Computers and backups - looking for pearls of wisdom from the more experienced

[sea_ledford]

Backup computer is pointless for rec diving. The point of rec diving is you’re never under a deco ceiling: anything goes wrong you can ascend anytime. Safety stop is nice but it’s not a real deco stop, you can blow it off and still be “safe-ish”; that describes all of diving anyway. It’s a good idea to have a backup computer on any big trip but it lives in your save-a-dive kit with your o-rings and wrenches, it doesn’t normally get wet.

Redundancy is great for the things that keep you alive, sure. With serious tec diving with serious deco the computer qualifies, sure. There are still plenty of things that will kill you at 20’-45’ (or 20”-45”) but computer failure just isn’t one of them.

Backups in no stop diving isn't to survive the current dive, it's to not miss the next 24 hours of diving.
If your only computer craps out on day 3 of a 5 day liveaboard, you end up missing an entire day of diving so you can go back to diving tables or a rental computer. If you aren't diving with both computers every dive, having a backup only saves you from the computer rental fee.

 

[tursiops]

Backup computer is pointless for rec diving.

I disagree, unless you are doing only once dive a day. Most of us, especially on travel, like to do 2-3-4-5 dives a day. I don't want to have to sit any of those out simply because I don't know my N2 status.

 

[nanohawk]

@tbone1004 is a technical diver/instructor. Deep dives, cave dives, significant deco, trimix, rebreather dives, are not uncommon for him.

Ninety five percent of my dives are no stop dives, within rec depth limits. My relatively uncommon deco dives average about 5 min of deco (1-14 min) at 10 feet. Only 1.6% of my dives have been deeper than 130 feet, half of those between 130-139 ft. Despite diving my Teric at 80/95, my dives are reasonably conservative. For my last 238 dives, my surfacing GF has averaged 55 (13-80).

So, that's how my dives are different than tbone1004's. I have a little over 2,100 dives in just under 25 years. How I dive today is based on that experience and what I have learned

Tbone is what I call an adventure diver. And as long as it's done safely all the more power to him.

2100 is an awesome number of safe dives. One day maybe I'll have applied enough wax to become a dive Jedi. (Karate Kid - wax on, wax off)

 

[nanohawk]

Backup computer is pointless for rec diving. The point of rec diving is you’re never under a deco ceiling: anything goes wrong you can ascend anytime. Safety stop is nice but it’s not a real deco stop, you can blow it off and still be “safe-ish”; that describes all of diving anyway. It’s a good idea to have a backup computer on any big trip but it lives in your save-a-dive kit with your o-rings and wrenches, it doesn’t normally get wet.

Redundancy is great for the things that keep you alive, sure. With serious tec diving with serious deco the computer qualifies, sure. There are still plenty of things that will kill you at 20’-45’ (or 20”-45”) but computer failure just isn’t one of them.

You won’t go far wrong with a AI Perdix as your primary computer though. You might not ever use its trimix or rebreather modes but the big bright screen, good controls, and bulletproof reliability will serve you every dive. That’s what I’ve got and I’m very happy with it.

It's pointless until it's not. I went back to my dive logs today to see what wet suits I was using. My wet suits are a little "less fresh" after several years of storage. I own a 3/2, a 3mm, a 5mm, and a 7mm. I wanted to see what I actually was using in cold water. For the record I hate cold water. But I have some refresher dives coming up locally and that means cold murky water.

Along the way I enjoyed reading my notes and looking at my weights and dive times. I came to the day my computer went on strike. The SmartCom issue I had was due to an incorrect O2 setting. Somehow during the surface interval the contacts used for controls had shorted out and this caused the O2 to be set incorrectly. That's my fault for not catching it, but I don't expect a setting to change when I haven't messed with it. So the computer went beserk thinking I was on a high O2. I still hate that computer. I want a computer that the settings don't change without my involvement.

Backups in no stop diving isn't to survive the current dive, it's to not miss the next 24 hours of diving.
If your only computer craps out on day 3 of a 5 day liveaboard, you end up missing an entire day of diving so you can go back to diving tables or a rental computer. If you aren't diving with both computers every dive, having a backup only saves you from the computer rental fee.

Exactly! Dive trips are expensive for me. I don't have the luxury of living where I can dive in nice clear water all the time. So when I do go diving I don't want to miss any trips because of a computer malfunction.

