Diving two different computers - got "Suunto'd" - and a whale shark

[fmerkel]

Clearing in pleasant circumstances is one thing, less so when it's boring. The 'straw' that made my wife switch was because the viz on all the dives that week was lousy to 50' and didn't clear well until 75'. We had a great dive finding wolf eels that was just getting going when the Suunto said we had to leave. We spent 12' in a plankton cloud (cold water) staring at the screen. Yuck.
In Bonaire and a lot of our local shore dives I could care less as I'll be spending time in the shallows anyway. Usually Gods Pocket has fine viz in the shallows, it just did not this trip so we ran up against the issues the Suunto throws down for that style of diving.

 

[Dan]

I would like to get the boards thoughts on this. My wife and I both dive Shearwater Perdix, 40/85 GF. We did some diving this weekend and wore our old Suunto Zoop’s as backups – just in case something happened to the Perdix as we’re in the habit of doing now.

First dive, USS Oriskany, MOD 126, planned max 110, actual max 107. Perdix had us at NDL 2 when we started up the line, the Zoop had us at NDL 4. I just happened to glance at the Zoop when we hit the line.

Nice, long SI and back in the water with almost the same exact MOD, plan and depths. Back at the line with the Perdix showing NDL 2, started up up and it switched to NDL 1 – still no issues just cutting it close (come on guys, a whale shark was involved and we were heading up). A few minutes later, Perdix NDL showing was showing something like 30 minutes or longer as we did our deep stop. All is right with the world, and did I mention the whale shark?

Got to 20 and started our safety stop. When the stop was over, happened to glance over at the Suunto at about 15 feet and WTH? Ceiling and stop. Wife’s was showing the same. Plenty of gas, so we cleared it and went up.

We did 14 dives in the Flower Gardens to almost the same depths although a little shallower and it never gave us an obligation. This weekend in Pensacola, 3 out of 6 dives where the Perdix had us in the clear with no issues, the Suunto had us with a stop. 2 of the dives were less than 85’ on 32%.

We know the DM’s and captains fairly well, and because we did clear the Suunto's, they just laughed it off and said we got "Suunto’d".

I’m not spending another $1,600 on backup computers right now. House remodel, etc. so not really in the budget. Other than having a stop, what are the communities thoughts on diving two computers that are a little out of whack, when the opportunity isn’t there to have them match? We’re doing Cozumel for the first time in October and I doubt those DM’s would be as forgiving if this happened there

By the way, did I mention the whale shark?

I had similar problem with SUUNTO D4 as my primary dive computer & Scubapro SmartTrak as my backup dive computer. When the 10-years old SmartTrak caput, I replaced it with SUUNTO Cobra. Problem solved.

Speaking of whaleshark. Lucky you to see one during a dive. I went to Holbox, Mexico to see them by snorkeling in murky water back in July 2011. Then I found a site where you can dive in clear-blue water to see several whalesharks almost 99% chance. I saw 3 of them in 2 dives. That place is in Cendrawasih Bay in Papua, Indonesia. I went there in June 2015. Next week I'm going to Isla Mujeres to snorkel with whalesharks in clearer water (than Holbox). I heard tons of them are already flocking there now.

Here is a video of diving with the whalesharks in Cendrawasih Bay. Place you don't want to miss whenever you get to go to Indonesia, besides going to Komodo & Raja Ampat.

 

[Lorenzoid]

I dive with a Petrel and a Suunto as a backup, and I haven't had any issues. On the first dive of the day, the Suunto often shows more no-deco time than the Petrel (set at "Medium" conservatism in Rec Nitrox Mode, which I believe is GF 40/85). On repetitive dives, the Suunto starts to lag behind the Petrel. Your dives do sound more aggressive than what I typically do, though. I rarely see the NDLs get down into single digits. (But you did say there was a whaleshark involved.)

I second the comment by @MaxE about the Suunto's sensitivity to ascent rate. According to the manual, a momentary ascent rate greater than 39 feet per minute or a sustained ascent rate greater than 33 feet per minute will cause it to give you a "mandatory safety stop" (yeah I know that's an oxymoron) and show you a ceiling to stop at. I suspect Suuntos issue a stop for this reason--ascent rate--more often than for running out of no-deco time.

 

[Lizard Leg]

On our next dives, I will try to pay more attention to movement. Perdix is on left wrist, Suunto on right. With my big camera rig, left hand is the one that never lets go of camera, so computer is always in my line of site.

 

[geoff w]

I dived with a Suunto Vyper (which is basically a Zoop with backlight and gauge mode) for years, and about a year and half ago got a Petrel 2. My Vyper is in a console with SPG and compass, so it goes with me on dives. My wife just has a Suunto. When we're diving on vacation, we always stay down for the most conservative computer to clear. Like you said, we're underwater and blowing bubbles, so what's not to like about being underwater

We've had several Suuntos crap out on us, where the depth sensor keeps diving long after we surface. I really don't trust Suuntos any more

 

[Nemrod]

I cannot understand the purpose of using two different computers with two different algorithms? Nothing good will eventually result from that. Just because you own something does not mean you should use it. If wrong, so be it, I think you should use two computers, if two is what you want, that are at least of the same algorithm if not the same exact model. N

 

[rjack321]

If you put the suunto into gauge mode you won't bend it (which is going to happen routinely). Then if the shearwater craps out (least likely of anything on the market imo) just do a 10-15min safety stop using the suunto as a timer/depth gauge. Gas permitting. That pretty much covers every contingency.

 

[victorzamora]

If you put the suunto into gauge mode you won't bend it (which is going to happen routinely). Then if the shearwater craps out (least likely of anything on the market imo) just do a 10-15min safety stop using the suunto as a timer/depth gauge. Gas permitting. That pretty much covers every contingency.

Doing the next dive, however, would require a long SI to clear out any residual nitrogen the Suunto isn't accounting for. Not aimed at you, but I've seen people ignore that....I've seen people alternate between two different computers to get longer bottom times.

 

[RandomGuy1]

Doing the next dive, however, would require a long SI to clear out any residual nitrogen the Suunto isn't accounting for. Not aimed at you, but I've seen people ignore that....I've seen people alternate between two different computers to get longer bottom times.

Doing the next dive would simply require knowing the dive you just did and consulting a dive table.

 

[victorzamora]

Doing the next dive would simply require knowing the dive you just did and consulting a dive table.

Hahaha.....I totally forgot about tables!! And I learned on tables! I was diving nearly a decade before I ever got a computer!!

Yes, taking your backup computer out of Gauge mode and running a table-planned dive based on previous RNT is certainly a great option for spinning the backup computer up to speed to take over from tables and not miss a dive. I guess the core of my point remains, though, that RNT is a crucial component you can't ignore.