CCR bailout scenarios

[emmbee]

If your dil is hypoxic, this device will drop the p02 from your diluent even further over the course of 4 breaths and you'll be out cold before you get back to a depth where you can switch to 02.

GEM manual says they're happy to give you 4 breaths from 32% all the way to the surface, so your 10/70 will get you to 20m?

Sounds like you'll need to carry a range of tins anyway

If you got those large inboards, then you only need one extra intermediate and this, and that would get you home on your own?

[Stephen McMullan]

Yep 20m is not 6m or even 10m 

Likewise if you wanted to get out of the water / complete out your deco within a reasonable period of time you'll be wanting to gas switch as you ascend and given the length of time we spend between 40m->20m on the ascent you'd want to be on something a bit richer than 10/70 before you get to 20m!!!!.

Now if you're carrying oc deco gas thats grand (but in my case unlikely) or you're still relying on drops. Where I see this device solving a problem is extending my deep and intermediate (which is an issue currently as running out is quite possible if you're bailing out unassisted) until I can get access to rich gas for deco from above.

Our current bailout strategy involves 5 gas switches from depth to the surface so I don't think onboards + 1 intermediate will cut it. It might do from 60m-70m ok but thats not what I'm considering.

[Stephen McMullan]

Our current bailout strategy involves 5 gas switches from depth to the surface ...

I've been reprimanded by the team leader who informs me that apart from the two offboard bailouts the drop set has cylinders at 80m / 60m  / 45 m / 30 m / 21 m / 10 m / 6 m and I'll need every one of them so "slightly" more than 5 

I'm must have been looking out the window (or more likely honking over the side) during the safety briefing 

[Scubadec / Dec Hanniffy]

Our current bailout strategy involves 5 gas switches from depth to the surface ...

I've been reprimanded by the team leader who informs me that apart from the two offboard bailouts the drop set has cylinders at 80m / 60m  / 45 m / 30 m / 21 m / 10 m / 6 m and I'll need every one of them so "slightly" more than 5 

I'm must have been looking out the window (or more likely honking over the side) during the safety briefing 

How do you get to the dropset cylinder at 80m? Is the bottom attached to the shot line too? or are they fed down your yellow bag line?
Im presuming dropping them beside your yellow bag, and hoping you see them is way too mad an idea.....

[Stephen McMullan]

Yellow bag goes up. Skipper / surface support tie the end of the drop set to the top of the dsmb line, deflate the bag and send it in. Diver reels in in order to find the drop line.

Stewie claims it works as he did a trial run. BUT that was super Stewie...we must do some more trials.....

Nah the diver would never see it if you tried to aim beside and hope for the best. 80m is a long way down and the set is negative but not hugely so. It would drift out of sight by the time it got down to the diver.

There are other techniques that work with shallower drops (e.g. clipping to the dsmb line and sliding it down) but don't really work on deep drops as they cause entanglement on the way down etc.

Not a perfect solution but the best we've got at the minute. Its still a work in progress.

[baza]

We have 3 different drop sets for each trip. A quick drop with a 80 m and 60 m gas. The second drop is loaded with 45 m / 30 m and 21 m. Then the shallow drop will have 21 m / 10 m / 6 m. We normally have a few more 50% / 80% / 100% on the boat too that can be brought down to be diver by rope or support diver.

When the yellow bag appears on the surface, the skippers first task is to deploy the deep drop set by attaching it to the yellow smb and deflating the yellow to send it all back down to the diver. This does two things; one allows the diver to recover their yellow for a second deployment and ensures the diver has a line connection at all times with the drop set. The skipper should be able to get the quick drop into the divers within 5 mins (Max 10 mins) of the bag hitting the surface. The skipper then has a little more time to drop the second drop set as the diver ascends. The critical time is from when the diver first bails out until they get to their first drop set at their first stop.

The diver can re-deploy the yellow if they want the next drop, but more than likely the skipper will automatically send in the second one before it comes up. The support diver (if available) is then deployed after the second drop set is deployed. They will likely check the diver and bring down another mid-level stage or two. The final drop set is then sent in if required. The support diver brings extra shallow stages depending on how long the shallow stops are going to be.


We don’t store much on the shot / lazy / trapeze for various reasons, mainly the fact that the diver is likely not to be able to get back to the shot all the time and might have to bag off from the wreck. There are also a few issues with strong currents / deployment of stages on the line by support divers. The other reason would be lack of extra drop gas cylinders as we use up a lot on the drop sets / extra pile on the boat.

I hope that helps. This is only our approach. There are lots of other ways to go about this and we are constantly updating and reviewing our system.

Chat soon,
Barry

[Scubadec / Dec Hanniffy]

Ah yes! I forgot Surface support! I was wondering how someone from a boat like the Ros Guill would manage to get them accurately to you... Iv Seen people mention having Dropsets attached to hoola hoops for skippers to drop down over the yellow bag!
Your idea sounds like the best option. But thats hoping that only one diver needs the dropset. or am I missing some easy way of getting a second diver to find the dropset?

[emmbee]

Our current bailout strategy involves 5 gas switches from depth to the surface so I don't think onboards + 1 intermediate will cut it. It might do from 60m-70m ok but thats not what I'm considering.

Fair enough, just wondering. Quick calc looked like for 30 min (25 on the bottom) at 100m on 10/70 @ 1.3, this thing (1:4) might get you out on two 7L inboard + 1 extra 7L, even accounting for 2L spent from the inboards, at GF 30/80. Of course the deco was wrong (OC, not SCR).