I'm still confused as to the real issue @nanohawk had with the Eon Core

For the record the Eon Core uses Fused RGBM (Not normal RGMB) this is an important distinctinction

I think GF with Buhrmann ZHF16 has a better margin of safety. That's just my personal opinion, based on the limited research I've done. So that automagically rules Suunto out. They have an unpublished RGBM model. Whether it appears to yield the same NDL limits or not is really secondary IMHO.

In addition, there were some things I did not like in the interface and they have a reputation for crap customer service. I have not dove the computer yet or modified the strap so I had the option of returning it. Voting with one's wallet is a strong way to send a message.

Shearwater has an open model and a reputation for stellar customer service. They also build their equipment to be less service dependent and I like being able to change my own battery if I needed to.

Everyone should have the gear that is right for them. There are many people who will enjoy and benefit from a sealed computer with the battery charged through contacts or magnetic energy (Qi). I prefer the serviceability path. If my rechargeable battery dies the odds of finding a AA battery are pretty good no matter where I am in the World. If that sealed Li-ion battery craps out, your computer is toast until it gets some fresh fairy dust at the factory.

 

[scubadada]

...Shearwater has an open model and a reputation for stellar customer service. They also build their equipment to be less service dependent...

Yes. Well, not always Teric owners, have you required repair or replacement service?

 

[tbone1004]

Tbone is what I call an adventure diver. And as long as it's done safely all the more power to him.

2100 is an awesome number of safe dives. One day maybe I'll have applied enough wax to become a dive Jedi. (Karate Kid - wax on, wax off)

What do you mean by adventure diver?

 

[nanohawk]

What do you mean by adventure diver?

Broadly speaking, some divers are motivated by adventure. They want to go into caves, deep places, shipwrecks, etc.

I'm one of the boring photographers. I'm happy to settle down on a patch of sand or hover over a large barrel sponge for 20 minutes looking at the critters and taking photos of them.

It is not in any way intended to be derogatory. I feel like the tech divers and adventure divers have pushed the boundaries and that makes us all safer and smarter divers.

 

[scubadada]

Ha, I guess it is not the PADI diver with 3 dives beyond OW I think that @nanohawk may be in a bit over his head in a few threads. Perhaps a good way to learn.

 

[MichaelMc]

Broadly speaking, some divers are motivated by adventure. They want to go into caves, deep places, shipwrecks, etc.

I'm one of the boring photographers. I'm happy to settle down on a patch of sand or hover over a large barrel sponge for 20 minutes looking at the critters and taking photos of them.

It is not in any way intended to be derogatory. I feel like the tech divers and adventure divers have pushed the boundaries and that makes us all safer and smarter divers.

Some are motivated by striving to be really good at an activity. Someone linked to an article on that a while ago that tech diving can fall in that category for many people. An interesting read in general. Not to speak for tbone.

 

[Blackcrusader]

Broadly speaking, some divers are motivated by adventure. They want to go into caves, deep places, shipwrecks, etc. I'm one of the boring photographers. I'm happy to settle down on a patch of sand or hover over a large barrel sponge for 20 minutes looking at the critters and taking photos of them.
It is not in any way intended to be derogatory. I feel like the tech divers and adventure divers have pushed the boundaries and that makes us all safer and smarter divers.

I think you would like the Liberty Wreck dive in Tulamben Bali. It starts at 5m depth and goes down to 30m depth and you can just spend time as a photographer in one spot for ages getting good shots of things there. By the way I consider myself a recreational diver. My average depth for my dives is around 15m depth so that means I also spend a lot of time much deeper. As you know I also like to dawdle and take photos. In Bali there are dive sites like the Liberty Wreck where you do not need a guide and I dive with a friend there. Sometimes we will plan a deco dive on nitrox and the night dives are really good as well. I did courses where Deco diving was normal recreational diving it is not technical diving. I've been diving since 1986 so have a few dives in lol. Now that the Philippines and Bali is open I plan on 5 dive vacations this year and getting in over 200 dives. 40 plus per vacation is normal for me.

I would happily dive with you on shallow dives just staying in one spot waiting for things to photograph or video. At the shallow depths you are diving I could get a 2 hour dive on an AL 80.

Also with the Perdix you and set it to Tec mode as I do and gas plan your dives. It's fun to learn how many liters of gas a tank holds and how much you use so you could plan a dive. You might think that is in the technical area if you are not doing that now.

For me my Cressi digital console is the closest things to a backup the only thing is doesn't give is NDL time. So even if my Shearwater failed on a dive I would ascend to 15m or less and continue the dive from there and just do a max 1 hour. I don't need a DC to tell me about NDL for that shallow depth as you won't exceed NDL in an hour.