be direct and ask "What is wrong with computers? Why do you think they are a piece of crap" but then the response is likely to be focussed solely on the question and does not provoke a wider discussion IMHO.

Leigh's subsequent response actually addressed a couple of the questions I would want answered if I were asking about computers and the pros and cons, he has explained why cutting tables at home is not such a problem although he did miss a chance to respond about electronic depth dive timers not causing the same problem (Team diving and all that :D).

I think the point I am trying to make probably deserves a seperate thread as it's much wider than just discussing the DIR view on computers so rather than go off at a tangent I'll start a new thread.

Incidently the point about people just leaping in with blind faith in their computers and a total disregard for up front gas planning, deco obligations... Unfortunately this is all too common

Daz

P.S It's gone midnight... HAPPY CHRISTMAS :D

The bonus on bottom timers is..if they fail..your buddies is the same..give or take a few feet..if you lose your computer profile and you were running the deco..your buddy now has to run deco .......anyway..we all get the point.
DIR divers don't have worry about it..because we are taught THE FUNDAMENTALS..plan the dive and dive the plan...and if we do have to deviate..we can adjust without having to pull out tables..

This approach isn't for everyone..but I just hate hearing people say they don't like DIR because they want to use a computer...fixating on something they heard or read.

Unfortunately people I have met seem to use a computer to maximize bottom time and nothing else.

I know so many non DIR divers that don't use a computer either..it seems to work for them.

IF this thread would have started in a NON DIR forum..I promise I would not have posted

and Happy Christmas to everyone..let's hope Santa buys everyone a computer in gauge mode

...

daz · December 25th, 2005, 02:29 AM

Quote: (Originally Posted by Leigh u)

IF this thread would have started in a NON DIR forum..I promise I would not have posted

That's a real shame but I think I understand why

Remember just because someone disagrees, doesn't mean you are wrong :D (Advice I live by

)

Daz

Leigh u · December 25th, 2005, 02:46 AM

I don't think I have ever been quite right LOL

Mark Chase · December 25th, 2005, 05:04 AM

Hi M8 not picking on you at all but you raised some good points of discussion to bounce off.

Quote:

The bonus on bottom timers is..if they fail..your buddies is the same..give or take a few feet..if you lose your computer profile and you were running the deco..your buddy now has to run deco .......anyway..we all get the point.

Using a computer for deco with a buddy you run with the most Conservative profile. When my stop clears i check with my buddy if his stop hasn't cleared yet we wait. Simple.

If my computer breaks I follow his and vice versa.

Quote:

DIR divers don't have worry about it..because we are taught THE FUNDAMENTALS..plan the dive and dive the plan...and if we do have to deviate..we can adjust without having to pull out tables..

Admirable but limiting. The confines within which the DOTF system works dictate the dive. This is fine as long as you don't mind the confines. Tables are similar. I dived tables for years but I just hated the way they dictated what to do all the time. :D A full decompression and look ahead gas switching computer like the VR3 takes away the restrictions and lets you do the dive on the fly instead :D

Quote:

This approach isn't for everyone..but I just hate hearing people say they don't like DIR because they want to use a computer...fixating on something they heard or read.

Its one of the reasons I wouldn't do deep diving within the DIR system.

Quote:

Unfortunately people I have met seem to use a computer to maximize bottom time and nothing else.

Why is this bad? Every dive I have ever planned where water temperature & tide were not an issue has been planned to maximize the bottom time. Thats what I am on the boat for. To dive the wreck. If i can figure out a way to spend an extra 10mins on the wreck I will regardless of using tables or a computer.

Quote:

I know so many non DIR divers that don't use a computer either..it seems to work for them.

I know quite a few but they are a getting fewer and fewer

Quote:

IF this thread would have started in a NON DIR forum..I promise I would not have posted

I know the feeling :D

People give the wrong reasons for not using a computer. They usually say, they might break. Well thats true but if its a full look ahead deco computer you knew your deco commitment within 5mins of it breaking so you have a pretty good idea how much deco you have to do. Also unless your an idiot you will have a buddy or a back up computer. For gas planning you would have had to pre plan the dive so you have a pretty good idea how much deco you need any way so its just a case of guesstimating the stops from there.

Your guesstimate would of course be based on depth and total deco commitment using the basic rules of first stop at max depth - 2ATA and last stop being 50% of total deco

Using this sort of deco is not advisable for day to day diving but if the crap has hit the fan it will get you out of the water. Lets face it you can extend the shallow stops until your deco gas runs out if your concerned.

