Suunto HelO2 Trimix Dive Computer review
Last year I dipped my toe into trimix diving. I soon found out that it’s a lot more complicated than air and nitrox diving.
It wasn’t long before I was getting frustrated by using tables again; it seemed like a huge step backwards. It’s not the easiest task in the world sticking to a run time. I soon wished I could get a computer to use for this type of diving but the VR3 and other trimix computers appeared to be well out of my budget.
Then I saw the press release re the Suunto Helo2 the first dedicated Trimix diving computer from a mainstream manufacturer. I was very interested in it and I managed to get my hands on one. Over the last few months ive been putting it through its paces for Scottish Diver.
Initially a pre production unit was sent to me, instruction manuals were not available and the dive planning software was a beta version not the finished product.
This in itself was not a problem I had used a Suunto D9 computer in the past and found the menu’s very easy to navigate as will any diver who has used a Suunto computer before. In fact I would say it was extremely user friendly and I was soon imputing trimix mixes into the unit. This is the first plus point for this computer it’s extremely easy to use.
The HelO2 can dive to 120 metres and program and utilize up to 8 gas mixes. These can be set as “Primary” where the computer will include the gas in the dive plan and calculate time to surface etc. The “Secondary” setting is for gas that you do not carry but may use such as drop tanks or a buddies cylinder. These gas mixes’s will be stored in the computer but not used in the calculation until manually selected. Thirdly there is the “off” setting which is self explanatory. Mix’s that are turned off cannot be turned on underwater.
My first dives with the unit were purely observational whilst I dived using V planner tables (Conservatism = + 2). It’s extremely hard to compare a computer to tables. The Suunto HelO2 has 5 conservatism settings. -2 to +2 with -2 being aggressive and +2 adding in safety. I used the setting with 0 conservatism right in the middle, which is the default factory setting for the average diver.
The Suunto HelO2 uses a Suunto technical RGBM (reduced gradient bubble model) decompression model designed by Suunto and Dr. Bruce Wienke. Now unlike these guy’s I am no decompression theory expert so im not delving into explaining that but what I will explain is how the Suunto HelO2 dives.
On my initial dive following the V Planner tables run times looked similar for a 64 metre dive with a bottom time of 15 minutes. Everything worked well on the dive and the display on the HelO2 was clear and easy to read apart from the small dive time display on the bottom right of the screen which I found is partly obscured by the screen protector I could read the figures but not see the label. I repositioned the unit on my arm and this problem was solved. After 15 minutes I ascend sticking to my runtime. The HelO2 utilizes deep stops which are recommended but not compulsory. If you do not carry them out however you will receive a deco penalty at shallower depths. Sticking to my table runtime I missed the deep stops and when I had finished my deco requirements with the V Planner table the HelO2 was displaying a further 10 minutes of deco. From subsequent dives I can confirm that this was due to missing the deep stops.
The deep stop system was new to me and I really liked it. The computer gives a ceiling that can be ascended to; it’s highlighted “deep stop” to avoid any confusion with mandatory deco stops. Once the desired depth is reached a time display starts to count down in seconds. It’s neat and clear and once the time is up the next ceiling is displayed and depending on depth this is repeated until the mandatory deco stops are shown. Minimum ascent time is displayed and an hour glass formed by 2 arrows shows that you are in the optimum deco zone.
Once in the deco zone and using higher % O2 mix’s, the dive time display can be toggled through to view Oxygen information and the current PPO2 and your accumulated OLF% can be interrogated all by the push of a single button. Once again nice and easy.
Changing the gases on a dive is also straightforward. If the gas mixes are “Primary” The HelO2 will prompt you to switch gas once the safe PPO2 levels are obtained when a richer gas for decompression can be utilized. The display at the bottom left of the HelO2 screen can be toggled between max depth and the gas mix that you are currently using. Using mixed gases I kept my unit in the gas display showing O2% and He% for instance my bottom gas was 18/30. This display will start to flash and 3 beeps will occur (I didn’t hear them but I wear a really thick hood) when a better primary deco gas is available. A push and hold on 1 button and then a push on the select button to switch and select the gas. The HelO2 shows a confirmation message. Very simple and straightforward this is the beauty of this computer. I found it simplifies complex diving operations enriching the diving experience. The hand unit is only half of the package though!
