Question Redundancies

[went_postal]

For recreational diving, you should be able to survive the failure of ANY piece of gear. If you are not reasonably confident that this is true with your particular set of equipment, then you need additional training and/or a change in your configuration. This is not a flippant comment, it really should be a guiding principle in your diving as you move forward.

I pretty much always carry a pony bottle and a single, console mounted dive computer, compass and mechanical pressure gauge. I also wear a watch.

I've had my computer become unusable many times while diving. For recreational diving, this is more of an inconvenience than a significant danger. I think it makes more sense to concentrate any redundancy efforts towards risks that present significant dangers - such as air supply and a means of establishing buoyancy - those can kill you, not a loss of data.

I don't look at it as just loss of data.

If you are using your computer to monitor your depth and air pressure... if that unit stops doing that for whatever reason. Sure... end the dive. But now how do you know when you've reached a safety stop depth if you don't have anything reporting your depth?

That was more my point. It was less about not having the skills... and more about having backup systems that allow you to continue to function safely to exit the water.

Again... I could be WAY overthinking this.

When I was on the FD I got my certification and training from a place other than the department I was working at (long complicated story). I carried a TON of stuff in my turnout gear "just in case." One day my chief picked up my turnouts and started screaming at me about how heavy it was and all the sh*t I had in it. But... on more than one occasion my having stuff on me saved time by not having to run back to the rig for something every five seconds.

I carried a set of spanners on me. Did I need them? no... all the rigs have them. But needing spanners on a hose 150-200ft away from the rig doesn't help you.

I carried lineman's pliers for cutting car battery cables. Did we have bolt cutters on the rig? Sure... they are WAY heavier and again... the rig is away from the scene when seconds count.

I also had a bailout bag (rope bag with descender) and some webbing for dragging someone out... both things you are not going back to the rig for.

Did I use all that stuff all the time? Nope. Sometime I just had a heavier coat than the guy next to me... and that was fine by me. I cannot pre-plan for every contingency but I can prepare for some things more or less reasonably.

I am also that guy that has jumper cables, toolkits, and first aid kits in all my vehicles.

So what I've pretty much gotten out of this thread is:

Everyone does their own thing. You do you and make sure whatever gear you have is in good service.

 

[jadairiii]

Don't forget the depth gauge.

Correct, but even if you dont have an extra, and you are a brand new diver, good chance you are in 40' or less on a hard bottom, you could dive without one! Many times I've done beach dives (35' max) with a compass, spg, and a watch.

 

[inquis]

how do you know when you've reached a safety stop depth if you don't have anything reporting your depth?

I'd actually say you're "under" thinking it in this particular scenario, as there are various options. In many places, you can see the surface, so judging safety stop depth isn't difficult. If vis is bad enough that you cannot see the surface, then you can deploy a DSMB -- your buoyancy will thank you for the visual reference and you can put a knot at 15 ft for depth info. There's also the near-certain probability that your buddy's depth gauge still works.

 

[grantmac]

It's an NDL dive, the stop is optional. Just get shallow for a little while then surface.

 

[RIHappyDiver]

Sure... end the dive. But now how do you know when you've reached a safety stop depth if you don't have anything reporting your depth?

My wife struggled with this concept when she was a new diver. It seems that OW instructors are maybe putting a bit too much emphasis on safety stops, to the point where new divers think that they are required. They, absolutely, unequivocally, are not! They are highly recommended, but not required.

To @inquis ’s point, if you feel better doing one, great. Guesstimating your depth and time is absolutely acceptable. Also, he’s right about your buddies computer going belly up at the same time. Highly unlikely. This is the one situation where I feel it’s OK to use your buddies computer.

To @grantmac ’s point, you’re a new diver, you shouldn’t be anywhere close to a deco dive. In a situation where you have experienced equipment failure of any type, it is OK to go, slowly, to the surface, passing your safety stop. This is why they (hopefully) still teach watching your bubbles on assent.

To answer your question on redundancy, I dive with 2 computers and an spg. I don’t have a depth gauge. I’m questioning my use of a second computer for local dives, as I’ve never done a rec dive in this area that was more than 45’. I carry 2 cutting devices, a whistle, a signal mirror and a dsmb. A PLB is added for boat dives. When solo diving I add a pony, though, again, locally I’m not sure that it’s needed. But it makes my wife happy if I have it.

As a person who wants to cover all possibilities, I understand where you’re coming from. However, it is possible to carry too many items, to the point where it becomes a liability.

Erik

 

[bradlw]

My wife struggled with this concept when she was a new diver. It seems that OW instructors are maybe putting a bit too much emphasis on safety stops, to the point where new divers think that they are required. They, absolutely, unequivocally, are not! They are highly recommended, but not required.

just last weekend down in the Keys my wife was doing the same thing...and critized me for blowing the safety stop. I pointed out that the entire dive was the safety stop...at about 20ft. That's an exaggeration for course, we did get down into the 30's a bit.....

This is why they (hopefully) still teach watching your bubbles on assent.

they didn't for my family's recent OW class.
They just told them to look at their computers...but never the whole time told them what any of the indiactions on that rental computer were trying to tell them....It was just going through the motions. "look at your computer for the ascent". yes ma'am...I have no idea what any of it means...but yes ma'am!
That was my biggest criticism of the class!

I’m questioning my use of a second computer for local dives, as I’ve never done a rec dive in this area that was more than 45’.

Yeah, for super shallow stuff, I agree. Maybe a little more streamlined without the second computer. I lean towards wearing it, because if one of my computers goes kaput on the first dive, I can just carry on into the second dive because my backup will have the proper data to compensate for teh repetitive dive group and surface interval.

 

[MB NZ]

There comes a point where carrying more gear underwater to cover every possible eventuality becomes a hazard in itself. Where you draw the line is specific to your own circumstances.

 

[johndiver999]

I'd actually say you're "under" thinking it in this particular scenario, as there are various options. In many places, you can see the surface, so judging safety stop depth isn't difficult. If vis is bad enough that you cannot see the surface, then you can deploy a DSMB -- your buoyancy will thank you for the visual reference and you can put a knot at 15 ft for depth info. There's also the near-certain probability that your buddy's depth gauge still works.

yes and the fact that the op mentioned difficulty with a safety stop shows his unfamiliarity with the issue. Rather than a safety stop depth, a more critical issue is how to perform an ascent at the correct speed (without a computer).

In the event of a computer failure (during a deep recreational dive) one might want to be able to deploy an smb from depth and then slowly wind themselves back up to the surface.

An smb on a reel or spool, provides a considerable degree of safety and can be very helpful in several "problem" situations.

When it comes to redundancy, the diver needs to carefully think about what kind of issues they will be able to handle (and which ones they won't - also ones they deem so unlikely that they are not worth worrying about).

The point is that this is a personal decision and the diver should be able to clearly justify their decisions (at least to themselves). Every single piece of redundant gear comes at a cost of added complexity and also an increase in the probability of a gear failure. It is not "maintain your gear and bring whatever you feel like".

 

[OTF]

A DSMB+spool with a knot in the line at 15 ft can mark your safety stop depth as a backup, and help you stabilize there by giving a visual reference or physical thing to hold.

A DSMB + spool is a really great thing to have, a simple tool useful for probably a dozen other totally different scenarios from rescues to navigation. But new divers need to train and practice to use them properly. It's a simple thing but screwing it up can drag you to the surface.

 

[Eric Sedletzky]

What happened to "Follow your smallest bubbles"?
That is the very most basic stuff.
Do they not teach that anymore?
And if you're within your NDL (this is a basic forum) a 15' stop is not mandatory.