Suunto HelO2 - Full Review

[scribley]

I think I'm missing somthing here, I've done enough dives to be able to roughly calculate my deco commitment for any given dive up to about 70m and 40 minute bottom times, but knowing the algorythum of my computer or not makes no diferance to this it's al about experiance of deco diving.


If the Helo2 gave me a ridiculsly short deco time I'm revert to tables just the same as I'd do with a VR3 or a shearwater or a deco fairy in a box. What those tables are cut with is up to you, personally I use V planner but you can sit down and write an implimentation in excel of your favorate flavor of deco "theroy".

Fin

Yes, but if you'd just spent over £600 on a computer and all it gave you was short deco times (or excessively long ones) you'd be a bit miffed wouldn't you?

I'm not suggesting that the Helo2 is like this and reviews like Marks help to give you confidence in the product. Opening up the deco algorithm to the world would inspire more. Thats all.

[Houseplant]

i know this is a little off topic, but is there any way of predicting what a vytec will do in terms of deco when it comes to gas switching?

[scubacaroline]

Thanks Mark for putting my mind at ease - had been following your early reviews elsewhere on YD when you first went off to Malta but then all went quiet. My money was slowly burning a hole in my pocket and couldn't wait for the conclusive review so went out and bought one and hoped you weren't going to slag it off on your return. So far am impressed for all the reasons you suggest

[DarrenA]

Thanks Mark

Excellent write up. Helped my buying decision a lot.

[tvenables]

I find that switching to a 70-80% mix takes about a third off the time to surface.

Tim

i know this is a little off topic, but is there any way of predicting what a vytec will do in terms of deco when it comes to gas switching?

[steve6690]

i know this is a little off topic, but is there any way of predicting what a vytec will do in terms of deco when it comes to gas switching?

I just bought a Vytec and you can set up which gases you plan to use and then do a simulated "couch" dive. It will auto-switch to the deco gases and you can see the ascent time reduce accordingly....

[alyabk]

Hi Mark - great review, thanks for posting that

Currently have an X1 and was thinking of buying the Helo2 as a backup. Had liked the idea of having a Suunto computer to use while leading groups of recreational divers that would show similar NDL to those of my divers. If I could use the same computer as a backup for tech diving as well, that's two birds with one stone. Hence had a couple questions:

-you mentioned that on -2 conservatism it gives substantially more aggressive limits than the Vytec. Did you by chance test at all if it gave similar NDL times on 0 conservatism setting?

-reading your review it seems like the level of conservatism on the Helo2 increases with the depth, and even on the most aggressive setting it gives +10% deco time vs the X1. I can probably live with 10% longer deco time on 70m dives, but wondering if the level of conservatism is going to continue to increase as you get deeper? if it shows 25% extra deco time after a 100m dive, that starts to be a quite a lot. Did you look at this at all? I thought you mentioned that some of your dives were deeper than 70m, was wondering if that made a difference

-finally, any indication of what happens to the unit if you ignore the more conservative deco stops and bend it? I assume you could still use it in guage mode at least

Cheers, Alan

[Silent Diver]

Dont know if this is any help but you may be able to get some answers about ignoring the deep stops from the manual:
Suunto - Downloadable Manuals - Suunto HelO2 - Diving Instruments

Edit just read the wifes manual and it says:
If deep stop is broken it does not cause the dive computer to go in to error mode. However there is penalty applied to the following decompressions.

[Mark Powell]

-you mentioned that on -2 conservatism it gives substantially more aggressive limits than the Vytec. Did you by chance test at all if it gave similar NDL times on 0 conservatism setting?

Yes they were simillar on 0 conservatism

-reading your review it seems like the level of conservatism on the Helo2 increases with the depth, and even on the most aggressive setting it gives +10% deco time vs the X1. I can probably live with 10% longer deco time on 70m dives, but wondering if the level of conservatism is going to continue to increase as you get deeper? if it shows 25% extra deco time after a 100m dive, that starts to be a quite a lot. Did you look at this at all? I thought you mentioned that some of your dives were deeper than 70m, was wondering if that made a difference

So far the deepest I have taken it is 80m so not sure how it behaves after that.

-finally, any indication of what happens to the unit if you ignore the more conservative deco stops and bend it? I assume you could still use it in guage mode at least

When you reach the deepstops it starts a timer for 1 or 2 minutes depending on the length of the stop. You can continue ascending past these and it wont penalise lock out. This is quite nice as you can come up from a 22m deep stop to 21m and do a gas switch or slow down the ascent rate to stretch the deep stop out between two depths. So you can break deep stops with no problems but I haven't broken the actual shallow deco stops.

[alyabk]

Thanks again Mark,

I actually ended up downloading the Suunto dive planning software... took me a little while to find on their webpage. When I ran a couple deeper dive plans on -2 conservatism and compared vs V-Planner, it actually gave some fairly aggressive times on 100m dives. I actually came up wi one or two that had less deco time than V-Planner. So I guess on -2 conservatism it should be ok

However, I did also take a quick look myself through the manual, and there was one area that struck me as strange. By my reading on pg 32-33 where it describes gas switching during a dive, it looks to me like it automatically prompts you to switch gases when PO2 dictates you can switch... so all well and good. But I don't see anywhere that allows you to manually enter gas switching mode if you miss the 15 sec window where the computer is prompting you to change. I find it very hard to believe that you can only change deco gases when prompted, but since i'm not seeing otherwise in the manual, i thought it worth asking. Did this come up during your testing?

Would also point out that on page 31 of the manual it looks to me like if you violate any deco stop by more than 3 min the computer goes into error mode and can then only be used in guage mode for 48hrs. I think that will be a bit less of an issue for me since I'm only looking to use the Hel02 as a backup computer, but that might be more of an issue for others. I certainly wouldn't want my primary computer to completely conk out if some emergency caused me to violate a deco stop

Cheers, Alan