The Suunto Dive Manager Version 3 is the software that can be used as a logbook of your dive. The USB interface from PC to HelO2 is included along with the software in the package which is a nice touch as other computer manufacturers charge extra for these items.
The Suunto Dive Manager Version 3 also interfaces with The Suunto Dive Planer which lets u plan dives setting Depth, Time, Gas mix’s to be used conservatism settings etc. From this you can print off a chart showing your runtime which is a great safety factor. This can be printed out to take as a back up on your dive. Another function is after your dive with partially empty cylinders this software calculates how much Helium and oxygen you require to blend your desired mix for the next dive. This is a great help if you are a trained blender on a live aboard trip or if you want to advise the fill station exactly what you would like in your cylinders.
Gas mix’s can be input directly into the HelO2 if you do not have a pc. If you do use the dive planner software though, you will be able to export your gas mixes and conservatism setting from the pc to the HelO2 whilst looking at your selected dive plan on the pc screen. I found this very pleasant to use, all the information you need is on a colour graph on your pc screen. All the deco and O2 requirements are visually brought to you with different colours showing different gas mixes and red’s showing where safe CNS O2 limits have been breeched or your equivalent narcotic depth of a gas has been breeched.
Once again its all very user friendly and easy to use and it certainly helped me plan deep technical dives. I found the package made it a much more interesting, enjoyable and easy task than purely looking at run times on tables.
So for technical diving in the 50-70 metre range as far as I could compare, for the reasons given above the HelO2 gave similar run times to V Planner tables. Also dive times were similar to VR3 computers which were used by buddies. If anything the HelO2 may give slightly longer deco penalties at the shallow stops. I like to keep things safe so this was perfectly acceptable for me. If you are young and fit and diving regularly you can always move the conservatism settings to the more aggressive -1 or -2 setting.
So for somebody like me getting into open circuit trimix diving this computer will make the whole process much more simple and enjoyable. It certainly gave me more time to focus on the diving and the freedom of using a computer rather than sticking rigidly to tables. In short I liked this product very much.
For people who use CCR rebreathers though the HelO2 is only for open circuit trimix. The Max Depth of 120 Metres may be restrictive for some technical divers.
I also used the HelO2 on some standard air/nitrox dives. As previously reviewed I compared the HelO2 to the Apex Quantum. My findings where that on the first dive of the day, although both computers went about their deco in different ways. When completing the deep stops for the HelO2 the deco requirements were almost identical, certainly within a minute.
On the second dive of the day I observed that the Apex Quantum required extra decompression penalties of up to 3 minutes. This may have been a penalty for lingering at depth completing my deep stops for the HelO2.
Conclusion
The Beauty of the HelO2 is its ease of use both the dive computer itself and the dive manager and planning software. The cost of the unit is currently £645 and as a package with a transmitter £955. This in its own makes it very attractive to divers being cheaper to buy than the VR3 and the Shearwater Pursuit. Also the software, pc interface come with the computer. So for divers undertaking open circuit trimix diving I expect the HelO2 to become a very popular unit. The Suunto name and the HelO2 could bring technical trimix diving to the masses.
The HelO2 is designed specifically for open circuit, so CCR divers will find limited use for this product. Also the 120M depth limit may restrict more adventurous divers. To most divers though this is an extremely useful and exciting product my only negative comment would be I found it hard to read the small displays at the bottom of the screen. Not the numbers themselves but the label identifying the max depth or dive time. The text is quite small and is partly obscured by the screen protector. PPO2 and OLF% and temperature are not obscured by the protector. Moving the unit on my wrist certainly helped and I was able to happily read the labels once again I stress that it was only the label dive time and max depth that I had difficulty seeing and not the units themselves. It’s a minor point. Otherwise the display is very clear and displays so much information to keep you completely in control of your trimix diving. Overall an extremely nice product to use.
