octopus in public safety

[dandecraene]

We're looking at streamlining our setup for our fire district dive team. With a completely redundant back up system (19 cubic foot pony with its own first and second stage) is an octopus really necessary? Does the risk of silt building up an causing free flow out way the benefit of the rare occurrence of needing the octo over the pony?

Dan

 

[VooDooGasMan]

dan I have not used this device I just ran across it lately.

Free Flow Control Device

 

[k ellis]

the answer to your question is yes you still need it. The fact is gear is gear and no matter how prepared we make ourselves we are always at risk to forget something. Especially if its an emergency situation. the silt building up is not really concern if you stay up to date and maintain your gear. if it is drug through the much then have it inspected.

Sorry have to run so the answer is alittle short but yes more safety net is better

 

[k ellis]

dan I have not used this device I just ran across it lately.

Free Flow Control Device

this device is used on a low pressure inflator hose to prevent free flow that could cause a BCD to over inflate. If the inflator valve were to get stuck open you would just slide this device into its closed position rather then having to fight to remove the hose from the inflator

 

[Thalassamania]

The pony is every bit as likely to suffer the same problems as the octo, and vice versa. The question is where do you store the second stage and what is your protocol for the valve on the pony. For example: there is no reason that an aux. on a necklace that is supplied by a pony must be handled any differently than an aux. on a necklace that is attached primary first stage or, for that matter, your secondary first stage on a set of doubles. An alternate approach is to right your ponies as stage bottles and thus have three second stages. I think that all of these solutions are workable, though some may argue about the fine points. The critical item is to get team agreement to all handle things in the same fashion and then drill the hell out of the system. BTW: if there are nearby teams that you often work with you might want to see what they are doing and either follow suit or at least reach a meeting of the minds ... standard procedures are your friend.

 

[DevonDiver]

this device is used on a low pressure inflator hose to prevent free flow that could cause a BCD to over inflate. If the inflator valve were to get stuck open you would just slide this device into its closed position rather then having to fight to remove the hose from the inflator

No. You can get them for regulators too.

Yes. It is a scary thought.


@Dan: First caveat - I'm not a public safety diver, so take this advice for what it's worth. My opinion is determined by how you configure your equipment. If you use 'H' or 'Y' valves on your main cylinder, then there's a lot of benefit to having an AAS. You have another redundancy source, albeit not completely separate, that increases your self-rescue options from 2 to 3.

I think that there's some good methodology to be shared from cave and wreck divers (which I do). They also regularly operate in low-viz, high silt and likewise value clean, absolutely functional configuration. Necklace stowage of an AAS is an obvious strategy (as Thal pointed out). Use of appropriately sized double-tanks, with isolator valve, is another. In the UK, back-mounted isolated doubles are very popular as a replacement for single cylinder - typically twin 6-8L tanks. Not much more bulk/weight than a single large capacity tank, but the benefits of complete redundancy and flexibility. Especially when used with a 'long hose'.

Would you ever envisage having to 'pass-off' the pony bottle as part of a rescue procedure (victim trapped underwater?). If so, you'll need that AAS option for yourself and your team. There's a lot of benefit from having the pony 'slung' rather than back-mounted for that reason.

 

[dandecraene]

Thanks for the input so far.
Here's a little background on our gear.
Equipment maintenance is of course paramount to our divers' saftey. Every piece of equipment is cleaned after each use and annually (or more often) inspected. We have had two training occurrances where the second stage octo has gone into free flow because of silt. On one of those dives, the diver staged his octos on a holder on his right shoulder. The second time it happened the octo was staged on a holder near the diver's right hip. Crews reported that the octos did not dislodge in either circumstance.
The second stage reg on our pony setup is staged on a cave necklace.
We have a few views on the subject on our team. First: lose the octo, the free flow risk out weighs the need with the pony set up. Second: keep the octo, there is nothing wrong with have redundant redundancy. Third: move the octo to the inflator hose keeping it closer to the diver's core.
In any circumstance, I can assure you we will be training continuously with our gear as is or with whatever changes we make.

Dan

 

[Firegirl]

We dive with a 80 cuft with and a 19 cuft with its own 1st & 2nd stage held by a neck strap around the divers neck. It is not necessary to have a octopus from your 80 cuft. The secondary air source with it's own regulator is far more superior than depending off one single air source for public safety diving. A octopus will be in the way and will drag in the mud if you do not have it well stored.

 

[Firegirl]

We have had problem with the octo being on the BC hose with it dragging in the mud and free flowing....we got rid of all octos and BC 2nd air when we went to the 19 cu ft with regulator

 

[ditch-diver]

So if I am picturing this correctly, you have your main breathing gas with an octopus plus a separate, redundant pony bottle with it's own regs?

You already have an octopus, the fact that it is attached to its own first stage and own tank is just a bonus. Think about it, the octopus came around with the mind set that every diver in the water would have a completely redundant set or gear to breathe off of in the event of a major failure. The diver would have his own equipment plus the redundancy of his buddy's dive gear with an octopus. (Whether the donor or receiver breathes off the octopus is a moot point for the purpose of this discussion) That level of redundancy remains today and in many cases has been raised by divers wanting to be self-reliant and carry their own redundant set of equipment (like your pony bottle system). While it is nice to have in the sport diving world and more necessary in the tech/cave world, it is in the PSD world where you are in the water alone a majority of the time and need the separate redundant system that is not present in the form of a buddy's equipment.

With the system you have described, you have met and surpassed a level of security offered by an standard octopus off of the main tank. There is no reason to have it still there. If there was we'd all be sport diving with two or three octopuses (octopi??) just to be super-safe and we just don't. Surface Supply divers don't wear and octopus on their bailout because the chance of it malfunctioning and draining the bailout is greater than the chance of the band-mask/helmet failing. You said it yourself, the risk outweighs the benefit with the pony system present.

Remember in PSD you need a clean configuration.., more is not always better. Stay away from stuff that is not of the utmost importance, like a second octopus or long hoses.


How are you carrying your pony? Back mounted? Slung to pass off? Most teams I have dealt with over the years have tried to stay away from slung tanks on searchers as they tend to be poorly placed during the zero-vis/belly crawling searches. Some will back mount the searchers and sling a pass off bottle on the rescue diver/standby-diver/90% diver or whatever you call them.

The important thing is get a set up a gear configuration, make it a standard for the whole team so that everyone is exactly the same and train, train and train some more with the new config until it is second nature