The second argument is I wouldn't trust a computer to calculate my deco.. Well thats just hilarious as of course we all do. To ensure the one on your wrist is working you can use you pre planning visual image of the deco or your buddies computer. If i am doing 45 @ 60 and my computer say's time to surface 45mins I know instantly its talking rubbish. I would check with my buddy and if his said 45mins as well (pretty unlikely) we would do a manual deco because we already knew we were expecting apx 100mins of deco.

So the reliability issues are not particularly relevant. The only computer failure i have ever had in the water was with a Vytec and it failed because the depth sensor packed up. At 100m it said I was at 116 and at 6m it said I was on the surface. It was in gage mode. Having your depth gage reading a mile out would be interesting even for DOTF :D. Fortunately my two VR3s worked fine and gave me accurate depth readings that concurred with my buddies VR3.

Depth sensors are fragile and fail more often than any other component in dive computers. Just drop the computer and it can be game over for the sensor.

No there is one damed good reason not to use computers and one reason only. They are expensive. My two CCR Trimix VR3s would set you back £800+ each. So I payed (by todays costs) £1600 to be able to do what DOTF & table diving can do (within limits) using a £200 depth gage and timer.

Do I regret it? Not on your life. I love the freedom it brings to my diving.

However if the VR3 was not available i would probably opt for DOTF rather than tables. On dives less than 50m I use DOTF as mental back up to my computers if I am solo. I only use it as a rough guide and I pad it out but it is handy to know.

Quote:

and Happy Christmas to everyone..let's hope Santa buys everyone a computer in gauge mode

Or even better a VPM bassed VR3 :D

ATB

Mark Chase

December 24th, 2005, 11:06 PM	#3 (permalink)
Clare Gledhill(Offline) GUE Instructor Site Admin Join Date: Nov 2005 Location: UK Posts: 1,540	Quote: (Originally Posted by daz) just dismissing them as a piece of crap is not a very winning argument. They are mearly a tool, a means of providing information. It is up to the user to interprete the information provided and make an informed decision. Yup. But then Leigh did go on to say... Quote: When we get into using only a computer (emphasis added by me) ... and this does make more sense doesn't it. All the advice on this thread has been built on the principle that we need to understand our diving not blindly follow something which may fail when we need it most. I was on a dive recently with two members of this board when BOTH of their computers failed. Chance of that on one dive eh? Wasn't a deep dive with mandatory deco but even if it had been it didn't matter really, we still had one working depth gauge in the team and everything can run from that. GUE will always tell you to dive within your training - regardless of your agency - it is exactly this advice which one leaves DIR F with. So get the training, find a way of diving that you are comfortable with and have fun. __________________ Clare . "Keep away from people who try to belittle your ambitions....Small people always do that, but the really great make you feel that you too can become great." Interested in DIR dive training? Always happy to chat/answer questions so get in touch via PM or visit www.dirdiver.co.uk

December 25th, 2005, 01:11 AM	#6 (permalink)
daz(Offline) "Don't worry I'm approved" Join Date: Nov 2005 Location: Bristol Posts: 209	Hi my names Daz and I'm playing devil's advocate :D As I said I'm not trying to provoke an argument but what I do want to provoke is an explaination of the problem with computers and what the alternatives are. I realise that I might just come across as somewhat confrontational (and I'm sure it won't be the last time ) but rest assured there is usually a genuine reason behind my comments. I could of course just be direct and ask "What is wrong with computers? Why do you think they are a piece of crap" but then the response is likely to be focussed solely on the question and does not provoke a wider discussion IMHO. Leigh's subsequent response actually addressed a couple of the questions I would want answered if I were asking about computers and the pros and cons, he has explained why cutting tables at home is not such a problem although he did miss a chance to respond about electronic depth dive timers not causing the same problem (Team diving and all that :D). I think the point I am trying to make probably deserves a seperate thread as it's much wider than just discussing the DIR view on computers so rather than go off at a tangent I'll start a new thread. Incidently the point about people just leaping in with blind faith in their computers and a total disregard for up front gas planning, deco obligations... Unfortunately this is all too common Daz P.S It's gone midnight... HAPPY CHRISTMAS :D Last edited by daz; December 25th, 2005 at 01:15 AM.

December 24th, 2005, 10:27 PM	#1 (permalink)
Leigh u(Offline) We Go Down Join Date: Nov 2005 Location: Ottawa Canada Posts: 227	I would put more trust in tables and diving the profile, rather than trust a piece of crap around my wrist. I understand that you are not DIR, but if you dive standard gasses deco calculation is a breeze. When we get into using only a computer, that is where, in the non DIR world, you would use a second back up computer..as one has no clue where they are with tissue loading...and now we must let another computer tell us what it thinks is a good profile. If you already have tables cut, then 5 minutes either way isn't a huge deal. Following a computer makes it a pain in the ass to dive with a buddy..who's computer to follow and does the buddy folllow the team leader's profile ? ...and does that mean buddy teams must have the same computer ?..it gets a bit sillly from there. If I was going for a computer the VR3 would be my choice so I could play games on it after I pull it out of my pocket at the end of the dive.

