? for Suunto Computer Users

[Damselfish]

The laws of physics do not magically change depending on the computer you buy.

 

[Arraial]

I have a Suunto mosquito and used it recently on a live aboard for 3 days, 9 dives full bottle, 10 to 25 m. I had no mandatory deco stops. If you exceed ascent speed ( as Weng pointed out) or dive under 20m it will certainly suggest a 3m stop. Guess I would do them anyway

 

[RPanick]

I dive with my Cobra set to P1, rather than the default of P0, which makes it even more conservative. I fit the profile for most likely to get bent, so it makes sense. As stated early in the thread, the key is long surface intervals. You can dive 4 or 5 dives a day at the depths you talk about without a problem. Just remember, deep dives first, and long intervals where possible. A little extra time at the safety stop doesn't hurt anything either. If you do that, you don't have to worry about your computer, and are less likely to get bent.

The way to really make the computer let you dive agressively is to get certified for Nitrox. Its a safer way to do multiple dives-multiple days. Of course you can't always get Nitrox.

Bob

 

[DeWDiver]

Not to beat a dead horse, but conservative still can get you bent if you push it. My wife and I each dive Vypers (no AI cobras).
Two years ago in Cayman Brac dove 6 days for a total of ~22dives. By the end of the week was pushing deco on the last two dives. Was usually the first in and close to the last out. The Vypers showed I was closer to deco than those that had more aggressive computers and showed less bottom time available during surface intervals waits. Knowing I was "close to deco" was a great reminder to watch what I was doing. Others commented, including one gentleman who was 67 and have been diving since before there were BC (took his first DCS hit at 65) that this might not be a bad thing. People tend to push their computers and if they had done it to their deco limits they would be more likely to take a hit.

Unless you are willing to take a bigger chance or are a person who sips air, I wouldn't worry.

 

[peterjmaerz]

I've been diving my Cobra for years, often in multi-dive-day vacations. Just got back from PNG doing 4 to 5 dives per day for 12 days straight, without incident. Avoided coming closer than 10 minutes away from deco.

I admit to having been annoyed with the Cobra's conservatism in the past. Used to be I would edge into deco country after 40 minutes just from doing a weekend two-tanker with a deep wreck dive, 45-minute surface interval and a 60-foot drift dive, while my buddy was sailing along showing 20 minutes of no-deco time.

As a previous responder suggests, Nitrox was the key. Now I've got plenty of room to dive as long as my air holds out, as long as I dive reasonably intelligent profiles.

I actually dive with two computers: the Cobra and an Aeris Atmos Pro as a backup. It's amazing how much more liberal the Aeris is! Makes me realize how much safer I am diving the Suunto. Even though I don't have any of the DCS risk factors, I don't feel like playing chicken with paralysis or death!

Best,

 

[peterjmaerz]

PS,

mtsidford...My dives in PNG were all 60+, averaging 75 minutes. So, if you do the nitrox cert, you'll have plenty of room to do those multiple dives.

Best,

P

 

[geraldp]

I am sorry, but I think you misintepreted what happened with your computer. I have both a Vyper and a Mosquito, and they use the same algorithm as the Cobra. The computer will ask you to do a safety stop. It will show a STOP sign, but no ceiling. If you miss your safety stop, it will not sound an alarm, but it will NOT go into Error mode either. If you were doing a MANDATORY deco stop (with a clearly indicated ceiling), and blew it, then it WILL sound an alarm AND it will lock out for 24 hrs. So I guess that you were outside NDL and the Cobra was indicating a mandatory deco stop. The alarm can be difficult to hear...

vjongene is correct that the Cobra doesn't go into error by simply missing the recommended safety stop. It will definately go into ERROR if it tells you it wants a MANDATORY safety stop and you don't follow it's floor/ceiling guidelines.

