Spare dive computer on camera?

Hey all, 

I've currently got a d4i as my main computer. Recent battery woes on a trip really made me think about having a spare computer, and how a spare computer could easily be planted on the camera rig. 

Questions please:

1. With the d4i I'm not hugely impressed with the battery life (I don't get to do more than maybe 40-50 dives a year and a £40-50 bill annually to service it is starting to add up!). And I feel it may be overly conservative. Is there a good alternative to the d4i or should I keep it as my primary?

2. If suunto is decent, what kind of secondary is good for an 'on the rig' computer? Id love one with a large display, perhaps a zoop or similar, assuming suunto use the same algorithm across the board.

3. What's the preferred setup of a backup computer on the camera rig? Are there best practices here? Pictures would be great! ☺ 

Thanks! 

SineTwo 

Ouch, a £40 a year bill seems very steep. First time I've heard of that issue on the d4i. Suuntos have certainly been very popular dive computers. 

It depends of course how much diving you do, but when I ran a dive operation I found having to return a computer to a dealer for a battery change an utter pain. This led me to switching to a computer I knew I could change the battery myself. I bought a Uwatec/Scubapro Galileo Luna which has been brilliant and which needs a user-changeable battery swap about every 350 dives.

I recently "upgraded"  (shiny new toy syndrome) to the Galileo G2 which has a rechargeable battery.

As for secondary computers, it's like all these things, how much do you want to spend!? The Luna/Sol/G2 are perfect for "on-rig" computers: big customisable screens, easy to read, air-integrated and easy to secure to, say, a ULCS-style arm fitted with Stix floats mounted horizontally along the top of the housing. (Sorry, can't send a pic at the moment - my housing is being serviced). I've been using this set up for the last few months and really like it - and now I actually check my dive computer rather than, errr, forgetting it on my wrist.

(I've now got a Luna for sale if you are interested!)

9 hours ago, sinetwo said:

2. If suunto is decent, what kind of secondary is good for an 'on the rig' computer? Id love one with a large display, perhaps a zoop or similar, assuming suunto use the same algorithm across the board.

I think there are a few factors here. 

1. Form factor - You are probably going to want a wrist computer due to size; however, that is also subject to your eyesight. I'm 53 and my eyesight is crap but I wear contacts so it isn't as big of an issue.

2. Algorithm - Some people dive with computers that use the same algorithm, some prefer computers with different algorithms and dive the most conservative NDL on any given dive. All of my computers use the "standard" Buhlmann with gradient factors.

3. Functionality - Are you a Trimix diver or do you expect to be? Do you plan to dive CCR and want an off-board internal setpoint feature? Etc.

Personally, I will never dive a Suunto again. I had a DX for one dive trip and retuned it after it went into violation mode twice for stupid reasons (I can explain more details if anybody really wants to know). Luckily, I was just testing it out and it wasn't my primary computer.

I currently use a Shearwater Teric and I wrap it around my left strobe arm. I need multiple gasses, Trimix, and CCR capabilities so it somewhat limits computer choices. I like that the screen is easy to use and it has some specific features that I find useful in a "oh crap" bailout situation if both of my rebreather onboard computers fail.

However, the Teric isn't cheap.

In the past, I've had good luck with Oceanic computers. I find them easy to read, intuitive and well priced for what you get. Nowadays, they also give the ability to use either the relatively liberal Oceanic DSAT algorithm or the more standard Buhlmann (I think the 16C variant but not sure).

If you don't need Trimix or CC, then I would go with one of the wrist-mounted Oceanic computers. In fact, they have one called the "B.U.D." which is some kind of backup computer and has a MSRP of $200. I'm not sure what the limitations are, but it could be an option. 

If you want/need, I can send a picture of my computer mounted on the strobe arm, but it is pretty straightforward. 

I have a D6i mounted on my wrist and a Suunto Vyper mounted on the strobe arm. Both are paired to the same transmitter.

I also have a SPG on a short hose bungee'd out of the way but accessible if the tank transmitter fails mid dive, which it has.

I do my own "service" of both computers... very simple to do and the cost is only that of a CR2450 battery. Two small screws and you are in. Treat the O ring gently and it can definitely be re-used, just a whiff of O ring grease needed.

The battery in the transmitter can also be changed, but requires a specific battery which Suunto sells with an O ring. These are available on eBay.

The computer batteries are available at any pharmacy, and I always travel with spares, and a spare transmitter kit. A couple of screws, O ring grease ... Bob's Your Uncle.

There are many detailed instructions on The Youtube.

Ian

The Cressi dive computers are dirt cheap and have a user replaceable battery which is so simple you can just use a medium sized coin. The battery is a pretty standard CR2430, less than $5. I just replace the battery before every trip. I don’t like the idea of rechargeable - to much bother and does not give a long uptime.

I have several with different strap colours so that I can distinguish between mine and my dive buddy (usually my son). You can download dive history with a cradle but I don’t bother. You can set how conservative you want to be with your dive table. Depending on the model you can have various gas mixtures.

https://www.cressi.com/catalogue/index.asp?CategoriaCOD=005008


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Wife and I each carry two Suunto Zoops each. One in a console and one on the wrist.

I change out the batteries every 100 dives.

As Okuma, Angus Parker and Ian Marsh related my advice also is keep it simple.

I've been using the Suunto ZOOP computer for years, owning 4 (one is the wife's) and have picked them up used for barely $100 USD. I wear one on each wrist loosely. They're light and I want my computers on me versus a camera I may ditch in an emergency to to help my buddy.

Diving NITROX 32 in sport diving depths even if doing 5 one hour dives daily in Philippines I've not run out of bottom time. After an hour or so I'm ready to come up for a coffee anyway  

I see lots of gear on trips I organize. Most sport divers (and UW hobby photographers) dive above 100' / 30M to enjoy themselves. If you're in this group a simpler user changeable battery Suunto should work fine. The Cressi models have worked well for some fellow divers, too.

As we age unless you're a Navy SEAL fitness level I don't see the logic risking injury for 5 more extra minutes of bottom time versus being cautious and conservative.. I want to dive into my 70s and 80s  being currently 67 and been diving for 50 years. 

Computers have been the single greatest advancement for fun, safe comfortable sport diving in my opinion. But it's still just a tool to be used intelligently.

Last thing would be transmitters. I've found them to be an expensive solution to a non-existent problem. I route a short braided SPG over my shoulder bungied to my BCD inflator hose. I confess I stole this from a firefighter friend looking at his SCBA pack and how his "contents gauge" was routed. I never liked hoses routed low and with my method I can see it without even picking it up.

I do have a bungie holding the BCD inflator / SPG end  close to my waist so it doesn't drag the bottom.

SPGs are cheap and I travel with a spare hose SPG. I put 2 or 3  dive computers in thin neoprene beer holders and toss them in my backpack carry on.

Just one old guy's opinion.

David Haas

Thanks all for your input. I think it's most likely I'll get a cheap zoop and slap that on the floats circumference as it gives me what I need and works as a backup. 

Still I'm fairly miffed about my d4i needing to change the battery yearly with a £40 service and pressure test.  I don't hit 100 dives a year and whilst in storage I put the contrast to the lowest to conserve battery.

Whilst I'm happy to do it myself I don't want to flood the computer. It may be worth me doing it myself and getting it serviced every few years? 

Changing the battery on the D4/D6 is not at all complicated. Just make sure that the o-ring is in the right place. I have changed mine and my wife's several times with no bad results and the battery is like $3. You can buy the kit with the correct o-ring for $10 or so.

Bill