Convince me to get a bottom timer...

[Bismark]

Bottom timers are less expensive than most computers and tend to be more reliable. Some people like to use computers in gauge mode, but that is overkill in my opinion. If you want a backup timing device, get a high quality underwater watch - Casio G-Shock, Citizen Hyper Aqualand, or something similar.

Good luck with your class, and let us know how it turns out.

FWIW, Of our group, the majority use computers in gauge mode and the majority of them use the Tec 2G. Tough to beat the advantage of having a stopwatch feature with seconds.

 

[Bismark]

First off, DIR or otherwise, there's a distinction to be made between using a dive computer and relying on a dive computer. There's nothing wrong with the former ... but the latter is definitely NOT DIR (or even wise, to my concern).

Information is only as good as your brain's ability to process it. If you understand the basics of the dive plan, then the information on the computer only serves to help you make the right decisions. Using the computer to determine your dive plan indicates that you lack an understanding of the basics ... and therefore maybe you should reconsider your qualifications to do that type of dive.

When I started tech diving, I purchased a DR Nitek HE. I quickly discovered something important ... the computer really didn't want to allow me to do the type of dive I wanted to do. It didn't like helium (fancy that, for a computer designed for trimix), and it used a strict Buhlmann algorithm that didn't like deep stops. In effect, it wanted a "bend and mend" profile. If I did the dive I wanted to do, using the basic rules of RD to shape my profile, I would bend the computer every time. After causing some confusion with the team trying to keep the computer happy, I decided to sell it and switch to a bottom timer.

Over time I got more comfortable with what I was doing. So I got a replacement computer (Tech2G) and put it in gauge mode. It's got a couple of features I found handy ... most notably a resettable seconds counter that made timing deco stops simpler. I don't need it ... I can time my stops perfectly well with the Uwatec BT ... but it's a nice-to-have. Bottom line ... don't learn to rely on it. Use it as a convenience. You STILL have to understand your schedule, and why you chose the ascent profile you did. And you STILL have to be on the same page as everyone else on the team.

I've since replaced my "backup" BT with an X1 (no ... I'm NOT joking). Why? Because I dive in some really dark places (Lake Washington at 200 feet redefines the term ... my 18W HID often fades to nothing after about 4 or 5 feet) and I like the display. In fact, so do my dive buddies. And, given the expense of tech diving in general, the cost of an X1 really isn't all that outrageous. And I LIKE being able to compare my RD schedule to what the X1's V-Planner program is displaying. No, I don't rely on the X1 to determine my profile ... I use the schedule the team agreed to before the dive. But a "sanity check" is nice. Most times, V-Planner clears the dive well before our 20-foot stop is done. Great. Every once in a while, it's off by a minute or two, and I "bend" the computer. No biggie ... the display gets real entertaining, but the computer doesn't "lock out" like some other models.

It's all just data ... gives me something to think about when I consider the efficacy of using ANY computer, including the desktop where so many tech divers run the deco program of their choice when creating their dive schedule.

Data isn't a bad thing. Whatever computer you choose ... or if you choose none at all ... is only as good as the brain you use to process the data it provides. There aren't any shortcuts ... develop a reasonable understanding of what (little) we know about decompression, and make your decisions accordingly. Work with your team. Plan your dive. Dive your plan. All your computer is gonna tell you is whether or not IT thinks you made good decisions.

Trust the computer in your head. If it isn't functioning properly, all the gear in the world ain't gonna help ya make a better dive ...

... Bob (Grateful Diver)

Thanks for the well crafted response Bob. Information is just more data that we can chose to act on or not. I have to confess that occcasionaly, when I am diving with my wife who uses her D-6 (set for 32% at least..) I take a look at her display to see what she is showing for bottom time remaining after a couple of repetetive dives. Nice to know that all those years of eating from Aluminium pots hasn't yet affected my memory or ability to add............(did I say the bit about the aluminium pots already?............)

 

[Blackwood]

Put 2 knots at the 20 foot mark, 3 knots at the 30 foot mark, etc. Then you don't have to count them as they fly past you.

I did that up to 50 feet on a shorter (~70') spool, but for the reason Bismark cited (14 knots at 140, etc.), and for the reason Orange_Diver mentioned (my team is my primary backup), I decided against it for anything longer.

 

[mempilot]

I realize I have not been that active in this forum the last few months, so maybe I missed a memo somewhere. But this is the DIR forum, where the expectation is that people will post DIR answers. Neither of your recommendations on this thread:

• If you are going to progress in your diving, you should consider having a computer and a bottom timer as backup.
• I'm actually about to start diving with two decompression computers, as tables and a timer are still archaic ...

are DIR. Therefore the posting that contains them does not belong in this forum.

My own experience has been that as I "progress in my diving", I rely less on a dive computer, not more. I actually own two of them, but could not even tell you where they are, as I have not used either one of them in about 6-8 years. In fact, I did a decompression dive about 2 weeks ago, where I used tables that I had cut in 2003, and still use for many of my dives. My buddies on the dive did the same deco as me, and we entered and exited the water together as a team. That is what DIR divers do.

DIR divers plan their dive and dive their plan, and the plan has to be known and agreed upon before the dive even starts, otherwise it is not a DIR dive. Therefore using a computer to "get out of the water faster" is not DIR. Using two computers is even less DIR. So the recommendations in your response have no place here. They may be appropriate for some other forum on SB, but not this one. I'm sorry if that makes you feel defensive, but that's how it is.


