Suunto Computers - Final Conclusion.

[Snoweman]

They are perfectly fine entry level recreational dive computers...my wife and daughter use Zoop's and with a week of two dives per day, the computer is flawless....if there were issues, then they wouldn't sell near as many nor be accepted by many dive shops around the world.

I think the reason dive shops (and dive operators) like them is that they are cheap and super conservative. I'm pretty sure that some dive ops use them in order to keep dives shorter than other computers. Plus, if one get's lost, it's not the end of the world. I have had a zoop since I got certified. The only thing I like about it is that it kept me occupied looking for another until the Perdix AI came out.

 

[Diving Dubai]

As and Alternitive opinoin to @Blasto

The 3 issues with the Suunto are:

The RGBM algorithm is suboptimal. The public ZHL-16B gives better deco schedules.

Depends on your view point. For instance I can (and have) dived an Eon and a Perdix, both set on their lowest consivertism to 40. The Eon gives marginally greater NDL. If you pop them into brief Deco, there's no real difference

The Suunto algorithm is a black box and it's impossible to predict and sync deco schedules among your team.

Suunto has DM5. You can plan along side other team members if they're using ZHL-16. Sure you can't use the same app but you can plan. Been there done that

Suunto computers will lock you out completely if you violate their rules too much, instead of giving you "emergency" deco data.

Yes, correct. if you punch through your deco ceiling and don't return to it within 3 minutes it will lock you out. Agree it could be better, equally never happened to me

Point 2 is irrelevant to NDL (rec) diving. Points 1 and 3 are relevant if you go into unintended deco.

Plan the dive, dive the plan. There should never be unintended deco.

Generally, with shallow, non-overhead dives, even light deco, Suunto are still OK. Deeper than that or with planned deco, you really want a ZHL-16 computer like a Shearwater.

Kinda disagree, but it's a personal preference


The Eon looks like a tech computer, but isn't; it's the same Suunto in a new skin. A bit expensive for what it is, in my taste. But if you're sure you'll stay within the bounds of recreational or very light tec diving, it's fine. If everyone around you uses Suuntos, that commonality can actually be a benefit.


The Eon (Steel and Core) as well as the DX all used the Fused RGBM which is different from the Standard RGBM. If divign with a Suunto on the normal RGBM you have to increase yoru conservitism otherwise there is a big mismatch, when getting toward 30m

Pricing depends on territory. Currently in the UK (where I buy) the Eon Steel with a Transmitter is less than a Perdix without. The Core is cheaper still

(By very light tec diving, I mean things like doing 2x80 sidemount on mostly rec sites, with <50m rock bottom, 1-2 stops - the kind of dives that are very routine.)

I'll use my Eon to 50m with 2 deco gasses and its fine. I run alongside guys with OSTC and again the deco schedule isn't too far apart. That said I am buying a ZHL16C just not sure it'll be a perdix. Once you've used the Eon with it's market leading fully customisable screen - everything else seems a bit backward.

Most entry level (i.e.) the cheaper end of the market use RGBM. It certainly errs on the side of caution. For the majority of divers, who are occasonal vacation divers its just fine

If someone who dives 10 times a year wants to buy a perdix and set it to 100/100 they can, and maybe they'll be okay

I have seen someone take a chamber ride diving a Suunto conservitivly to 20m with a total dive time of 40mins, on their first dive of the trip. It shouldnt' of happened but it did. That was the end of their vacation. The person wasnt' a novice, just over 500 dives - but only on vacation


One should always remember that whatever computer you strap on, they don't actually know how much dissolved gas you have in your body and how close you are to the M line

 

[Oz Chris]

I just did 25 dives (a mix of air and Nitrox) across two weeks with a Perdix as my primary and a Suunto Zoop console as a backup.

The Perdix was running in OC Rec mode, and the default medium conservatism (50/85 iirc) (I started with it on Low, but seeing as I’m 50 and could be fitter I dropped it back for this trip).

Pretty consistently the NDL of the Suunto was 5+ minutes longer than the Perdix (I followed which ever I hit the limit on first) (on low conservatism the Perdix gives you 2-3 minutes longer).

Not sure which computers people are comparing Suunto to when they assert they give you big penalises you for repetitive dives, but it’s not a Perdix on 40/95 or 50/85.