Mike Clark
Last year I dipped my toe into trimix diving. I soon found out that it’s a lot more complicated than air and nitrox diving.
It wasn’t long before I was getting frustrated by using tables again; it seemed like a huge step backwards. It’s not the easiest task in the world sticking to a run time. I soon wished I could get a computer to use for this type of diving but the VR3 and other trimix computers appeared to be well out of my budget.
Then I saw the press release re the Suunto Helo2 the first dedicated Trimix diving computer from a mainstream manufacturer. I was very interested in it and I managed to get my hands on one. Over the last few months ive been putting it through its paces for Scottish Diver.
Initially a pre production unit was sent to me, instruction manuals were not available and the dive planning software was a beta version not the finished product.
This in itself was not a problem I had used a Suunto D9 computer in the past and found the menu’s very easy to navigate as will any diver who has used a Suunto computer before. In fact I would say it was extremely user friendly and I was soon imputing trimix mixes into the unit. This is the first plus point for this computer it’s extremely easy to use.
The HelO2 can dive to 120 metres and program and utilize up to 8 gas mixes. These can be set as “Primary” where the computer will include the gas in the dive plan and calculate time to surface etc. The “Secondary” setting is for gas that you do not carry but may use such as drop tanks or a buddies cylinder. These gas mixes’s will be stored in the computer but not used in the calculation until manually selected. Thirdly there is the “off” setting which is self explanatory. Mix’s that are turned off cannot be turned on underwater.
My first dives with the unit were purely observational whilst I dived using V planner tables (Conservatism = + 2). It’s extremely hard to compare a computer to tables. The Suunto HelO2 has 5 conservatism settings. -2 to +2 with -2 being aggressive and +2 adding in safety. I used the setting with 0 conservatism right in the middle, which is the default factory setting for the average diver.
The Suunto HelO2 uses a Suunto technical RGBM (reduced gradient bubble model) decompression model designed by Suunto and Dr. Bruce Wienke. Now unlike these guy’s I am no decompression theory expert so im not delving into explaining that but what I will explain is how the Suunto HelO2 dives.
On my initial dive following the V Planner tables run times looked similar for a 64 metre dive with a bottom time of 15 minutes. Everything worked well on the dive and the display on the HelO2 was clear and easy to read apart from the small dive time display on the bottom right of the screen which I found is partly obscured by the screen protector I could read the figures but not see the label. I repositioned the unit on my arm and this problem was solved. After 15 minutes I ascend sticking to my runtime. The HelO2 utilizes deep stops which are recommended but not compulsory. If you do not carry them out however you will receive a deco penalty at shallower depths. Sticking to my table runtime I missed the deep stops and when I had finished my deco requirements with the V Planner table the HelO2 was displaying a further 10 minutes of deco. From subsequent dives I can confirm that this was due to missing the deep stops.
The deep stop system was new to me and I really liked it. The computer gives a ceiling that can be ascended to; it’s highlighted “deep stop” to avoid any confusion with mandatory deco stops. Once the desired depth is reached a time display starts to count down in seconds. It’s neat and clear and once the time is up the next ceiling is displayed and depending on depth this is repeated until the mandatory deco stops are shown. Minimum ascent time is displayed and an hour glass formed by 2 arrows shows that you are in the optimum deco zone.
Once in the deco zone and using higher % O2 mix’s, the dive time display can be toggled through to view Oxygen information and the current PPO2 and your accumulated OLF% can be interrogated all by the push of a single button. Once again nice and easy.
Changing the gases on a dive is also straightforward. If the gas mixes are “Primary” The HelO2 will prompt you to switch gas once the safe PPO2 levels are obtained when a richer gas for decompression can be utilized. The display at the bottom left of the HelO2 screen can be toggled between max depth and the gas mix that you are currently using. Using mixed gases I kept my unit in the gas display showing O2% and He% for instance my bottom gas was 18/30. This display will start to flash and 3 beeps will occur (I didn’t hear them but I wear a really thick hood) when a better primary deco gas is available. A push and hold on 1 button and then a push on the select button to switch and select the gas. The HelO2 shows a confirmation message. Very simple and straightforward this is the beauty of this computer. I found it simplifies complex diving operations enriching the diving experience. The hand unit is only half of the package though!