December 24th, 2005, 10:48 PM	#2 (permalink)
daz(Offline) "Don't worry I'm approved" Join Date: Nov 2005 Location: Bristol Posts: 209	Quote: (Originally Posted by Leigh u) I would put more trust in tables and diving the profile, rather than trust a piece of crap around my wrist. Just an observation, What do you use to cut tables? A piece of crap on a desktop? What do you use to follow a profile? Another piece of electronic crap I'd guess? Sorry I don't mean to be flippant or confrontational and I agree that following computers blindly is not the wisest choice but just dismissing them as a piece of crap is not a very winning argument. They are mearly a tool, a means of providing information. It is up to the user to interprete the information provided and make an informed decision. Daz

December 24th, 2005, 11:25 PM	#4 (permalink)
Leigh u(Offline) We Go Down Join Date: Nov 2005 Location: Ottawa Canada Posts: 227	no problem...piece of crap meaning it can fail under water. It seemed that the poster admitted that following a computer is the way to go..so that also means there is no concrete dive plan..and if there was a plan..it would make sense to dive tables anyway. They are a tool and that is fine..but the people who say they need them so much usually jump in the water and overstay their plan and have no real idea of where they are deco wise and possibly gas wise A home computer spits out profiles..but if it breaks..you can drive to the shop and buy a new one without doing much deco The computer isn't the piece of crap..the piece of crap is ones brain for relying on it. It's good to talk about these things for sure

December 24th, 2005, 11:51 PM	#5 (permalink)
Little Pete(Offline) New Member Join Date: Nov 2005 Location: UK Posts: 509	I just got my new copy of Undersea Journal today and it had several references to making new divers buy computers and use them. The implication was that it was the best way to do things and didn't require understanding of the tables really.....to each their own. I did smirk at their doing a feature on 'Into the Big Blue' saying about how great it was for promoting scuba diving.......then seeing all the cast in Halcyon gear....t'was top notch :D

December 25th, 2005, 02:15 AM	#7 (permalink)
Leigh u(Offline) We Go Down Join Date: Nov 2005 Location: Ottawa Canada Posts: 227	Quote: (Originally Posted by daz) Hi my names Daz and I'm playing devil's advocate :D As I said I'm not trying to provoke an argument but what I do want to provoke is an explaination of the problem with computers and what the alternatives are. I realise that I might just come across as somewhat confrontational (and I'm sure it won't be the last time ) but rest assured there is usually a genuine reason behind my comments. I could of course just be direct and ask "What is wrong with computers? Why do you think they are a piece of crap" but then the response is likely to be focussed solely on the question and does not provoke a wider discussion IMHO. Leigh's subsequent response actually addressed a couple of the questions I would want answered if I were asking about computers and the pros and cons, he has explained why cutting tables at home is not such a problem although he did miss a chance to respond about electronic depth dive timers not causing the same problem (Team diving and all that :D). I think the point I am trying to make probably deserves a seperate thread as it's much wider than just discussing the DIR view on computers so rather than go off at a tangent I'll start a new thread. Incidently the point about people just leaping in with blind faith in their computers and a total disregard for up front gas planning, deco obligations... Unfortunately this is all too common Daz P.S It's gone midnight... HAPPY CHRISTMAS :D The bonus on bottom timers is..if they fail..your buddies is the same..give or take a few feet..if you lose your computer profile and you were running the deco..your buddy now has to run deco .......anyway..we all get the point. DIR divers don't have worry about it..because we are taught THE FUNDAMENTALS..plan the dive and dive the plan...and if we do have to deviate..we can adjust without having to pull out tables.. This approach isn't for everyone..but I just hate hearing people say they don't like DIR because they want to use a computer...fixating on something they heard or read. Unfortunately people I have met seem to use a computer to maximize bottom time and nothing else. I know so many non DIR divers that don't use a computer either..it seems to work for them. IF this thread would have started in a NON DIR forum..I promise I would not have posted and Happy Christmas to everyone..let's hope Santa buys everyone a computer in gauge mode ...