Restoring the elided text changes nothing about the meaning, and will not make it a DIR response.

Now that you've gotten that off your chest...

I'm sorry to know that you felt the need to say all that, even after I posted an apology for not realizing that the thread was in the DIR forum. I spend more time on the other technical boards where certain groups don't need to hide behind TOS.

The fact that your alias has the acronym in it, your avatar has the acronym in it, and you choose to reprimand me in the way you did says a lot about your agency and some of it's membership. Which, by the way, is the only one out of a dozen or so that advocate not utilizing a computer for technical diving. I can accept GUE's dedication to their philosophies, but members like you that feel they need to have a place to hide from the rest of the diving world so deserve it. I already apologized for answering a question in the DIR forum. I was even continuing to reading with currious interest how tieing knots in line and using markers to mark off intervals and guessing depth and ratio deco are safer than utilizing a computer (with proven models) and BT as backup. While the others have been most pleasant and their posts interesting to follow, divers like you are the reason many choose to stay out of the 'cult'.

Good luck with your quest to organize more DIR divers in the Atlanta area. If you come down to our neck of the woods, you would most defineately be invited to dive with us; and it would have nothing to do with your dive philosophy. It would be out of friendship and love of sport. I'm guessing that invitation would not be reciprical from your end.

Have a nice day DIR-Atlanta (that cracks me up). BTW, I'm not afraid to post my real name, and if I say something stupid, people can point the finger and say Eric said that!? You on the other hand, make people point the finger at DIR in general, and that is the problem.

 

[Elemental]

For anyone still reading this thread for content, the D3 has a timer feature with seconds for deco. I think Suunto recently discontinued the line, but you can probably find one here or there for less than half of a Tec 2G if money's an issue. It also has a logging feature.

Hm...useful AND decently priced. No wonder they discontinued it.

 

[SparticleBrane]

Why not just use a watch with a stopwatch feature?

 

[Elemental]

Depth.

 

[james croft]

I still get a lot of use from my Princeton Tech bottom timers. Bought a couple for about 15 bucks back in the day. They are nothing more than a waterproof stopwatch that activates by water pressure once I descend about 8 feet or so. No dead batteries. Wind 'em up and forget them.

 

[Blackwood]

Why not just use a watch with a stopwatch feature?

Most watches, while "water proof to XXX," aren't designed to allow the actuation of the buttons at depth.

But any watch that displays seconds can suffice if you see fit to remember when deco started

 

[DA Aquamaster]

I realize I have not been that active in this forum the last few months, so maybe I missed a memo somewhere. But this is the DIR forum, where the expectation is that people will post DIR answers. Neither of your recommendations on this thread:

• If you are going to progress in your diving, you should consider having a computer and a bottom timer as backup.
• I'm actually about to start diving with two decompression computers, as tables and a timer are still archaic ...

are DIR. Therefore the posting that contains them does not belong in this forum.

My own experience has been that as I "progress in my diving", I rely less on a dive computer, not more. I actually own two of them, but could not even tell you where they are, as I have not used either one of them in about 6-8 years. In fact, I did a decompression dive about 2 weeks ago, where I used tables that I had cut in 2003, and still use for many of my dives. My buddies on the dive did the same deco as me, and we entered and exited the water together as a team. That is what DIR divers do.

DIR divers plan their dive and dive their plan, and the plan has to be known and agreed upon before the dive even starts, otherwise it is not a DIR dive. Therefore using a computer to "get out of the water faster" is not DIR. Using two computers is even less DIR. So the recommendations in your response have no place here. They may be appropriate for some other forum on SB, but not this one. I'm sorry if that makes you feel defensive, but that's how it is.


Restoring the elided text changes nothing about the meaning, and will not make it a DIR response.

Could you flesh out your profile a bit. I'd love to know whether you are a GUE DIR diver or just a normal DIR diver.

Personally, I have come to feel the two are not the same in that GUE is a form of DIR you can only aquire in GUE courses from GUE instructors and then follow by adhering to GUE standards that are all in all pretty rigid. In contrast DIR was in the past taught from diver to diver in more of a mentoring relationship and outside a traditional cave environment the focus was on optimizing a basic hog configuration for specific non cave diving conditions. Consistent with that there was room for change and experimentation as long as everything had a clearly defined purpose and brought something to the dive. It was in short less rigid and more ammenable to user modification.

It makes sense that there would be differneces. You can't have a GUE organization and bring fairly inexperienced divers up to speed on technical diving in a comparative a hurry without having much more rigid standards and doctrine.

But several of the more conservative GUE sounding responses beg the question of whether this is truly a DIR forum or just a GUE forum.

DIR divers plan their dive and dive their plan, and the plan has to be known and agreed upon before the dive even starts, otherwise it is not a DIR dive.

As an aside I was reading an NSS journal over the weekend about exploration of Turner sink where the author (Casey McKinlay)was about 10,000 feet back in the cave and kept signalling for JJ to turn the dive as they had not only exceeded the plan but were pushing things a bit as well. So when both the project director and training director deviate from the plan and push the edge cutting normal safety margins and procedures, is this no longer a DIR dive? Apparently it is still a GUE dive.