The Suunto Dive Manager Version 3 is the software that can be used as a logbook of your dive. The USB interface from PC to HelO2 is included along with the software in the package which is a nice touch as other computer manufacturers charge extra for these items.
The Suunto Dive Manager Version 3 also interfaces with The Suunto Dive Planer which lets u plan dives setting Depth, Time, Gas mix’s to be used conservatism settings etc. From this you can print off a chart showing your runtime which is a great safety factor. This can be printed out to take as a back up on your dive. Another function is after your dive with partially empty cylinders this software calculates how much Helium and oxygen you require to blend your desired mix for the next dive. This is a great help if you are a trained blender on a live aboard trip or if you want to advise the fill station exactly what you would like in your cylinders.
Gas mix’s can be input directly into the HelO2 if you do not have a pc. If you do use the dive planner software though, you will be able to export your gas mixes and conservatism setting from the pc to the HelO2 whilst looking at your selected dive plan on the pc screen. I found this very pleasant to use, all the information you need is on a colour graph on your pc screen. All the deco and O2 requirements are visually brought to you with different colours showing different gas mixes and red’s showing where safe CNS O2 limits have been breeched or your equivalent narcotic depth of a gas has been breeched.
Once again its all very user friendly and easy to use and it certainly helped me plan deep technical dives. I found the package made it a much more interesting, enjoyable and easy task than purely looking at run times on tables.
So for technical diving in the 50-70 metre range as far as I could compare, for the reasons given above the HelO2 gave similar run times to V Planner tables. Also dive times were similar to VR3 computers which were used by buddies. If anything the HelO2 may give slightly longer deco penalties at the shallow stops. I like to keep things safe so this was perfectly acceptable for me. If you are young and fit and diving regularly you can always move the conservatism settings to the more aggressive -1 or -2 setting.
So for somebody like me getting into open circuit trimix diving this computer will make the whole process much more simple and enjoyable. It certainly gave me more time to focus on the diving and the freedom of using a computer rather than sticking rigidly to tables. In short I liked this product very much.
For people who use CCR rebreathers though the HelO2 is only for open circuit trimix. The Max Depth of 120 Metres may be restrictive for some technical divers.
I also used the HelO2 on some standard air/nitrox dives. As previously reviewed I compared the HelO2 to the Apex Quantum. My findings where that on the first dive of the day, although both computers went about their deco in different ways. When completing the deep stops for the HelO2 the deco requirements were almost identical, certainly within a minute.
On the second dive of the day I observed that the Apex Quantum required extra decompression penalties of up to 3 minutes. This may have been a penalty for lingering at depth completing my deep stops for the HelO2.
Conclusion
The Beauty of the HelO2 is its ease of use both the dive computer itself and the dive manager and planning software. The cost of the unit is currently £645 and as a package with a transmitter £955. This in its own makes it very attractive to divers being cheaper to buy than the VR3 and the Shearwater Pursuit. Also the software, pc interface come with the computer. So for divers undertaking open circuit trimix diving I expect the HelO2 to become a very popular unit. The Suunto name and the HelO2 could bring technical trimix diving to the masses.
The HelO2 is designed specifically for open circuit, so CCR divers will find limited use for this product. Also the 120M depth limit may restrict more adventurous divers. To most divers though this is an extremely useful and exciting product my only negative comment would be I found it hard to read the small displays at the bottom of the screen. Not the numbers themselves but the label identifying the max depth or dive time. The text is quite small and is partly obscured by the screen protector. PPO2 and OLF% and temperature are not obscured by the protector. Moving the unit on my wrist certainly helped and I was able to happily read the labels once again I stress that it was only the label dive time and max depth that I had difficulty seeing and not the units themselves. It’s a minor point. Otherwise the display is very clear and displays so much information to keep you completely in control of your trimix diving. Overall an extremely nice product to use.
Mike Clark