December 25th, 2005, 02:29 AM	#8 (permalink)
daz(Offline) "Don't worry I'm approved" Join Date: Nov 2005 Location: Bristol Posts: 209	Quote: (Originally Posted by Leigh u) IF this thread would have started in a NON DIR forum..I promise I would not have posted That's a real shame but I think I understand why Remember just because someone disagrees, doesn't mean you are wrong :D (Advice I live by ) Daz

December 25th, 2005, 02:46 AM	#9 (permalink)
Leigh u(Offline) We Go Down Join Date: Nov 2005 Location: Ottawa Canada Posts: 227	I don't think I have ever been quite right LOL

December 25th, 2005, 05:04 AM	#10 (permalink)
Mark Chase(Offline) New Member Join Date: Nov 2005 Location: Kent England Posts: 905	Hi M8 not picking on you at all but you raised some good points of discussion to bounce off. Quote: The bonus on bottom timers is..if they fail..your buddies is the same..give or take a few feet..if you lose your computer profile and you were running the deco..your buddy now has to run deco .......anyway..we all get the point. Using a computer for deco with a buddy you run with the most Conservative profile. When my stop clears i check with my buddy if his stop hasn't cleared yet we wait. Simple. If my computer breaks I follow his and vice versa. Quote: DIR divers don't have worry about it..because we are taught THE FUNDAMENTALS..plan the dive and dive the plan...and if we do have to deviate..we can adjust without having to pull out tables.. Admirable but limiting. The confines within which the DOTF system works dictate the dive. This is fine as long as you don't mind the confines. Tables are similar. I dived tables for years but I just hated the way they dictated what to do all the time. :D A full decompression and look ahead gas switching computer like the VR3 takes away the restrictions and lets you do the dive on the fly instead :D Quote: This approach isn't for everyone..but I just hate hearing people say they don't like DIR because they want to use a computer...fixating on something they heard or read. Its one of the reasons I wouldn't do deep diving within the DIR system. Quote: Unfortunately people I have met seem to use a computer to maximize bottom time and nothing else. Why is this bad? Every dive I have ever planned where water temperature & tide were not an issue has been planned to maximize the bottom time. Thats what I am on the boat for. To dive the wreck. If i can figure out a way to spend an extra 10mins on the wreck I will regardless of using tables or a computer. Quote: I know so many non DIR divers that don't use a computer either..it seems to work for them. I know quite a few but they are a getting fewer and fewer Quote: IF this thread would have started in a NON DIR forum..I promise I would not have posted I know the feeling :D People give the wrong reasons for not using a computer. They usually say, they might break. Well thats true but if its a full look ahead deco computer you knew your deco commitment within 5mins of it breaking so you have a pretty good idea how much deco you have to do. Also unless your an idiot you will have a buddy or a back up computer. For gas planning you would have had to pre plan the dive so you have a pretty good idea how much deco you need any way so its just a case of guesstimating the stops from there. Your guesstimate would of course be based on depth and total deco commitment using the basic rules of first stop at max depth - 2ATA and last stop being 50% of total deco Using this sort of deco is not advisable for day to day diving but if the crap has hit the fan it will get you out of the water. Lets face it you can extend the shallow stops until your deco gas runs out if your concerned. The second argument is I wouldn't trust a computer to calculate my deco.. Well thats just hilarious as of course we all do. To ensure the one on your wrist is working you can use you pre planning visual image of the deco or your buddies computer. If i am doing 45 @ 60 and my computer say's time to surface 45mins I know instantly its talking rubbish. I would check with my buddy and if his said 45mins as well (pretty unlikely) we would do a manual deco because we already knew we were expecting apx 100mins of deco. So the reliability issues are not particularly relevant. The only computer failure i have ever had in the water was with a Vytec and it failed because the depth sensor packed up. At 100m it said I was at 116 and at 6m it said I was on the surface. It was in gage mode. Having your depth gage reading a mile out would be interesting even for DOTF :D. Fortunately my two VR3s worked fine and gave me accurate depth readings that concurred with my buddies VR3. Depth sensors are fragile and fail more often than any other component in dive computers. Just drop the computer and it can be game over for the sensor. No there is one damed good reason not to use computers and one reason only. They are expensive. My two CCR Trimix VR3s would set you back £800+ each. So I payed (by todays costs) £1600 to be able to do what DOTF & table diving can do (within limits) using a £200 depth gage and timer. Do I regret it? Not on your life. I love the freedom it brings to my diving. However if the VR3 was not available i would probably opt for DOTF rather than tables. On dives less than 50m I use DOTF as mental back up to my computers if I am solo. I only use it as a rough guide and I pad it out but it is handy to know. Quote: and Happy Christmas to everyone..let's hope Santa buys everyone a computer in gauge mode Or even better a VPM bassed VR3 :D ATB Mark Chase