Do any computers apart from Suunto show the floor?

[Hatul]

I make decompression dives.

My Suunto Gekko tells me whether I'm above the floor or not, "floor" being defined as:

"the deepest depth at which the decompression stop time will not increase. Decompression will start when you pass this depth during your ascent".

When I'm below the floor, it shows an up arrow and "ASC TIME" blinks. I really like this feature because, for example, it helps me decide whether to stop to video something at 15m during my ascent.

However I'm looking to switch away from Suunto because the Gekko's algorithm is too conservative for me. I much preferred the algorithm of my old Uwatec Aladin Pro, so I am thinking of getting a Subgear XP-10. But as I understand it, that computer (like the Aladin Pro) gives no indication of the floor.

Are there any other computers apart from Suunto that show if you're above or below the floor on a deco dive? As I'm in Thailand I'm particularly interested in the more mainstream brands that would have dealers here (Scubapro/Uwatec, Oceanic, Mares etc.).

I have the Vyper and the Galileo Sol. In the Vyper the floor is only indicated when in deco mode and only shows as an upward arrow when below the floor, to advise you to go up and get out of deco mode. It's marketed as a non deco computer.

The Galileo does not show the floor but does give "profile dependent intermediate stops" PDIS. These are some distance above the floor to allow a stop and still unload nitrogen. You could use these as an indirect indication-- if you stop at the PDIS you know you're above the floor and you're decompressing. I believe the Subgear is also UWatec and may have similiar PDIS indicator, but you should check in the online manual.

One thing to consider if you're doing deco dives to chose a computer designed for deco diving, and take tables as well in case the computer goes kaput or locks out.

 

[DiveNav]

I make decompression dives......

Theoretically speaking ... all diver are decompression dives.

.....My Suunto Gekko tells me whether I'm above the floor or not, .........
During my ascent on a decompression dive, my Suunto Gekko shows me if I am off-gassing or still on-gassing. .....

Again, theoretically speaking .... it depends on which algorithm is being used. Most algorithms use several "compartments" to simulate Nitrogen absorption / release. Most likely during an ascent some compartments are still on-gassing while others are already off-gassing. Among those off-gassing, the "leading compartment" is the one the drives the ascent profile.

During an ascent, things change continuously every second / inch.
To make life easier for the diver, almost all dive computers have discrete levels (every 10ft / 3m) and ranges.

As an example, if at time T0 the leading compartment says that the deco stop should be 8.9 ft, and after few seconds it says that the stop should be 8.7 ft, the computer will show it as a 10ft deco stop where the next deeper deco stop would be 20ft.

If you are deeper than 20 ft the dive computer will tell you to ascend (up arrow) to a depth equal or deeper than the current deco stop level (10ft).

If you are shallower than 20ft but deeper than 10ft you are in the deco stop "range" and the dive computer will tell you to hold your position.

If you accidentally ascend shallower than the current deco stop, the dive computer will yell at you and tell you to descend a bit (deeper than the current deco stop)

All modern dive computers do implement these concepts.

 

[DuboisP]

Directly from the Gekko manual


Page 4 second WARNING on the page.

http://www.simplyscuba.com/pdf/scubamanuals/divecomputers/Gekko Manual English.pdf

DIVES WITH REQUIRED DECOMPRESSION STOPS ARE NOT REC-
OMMENDED. YOU SHOULD ASCEND AND BEGIN DECOMPRESSION
IMMEDIATELY WHEN THE DIVE COMPUTER SHOWS YOU THAT A
DECOMPRESSION STOP IS REQUIRED! Note the blinking ASC TIME
symbol and the upward pointing arrow

all diving computers user guides have this warning

the Helo2 is a trimix computer and has this warning

 

[dmoore19]

So it says it is a recreational computer and is not designed for use in Decompression diving, but that means nothing. Got it.

all diving computers user guides have this warning

the Helo2 is a trimix computer and has this warning

 

[tursiops]

all diving computers user guides have this warning

No, they don't.

the Helo2 is a trimix computer and has this warning

This tells you more about Suunto than about dive computers in general.

I believe the Tissue Bar Graph on the Shearwater Petrel is exactly what you are looking for.

 

[Damselfish]

the Gekko is a true decompression computer, as other Suunto.
it doesn't have features as backlite or nitrox, that's all.

the Gekko does Nitrox

 

[DuboisP]

No, they don't.

which ones ?

 

[bubblevision]

Thank you everybody for your replies.

not directly, but i believe all deco computers provide this information indirectly via the decompression stop duration value. if it is getting larger then you are below the floor. i am not a deco diver, but that is my understanding of how your old aladin pro worked.

Clearly it's possible to wait and see if the decompression duration value is getting longer or shorter, but that might take a valuable minute of attention, unlike the instant feedback of the Suuntos.

- you are doing deco dives

Not always but in a repetitive dive situation I am comfortable with doing some extra minutes under a 3m ceiling. We're not talking lengthy deco stops at multiple depths.

- you do not appear to have a plan
- you are riding your computer

To some extent that's often true. As a professional videographer with thousands of dives I've had a lot of practice at it. It's usually my gas supply that limits the dive rather than deco requirements.

- you want a more aggressive computer

In my experience and tests in a repetitive dive situation such as a liveaboard, by the second day a Suunto RGBM100 computer gives typically 8 minutes of stops at 3m (plus the 3 minute safety stop) when an Aladin clears. This can become a real problem when everyone else on-board including your buddy has Uwatec/Scubapro/Subgear/Oceanic/Mares etc.. I'm comfortable with the well-proven Buhlmann ZH-L8 ADT algorithm that served me well in my Aladin Pro. I don't want anything more aggressive than that.

The Galileo does not show the floor but does give "profile dependent intermediate stops" PDIS. These are some distance above the floor to allow a stop and still unload nitrogen. You could use these as an indirect indication-- if you stop at the PDIS you know you're above the floor and you're decompressing...

Interesting idea as a workaround but if the psychedelic frogfish is at 15m, it's at 15m.

I believe the Tissue Bar Graph on the Shearwater Petrel is exactly what you are looking for.

Thank you. That does indeed look like an enhanced version of what I am looking for, although the computer seems rather complicated, expensive, and a little overkill for my purposes.

 

[KenGordon]

You could try a more 'tech' Suunto such as the helo2 which has a couple of less conservative settings. Install the DM4 or 5 SW and plan a typical series of dives to see how the deco pans out.

 

[Sevenrider860]

Directly from the Gekko manual


Page 4 second WARNING on the page.

http://www.simplyscuba.com/pdf/scubamanuals/divecomputers/Gekko Manual English.pdf

DIVES WITH REQUIRED DECOMPRESSION STOPS ARE NOT REC-
OMMENDED. YOU SHOULD ASCEND AND BEGIN DECOMPRESSION
IMMEDIATELY WHEN THE DIVE COMPUTER SHOWS YOU THAT A
DECOMPRESSION STOP IS REQUIRED! Note the blinking ASC TIME
symbol and the upward pointing arrow

That same warning is in the DX manual (Page 11). The DX is marketed as a technical dive computer for decompression diving.