Ta

Matthieu

[baza]

Two different divers having to bail out from more than 100 m on the same dive... Thats some very bad voodoo!!! I'd want to be the first to get my bag on the surface and hope the skipper liked my name on the bag more than the other guys Maybe even attaching a few euro's on the top of the bag might help too....

You couldn't carry enough drop sets / gas to cover all divers in the water. We work on the basis that one critical failure requiring a full bailout per dive. To be very honest, bailing out from below 90 m is all about team planning and isn't to be done too lightly. It would need to be something terminal like a FULL loop flood or CO2 issues to force me off the loop. I have friends who have bailed out while on ascent from 135 m due to a full loop failure (Meg - dont believe all the hype in the video's  , they do flood so bag that we stop working). The key is to have drops and a good team around you to cover you in the gap between surface support and the drops sets.

[Stephen McMullan]

Iv Seen people mention having Dropsets attached to hoola hoops for skippers to drop down over the yellow bag!

We're worried about things like the hulahoop tangling on the smb line and hanging up the drop set beyond the reach of the diver. Not such an issue with shallower drops...

Your idea sounds like the best option. But thats hoping that only one diver needs the dropset. or am I missing some easy way of getting a second diver to find the dropset?

If you've two divers on yellow bags a distance apart well.....when I presented that scenario to Jeff Cornish / Darkstar in 2006 as a surface support / shallow cover diver he told me that would be a "very tough day at the office".

It can't really be dealt with. There's only really one deep drop set. This is as much to do with space onboard the boat/available resources as anything else.

We'd be kinda hoping they had buddies around them that could at least help get them back to 25m or so and then cobble together something from the spare 50% and 02 onboard.

Not a good scenario. 

[Scubadec / Dec Hanniffy]

Thanks lads!

[Stephen McMullan]

Our current bailout strategy involves 5 gas switches from depth to the surface so I don't think onboards + 1 intermediate will cut it. It might do from 60m-70m ok but thats not what I'm considering.

Fair enough, just wondering. Quick calc looked like for 30 min (25 on the bottom) at 100m on 10/70 @ 1.3, this thing (1:4) might get you out on two 7L inboard + 1 extra 7L, even accounting for 2L spent from the inboards, at GF 30/80. Of course the deco was wrong (OC, not SCR).

Ta

Matthieu

10/70 -> intermediate -> 02 still strikes me as a very harsh profile for a bail from 100m after a 30minute bottom time. Apart from gas quantities you'd need to take a good look at ICD risk and what your CNS would be after the profile.

By the way if I was on OC bailout with limited gas supply you can forget about 30/80 GFs. It would be closer to 100/110  on the ascent

[Turbo]

We have 3 different drop sets for each trip. A quick drop with a 80 m and 60 m gas. The second drop is loaded with 45 m / 30 m and 21 m. Then the shallow drop will have 21 m / 10 m / 6 m. We normally have a few more 50% / 80% / 100% on the boat too that can be brought down to be diver by rope or support diver.

When the yellow bag appears on the surface, the skippers first task is to deploy the deep drop set by attaching it to the yellow smb and deflating the yellow to send it all back down to the diver. This does two things; one allows the diver to recover their yellow for a second deployment and ensures the diver has a line connection at all times with the drop set. The skipper should be able to get the quick drop into the divers within 5 mins (Max 10 mins) of the bag hitting the surface. The skipper then has a little more time to drop the second drop set as the diver ascends. The critical time is from when the diver first bails out until they get to their first drop set at their first stop.

The diver can re-deploy the yellow if they want the next drop, but more than likely the skipper will automatically send in the second one before it comes up. The support diver (if available) is then deployed after the second drop set is deployed. They will likely check the diver and bring down another mid-level stage or two. The final drop set is then sent in if required. The support diver brings extra shallow stages depending on how long the shallow stops are going to be.


We don’t store much on the shot / lazy / trapeze for various reasons, mainly the fact that the diver is likely not to be able to get back to the shot all the time and might have to bag off from the wreck. There are also a few issues with strong currents / deployment of stages on the line by support divers. The other reason would be lack of extra drop gas cylinders as we use up a lot on the drop sets / extra pile on the boat.

I hope that helps. This is only our approach. There are lots of other ways to go about this and we are constantly updating and reviewing our system.

Chat soon,
Barry

Hi Barry
Just curious but have many of you practiced this bailout system from depth i.e. 100M ? and if so how did you find it to work? Also how does it compare to other bailout systems that are in use?

regards


cathal

[baza]

Our system has evolved over the years, but the core concept hasn't changed much, mainly we have just added to it and refined the mixes to give a better ascent profile and to shorthen the distance between cylinders / switches.

Stewie has done one full dry run of the deep drop coming up from a hundred metre plus wreck. We have used both shallower ones a bit more. Also members of the group have done a few from 60m or so. The system is bases very closely on the system used by Norman Woods and Co.

Normally when we are out diving the deeper wrecks, there isn't an option to do mock deployments as other divers on the dive may need it for real.

I know one of our main targets for next year is to do a few more dry runs early in the year. That and play around with the gases we are using on the line.

[baza]

As a comparison with other system. I've seem lots and been with groups that didn't believe in drop sets or carried so little that it wasn't much use. Bailout options are very personnel.

A lot is down to the diver to have as much or as little as the are happy with. For me, I still think we need more.