Perdex/petrel w/ a suunto backup? Pointless?

[TT_Vert]

I assume it is given that the suunto and it's conservative algorithm will probably lock out on some of the dives I do that the perdix/petrel won't even blink at. Anyone use a suunto as a backup? I really like the computer aside from it being like a nagging wife wanting to go shopping and would not mind having it as my backup clipped to a D ring but I really think that I may lock it out. Opinions?

Dave

 

[northernone]

I agree you'd get locked out frequently unless you increase conservatism on the shearwater to more closely match.

Gauge mode and tables if you need the backup early in the dive? Adjusting suunto conservatism to more closely match is only done by dangerous technique.

Regards,
Cameron

 

[tomfcrist]

I use an oceanic dinosaur as a backup bottom timer in addition to my Shearwater. I write down my contingency plans in my wet notes...but I've never needed them. I have a Predator...and it has yet to fail. Keep fresh batteries in it, lube the Oring...they are fairly bullet proof.

 

[TT_Vert]

What do you mean adjusting conservatism? I have it on the suunto on the least conservative now and it's far from liberal vs. any other computer that a buddy has dove with. I don't think I could make the suunto even remotely as conservative as the least conservative settings on the suunto. Sounds like a political discussion now and I'm not sure if what I said makes sense. It does to me at least....

Dave

 

[northernone]

What do you mean adjusting conservatism? I have it on the suunto on the least conservative now and it's far from liberal vs. any other computer that a buddy has dove with. I don't think I could make the suunto even remotely as conservative as the least conservative settings on the suunto. Sounds like a political discussion now and I'm not sure if what I said makes sense. It does to me at least....

Dave

The shearwater can be adjusted very conservative if needed by adjusting the GFs in technical mode.... Probably not the solution you want...

Adjusting alternatively a suunto beyond it's least conservative setting is dangerous.

Perhaps sell it to a diver who would appreciate the suunto algorithm?

Regards,
Cameron

 

[TT_Vert]

Tomfcrist- Care to elaborate on contingency plan? If I set my suunto into gauge mode it'll monitor present/max depth, time and water temp. Are you saying upon computer failure abort that dive and then switch the suunto to dive mode and use that for remaining dives? If so, the suunto will not let you switch modes until nofly time is up .


Northernone- definitely not going to make the shearwater conservative that is why I got it to get rid of the burden of the suunto algorithm. I don't even know how you can adjust conservatism beyond the least conservative pre canned setting (P0) on the suunto. That is possible? Even if just to prevent me from locking it out would be great. I could always switch whatever setting would allow that back to use it to continue diving, albeit at a much more conservative level. I could at least continue diving.
Dave

 

[uncfnp]

I dive a Shearwater and a Cressi. The Cressi uses a similar RGBM algorithm as the Suunto. The Suunto will not make a good back up to the SW unless you set the SW very conservative. In fact, the high conservative option in the recreational setting will still lock out your Suunto on repetitive dives if you approach the Shearwater NDLs.

 

[northernone]

I use a planning tool to generate contingency dive plans and write them onto wet notes. Shorter and longer dives than the intended profile. If my computer dies I use my back up on gauge mode to carry out the contingency plan (custom cut tables)

 

[TT_Vert]

Thanks guys. I sort of suspected the suunto would be a paperweight or perhaps a gauge but since I cannot switch from gauge to computer mode anyway for 24 hours it seems pointless to even have it as a backup. I only do rec diving so I suppose I'm going to have to just fall back to my wife's perdix if my petrel fails. We always enter and exit together and she is always above me without exception so I guess that's as good a "contingency" as any...

Dave

 

[tomfcrist]

Tomfcrist- Care to elaborate on contingency plan? If I set my suunto into gauge mode it'll monitor present/max depth, time and water temp. Are you saying upon computer failure abort that dive and then switch the suunto to dive mode and use that for remaining dives?

Nope. Leave it in gauge mode. Revert to custom tables(contingency plan).

If your intention is to use the sunnoto as an actual dive computer...you are doing something that doesn't make sense. If you want a backup computer, it has to have either the same decompression algorithm or a very similar one to the primary computer that you intend to follow.

Personally, I'm going to write the dive plan in my wet notes every time anyway. I like the ability to revert to what works when all my technology fails. (Which will probably happen eventually)