 

[JohnnyC]

The biggest issue with the Suunto's is that RGBM (all flavors) are proprietary to the point where it's a best-guess as to why it's acting the way it does.

The community has pretty well figured out that something that triggers the ascent alarm will penalize you, shorter than 1hr SIT will penalize you, less than 24 hour SIT will penalize you, jigsaw profiles will penalize you, etc. The problem is that these are unpredictable as to how they will penalize you. If you're a safe diver that practices proper ascents, takes long surface intervals, and dives square or ascending multi-level profiles, you shouldn't run into any issues.

The problem is, these are not always possible. Say a tourist cavern dive in Mexico, you may have quite a large variation in depths (some quite rapidly) over the course of the dive, and if you're diving multiple cavern lines at one site, you may have a shorter SIT than desired. These three all of a sudden may lead to a dramatically shorter NDL than other computers if you've already been doing a couple days worth of diving. If you don't check your planner at the beginning of the second dive, assume you have a decent amount of NDL, and are lax in checking your computer as you descend, you might find yourself racking up significant amounts of decompression obligation, even 10 or 15 minutes into a dive. Do a quick up-and-down 10 minutes into the first dive and you've already been pinged for a rapid ascent and a jigsaw profile, and they stack, and it doesn't matter how the rest of the dive goes, you're already being penalized for the next dive(s).

All of these are generally predicated on a diver not paying attention to their computer, and it's easy to castigate a diver for that behavior, but the reality is that this type of stuff happens all the time, and they end up following the guide for the rest of the dive, their computer locks out, and then they're dealing with a failure state.

Suunto's aren't bad, but you need to be aware of their foibles, and sometimes they do funky things without you knowing about it. I had a Vyper that never threw a violation on screen, but when put into logging software, it had an ascent alarm (only 5.48m/min according to the software) and a short SIT alarm, neither of which the computer displayed. I thought it was strange that I had such a short NDL, but didn't realize what had happened until I saw the desktop log afterwards.

Not all of Suunto's algorithms will react the same way all of the time, which makes it hard to pin down exactly what is happening and why. Doesn't mean I think Suunto's are junk, I think a Zoop is a great computer for a new diver provided they understand why it can be conservative, and make sure they follow what their computer is trying to say. However, I would not dive one for myself, and since I moved on from my Vyper, I haven't had any other "surprises."

 

[Blasto]

Depends on your view point. For instance I can (and have) dived an Eon and a Perdix, both set on their lowest consivertism to 40. The Eon gives marginally greater NDL. If you pop them into brief Deco, there's no real difference

Yeah. That's why I consider it a non-issue for light deco (in the technical sense). It's only when your deco schedule becomes long enough that there is time to distribute that algo choice begins to matter. And even then, it takes a while since the basics in how it's distributed.

Plan the dive, dive the plan. There should never be unintended deco.

That's where I respectfully disagree. Emergencies happen. Some emergencies keep you underwater.

It's in these emergencies that a good non-deco dive can turn into a bad deco one. And then a computer that gives emergency deco guidance as you're stuck between low gas and deco ceiling is preferable. Training and a cool head will matter a hundred times more than the computer, though.


Otherwise, I agree, the Eon is a worthwhile rec (and light tec computer and someone not planning on going full tec will be fine with it. But they asked why the tec community mostly favors ZHL computers and it's good to know.

 

[woodcarver]

Been using a Suunto D4i since we started diving and haven't felt limited by it. Purely rec diving and don't usually spend much time below 100'. We usually do 3-4 dives a day in 2 week stretches. These days it's mostly in Bonaire, shore diving, so SIs can be whatever we want; seldom less than an hour, often an 1 1/2+. It's rare that our dives are less than 75 minutes and always end due to lack of gas remaining, not NDL. Even in Coz we were limited by gas rather than NDL.

 

[Pierre B]

The problem with the Suunto is not just the software. It is also the hardware. Buy 3 dive computers Suunto: D6i SN: 34000870, D4i SN: 35100558, and D4i SN: 35100939. And the first one that had problems with the ring of buttons was the D6i, just after 6 dives. Suunto fix it. Then he failed the D4i 35100558 and repaired it, because he needed it fast. I had 10 dives. Then I failed the D4i 35100939, it was at the end of the warranty, with 12 dives and broke one tab of the module. I did not repair it I bought another brand. In summary: do not buy Suunto.