The Suunto will give you a MANDATORY safety stop for two reasons: 1) Going into a decompresion dive (as vjongene states), or 2) continuously ascending at an unsafe rate. If you ascend between 33fpm to 39fpm it will beep at you and scold you, but it won't go into error. If you exceed 39fpm continuously it will flash STOP and give you a FLOOR/CEILING for a mandatory safety stop. Actually the ref manual states "above 39 fpm or continuously above 33 fpm". If you violate the resulting required safety stop it will lock out.

On my first dive with my Cobra in Cozumel earlier this year I lost control of my bouyancy on ascent and quickly (i.e. >39fpm) shot through the (recommended) safety stop. As soon as I hit the surface I immediately upended and dropped down to 15 feet and stayed for 3+ minutes. The computer showed I was at 0 feet during the whole safety stop! All subsequent dives the Suunto worked fine. When I got back I contacted Suunto to ask what happened. It turns out that I violated the >39fpm ascent rate AND blew through the safety stop the Cobra started to go into an ERROR mode. Because I immediately dropped back down to 15 feet (within the 20 second sampling rate) it took itself out of ERROR mode, but it remained confused for the rest of that dive. When I uploaded my profile it showed exactly what happened.

btw I have NEVER heard my Cobra beep underwater... perhaps because I usually wear a hood.

 

[simbrooks]

Vyper here - found it to be fine so far, but i have mostly done 2 dives per day, so wasnt much to compare. On nitrox it gave me way more time than i had air to use, i am sure most other computers would too. I have done 8 dives in one weekend in the 30-55ft range, so kind of like a mini liveaboard, and didnt notice any problems with myself or the computer - however i also didnt push the NDL's. The nearest i have gotten to NDL's is about 5 mins at 60ft on my second dive of the day, but that was after only a 30 min SI. I try to keep my ascents in the first or second indicator, ie about 6-12ft/min, occasionally it creeps up to 20ft/min range, but very rarely (usually when i am reeling in the float/flag line) and it seems happy with how i dive to give me enough time for my air consumption (which is still dropping, now around 0.55cuft/min) - woohoo. We paid slightly less than US MSRP by buying the computers from Canada, i know you can get them about $20 cheaper at LP, but these had manufacturers warranties too.

 

[aquasport]

I dive a Suunto Vytec and yes, it is very conservative. Some of my dive partners use Cochrans and they are way more aggresive. Someday I compare my NDL to theirs while we are at depth. I will have 0 min left and they will have as much as 12-13 min remaining ot NDL.

Here is the deal, In the last month. Two of my partners diving Cochrans both got bent (different dives on different days). I dove the same profile as them and I am fine. They are not.

So some days I wish I can stay down just a little longer but then I think about the fact that I am not bent.

I definately notice a reduction of NDL as I dive repeatedly over a number of day. Suunto software takes the previouse 4 days of diving in to consideration. In order for me to get a good clean start to a dive day, I will need to "wash" my computer out by not diving for 2-3 days before.

Hope this helps.
Henry

Got a question im looking to buy a vyper just because its conservative, going to bonaire in aug will i have a problem diving 4 times a day for 6 days?

 

[Henry]

Got a question im looking to buy a vyper just because its conservative, going to bonaire in aug will i have a problem diving 4 times a day for 6 days?

logic would indicate that you will not have any problems with 4 dives a day if you dive proper profiles.

If you dive less than 100 feet for 45 min to 1 hour with a nice easy ascent on each dive. Then plan a surface interval of at least one hour (the latter dives should have even more SI). You will not have any problems at all.

The last dives obviously should be shallow, not only for safety reasons, the computer will also allow you more NDL.

Keep in mind that the latest research shows that long swims at shallow depth are more likely to load the slow tissues such as fat. You are in the water for much longer period of time therfore allowing time for the fatty tissues to load up with nitrogen. It also takes longer for you to off gas as well. In theory making you more likely to get a hit of DCS.

A good way to deal with this is to dive with nitrox with a conservative profile. An added personal opionion would be no alcohol, easy on the hot showers and keep the heart rate down.

Henry