Convince me to get a bottom timer...

[nilsdiver]

With time that will wear off in salt water. I used a permanent marker to note where to tie the knots, but those markings are all but gone. Besides, you can use the knots even if you lose vision.

AG does recommend knotting. He refers to an incident where he and his buddy had dramatically different depth readings, and he shot a bag to determine which one was right.

Personally, I've never tried using it as a ruler. When I shoot, I let it go up fast. I don't control the unspooling enough to count knots or even see them. But I have used them to ascend blind.

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.

 

[orange_diver]

By the way, I see that you guys are all west coast DIR trained. Does AG suggest the knots and single bottom timer thing?

Even tho we've taken RD from AG, the vast majority of our training is with an instructor who is GUE trained and the knots and single bottom timer thing are straight from his mouth to our ears.

AG knots his spools i know as Blackwood said, and the DVDs and pics i've seen of him only show him with one BT but then again, i don't go about collecting pics of AG! He very well may on his more aggressive dives i have no idea, but i wouldn't bet on it.

 

[Bismark]

no worries. s'all good.



i made a previous post you prolly missed that would clear up this for you. basically, i had to bring up RD because that's the only way to for the OP to use a BT and not get penalized for multi-level dives b/c you are using tables. then i suggested he run the computer as a computer b/c no one is going to teach RD over the internet but buy one with the ability to switch to gauge later on after Fundies.





[I]What do you do in the event you lose your teammate? You won't find a stronger proponent of team diving than me, but taking along an extra bottom timer is such a non event I believe the upside is far more "up" than the downside is down.
[/I]


I always know what depth i'm at so let's figure it dies at 150' and i get separated from my team, if i was below 150' (max would be 180, but i rarely hit that for more than a min or two, my avg depth is 150-160) i feel pretty confident that i could rise in the water column 20 - 30 feet, stop and shoot my bag. If when i shot my bag i realized i hit 100' and missed my 110' deep stop, i'll add the minute there and perhaps an extra at 70' when i switch. this isn't an exact science as you well know. i'll have been ascending plenty slowly anyway.

[I]You must have excellent viz there all the time I don't think I could tell a 20 or 30 ft change in depth between 150 and 100 with 5' of viz. I appreciate how you are going to adjust your deco times for mistakes in depth, but how do you know you are at 100' or 110'? Do you plan on counting the knots as they ascend? Even sending up a 3' smb from depth and trying to absolutely control that smb's ascent, while counting knots, while in crappy viz, while tracking your buddies, is going to be a bit of task loading I would think. [/I]



Suggestion noted, i'm sure you speak from more experience than i have. What if one starts acting strangely and gives you a different reading than the other. Which one do you trust then and how do you reconcile?

I find they are usually within a foot or so from each other. Within tolerance anyway. Which one is right if they are wildly out of step? Good question......what about those buddies again......??


That's why i went with the Tec2G. it's WAY more annoying to them when i'm calling deco waiting for the minute to flip over.

[I]ain't that the truth[/I]



Thank you. Diving is a journey to me, I don't care for the "trophies" (cards for cards sake, deep bragging rights, etc) too much.

[I]Best of luck. Good approach. I follow the same one........[/I]

 

[Bismark]

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.

14 knots at the 140', 15 knots at the 150'..............

 

[Bismark]

Even tho we've taken RD from AG, the vast majority of our training is with an instructor who is GUE trained and the knots and single bottom timer thing are straight from his mouth to our ears.

AG knots his spools i know as Blackwood said, and the DVDs and pics i've seen of him only show him with one BT but then again, i don't go about collecting pics of AG! He very well may on his more aggressive dives i have no idea, but i wouldn't bet on it.

A difference from GUE trained and GUE instructor I think. I am going to ask around about the two bottom timer thing.

I will also ask AG about his thoughts.

 

[orange_diver]

[I]You must have excellent viz there all the time I don't think I could tell a 20 or 30 ft change in depth between 150 and 100 with 5' of viz. I appreciate how you are going to adjust your deco times for mistakes in depth, but how do you know you are at 100' or 110'? Do you plan on counting the knots as they ascend? Even sending up a 3' smb from depth and trying to absolutely control that smb's ascent, while counting knots, while in crappy viz, while tracking your buddies, is going to be a bit of task loading I would think. [/i][/I]

no doubt it's not a scenario i'd like to get into, it wouldn't be pretty but i'm confident i would be able to do all the deco i would need to. but then again, to get there would need both BT and buddy loss failures to happen, and the way my team dives and looks out for each other at all times i'm not losing sleep over it.

[I]I find they are usually within a foot or so from each other. Within tolerance anyway. Which one is right if they are wildly out of step? Good question......what about those buddies again......??[/I]

EXACTLY! those darn buddies always there when ya need them.

[I]That's why i went with the Tec2G. it's WAY more annoying to them when i'm calling deco waiting for the minute to flip over.

ain't that the truth[/I]

Especially when your buddy is feeling queasy from the swells and wants to get the hell outta there.

 

[orange_diver]

A difference from GUE trained and GUE instructor I think. I am going to ask around about the two bottom timer thing.

I will also ask AG about his thoughts.

Cool. Looking forward to what you find out.

 

[DIR-Atlanta]

Why is this in the DIR forum?

Excuse me? Someone asked about computers vs bottom timers. Please tell me you are not going to start some kind of debate here outside of advising the pros/cons of both computers, BTs/tables?

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.

BTW, if you are going to quote me, please don't snip off the end of sentences where what is left behind will be taken out of context.

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

 

[DIR-Atlanta]

I posted this in DIR because I plan to take fundies next year, and if I like it to continue with GUE training, so I was asking the opinions of those who are farther along the same road I plan to take. If it's in the wrong place, by all means please move it.

There is nothing wrong with your question - I wish I could say the same for some of the responses. For Fundies, a BT or a computer set in gauge mode will be fine.

Thanks to everyone who's given their opinions and experiences, I expected a much stronger "Get the BT and no computer!" response.

At the purely recreational level, use of a computer is generally considered acceptable, as long as you are not using it as a substitute for basic dive planning. Often there is a tendency for people to use a dive computer as a sort of "idiot light", and blindly follow what it says. That is not recommended for DIR divers and should be avoided. In fact, as you progress in your DIR training, you will find that you rely less and less on a dive computer, and use RD or pre-cut tables for most everything.

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.

 

[MXGratefulDiver]

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)