 

[Hatul]

The problem with the Suunto is that with its conservatism and quirks it is difficult to coordinate with others using a more liberal computer. If you are diving by yourself or a buddy with a Suunto, or understand this limitation it is a good computer.
I had one that I used as a backup for an Oceanic and after the first day it locked me out and was only useful as a depth gauge.

Same thing happened to me. I was using a Vyper to backup my Galileo Sol. After a slightly short surface interval the Suunto went into deco while my Galileo was way in the clear. Eventually I lost my patience and surfaced and the Suunto locked out for 48 hours. I just gave it away.

 

[kelemvor]

The RGBM algorithm is suboptimal. The public ZHL-16B gives better deco schedules.

Depends on your view point. For instance I can (and have) dived an Eon and a Perdix, both set on their lowest consivertism to 40. The Eon gives marginally greater NDL. If you pop them into brief Deco, there's no real difference

My understanding is that Suunto RGBM falls apart during multiple days of repetitive dives (such as you'd have on a week long dive trip). You're dealing with the overly conservative algorighym plus the tendency of the computer to penalize you with a lockout make it a non-starter for me. I do think I can say with confidence that it is "overly" conservative, too. Based on the simple fact that computers with more liberal algorithms aren't resulting in more divers with "undeserved" hits.

It's going to affect you when you're on a big expensive dive trip.

Imagine you're on a boat with 10 divers for a week. You're all doing the same dives, but your computer has locked you out while everyone else is okay. They're going to do the next days' dives using their computers. Meanwhile you have to make the decision to miss a day of your expensive trip, or punt and find some other sub-optimal solution such as borrowing/renting another computer or reverting to tables. Based on reports you read online, many people opt to keep diving without their computer in this situation. I'm not sure I would, but I don't think it's an easy decision. Either way, it really sucks and so I would do what I could to avoid the problem entirely.

So my opinion is to avoid all that mess and go with a computer whose algorithm you can trust (because you can double check it) and which will continue to serve you in all situations rather than trying to punish you because it doesn't like the diving you're doing.

 

[Diving Dubai]

My understanding is that Suunto RGBM falls apart during multiple days of repetitive dives (such as you'd have on a week long dive trip). You're dealing with the overly conservative algorighym plus the tendency of the computer to penalize you with a lockout make it a non-starter for me. I do think I can say with confidence that it is "overly" conservative, too. Based on the simple fact that computers with more liberal algorithms aren't resulting in more divers with "undeserved" hits.

It's going to affect you when you're on a big expensive dive trip.

Imagine you're on a boat with 10 divers for a week. You're all doing the same dives, but your computer has locked you out while everyone else is okay. They're going to do the next days' dives using their computers. Meanwhile you have to make the decision to miss a day of your expensive trip, or punt and find some other sub-optimal solution such as borrowing/renting another computer or reverting to tables. Based on reports you read online, many people opt to keep diving without their computer in this situation. I'm not sure I would, but I don't think it's an easy decision. Either way, it really sucks and so I would do what I could to avoid the problem entirely.

So my opinion is to avoid all that mess and go with a computer whose algorithm you can trust (because you can double check it) and which will continue to serve you in all situations rather than trying to punish you because it doesn't like the diving you're doing.

Two things:

Firstly lockouts. Your computer is only going to lock you out if you get into deco and then miss your stop. Unless you're Tech diving, then this is not a likely hood, unless of course you're say ignoring your computer, not understanding what it's telling you and get yourself into a position where you haven't got the gas to complete the stop.

Secondly, repetitive dives. I can only speak here from my limited experience of 400 dives on the Eon in the last 3 years. My longest expensive dive trip was 21 days, although I limited myself to 24 hrs off after every 6 days of diving.

I never had an SI of shorter than 90 mins and went to generally 3 dives sometimes 4 per day.

Not once was I limited by NDL, The dives were generally (max depth in m) 30, 30, 20, 10. Never an issue

If however you are having less than 60 mins Si, then RGMB will penalise you.

I can teach RD courses, where I might be up and down on the unresponsive diver, as long as I drop down and hang at 5-6m for a few minutes, everything is good, I can then lead a couple more dives that day and be in the water for another few days. Again no problem

I guess if someone wants to make 2-3 dives with a 60 min SI to say 30m using air, then they will get a conservatism hit. Not something I'd do - because I'll always use Nitrox and wont' have 60min SI so cant' comment