Doing AN/DP with FFM, Realistic?

[tbone1004]

The one thing I'm unsure of though is why he has a DTV with only one hose connected to it. Why wouldn't he have a second hose connected to it and still have a long hose for that 2nd stage dangling from his d-ring? Doesn't that sort of defeat the purpose of a DTV?

I would have a second hose on the right post that stays on block if I was using doubles for redundancy. If it was just for extra gas, then I would likely not have the DTV on in the first place.

 

[rjack321]

Wow that's a charlie foxtrot. That's a really good way to shut off your gas and have nothing to breathe while trying to shut down a post. And that's not even adding high FO2 deco bottles into the mix.

And he's going to a lot of effort to trap his long hose in the end - by routing the switch to FFM hose through his power inflator in the first example its definitely trapped. I can't tell if its trapped in the pool sequence or not but he should be stowing the long hose last regardless. He stows it first, not a good role model here.

 

[Addicted2H2O]

Just got back from Cancun/Cozumel and actually experienced a failure during my 2nd dive @ San Clemente in Cozumel. It was a shallow 25-30 ft dive but that also presented a problem. Back in January I had the main o-ring in my omni swivel fail during a safety stop in the lake. Not a big deal, I handled it. Well during my second dive on Tuesday I experienced the exact same failure. I actually had a spare mask and 2nd stage with me but mistakes were made. I had just finished capturing a nice moray on video and all of a sudden the o-ring let loose causing a free flow. I recognized the situation and knew what I had to do as I've practiced it many many times. Grabbed my octo and freed it from its holder in preparation for ditching the ffm. Disconnected the locking QD to stop the free flow then doffed the ffm and put my octo in place. 1st mistake.....didn't hang onto the ffm or my GoPro, which should've been secured around my arm and wasn't. Neither was a priority in that moment. Took a few breaths trying to calm down a bit while pulling my mask out of its pocket then proceeded to put it on and clear it. Guess I wasn't breathing out enough because I was inches from the surface when I cleared it. 2nd mistake made. As I was clearing my mask I realized I dropped the ffm and my GoPro so the plan was to go back down and grab them off the bottom. Luckily, two of the other divers with us grabbed them for me (Thanks if either of you is reading this!) Got myself neutral again and calmed down while clipping my ffm off to a carabiner I had clipped on a d-ring then pulled out my spare 2nd stage, connected it to my QD then switched over to that from my octo and stowed the octo back in its rightful place. Finished the rest of the 15 minutes of air I had left for the dive without incident but I was a bit shaken up afterward. I think more than anything I was a bit disappointed in myself for ending up at the surface like I did. I know I handled the situation exactly as I should've but being hard on myself the way I am and being a DM, I felt it should've gone a lot smoother than it did. So guess I have some work to do. And next order of business.....I think I'm changing the omni swivel out for a fixed 90 on the ffm.

I know this doesn't really have a lot to do with the topic of this thread but I know QD's, swivels, etc. (failure points) have all been mentioned and in analyzing the situation on the boat after it all happened this thread really came to mind and I'm not certain I even want to attempt AN/DP on ffm at this point. So you guys were right.

 

[tbone1004]

@Sh0rtBus after the first failure, did you put blue loctite on the bolt that holds the two halves together? That is the main reason for the ball swivels to separate. Everytime it rotates counterclockwise while under pressure it will back that screw out a little bit. Doesn't have to be a full rotation, just a small amount of movement is enough. Eventually it will come out if you don't have loctite on that bolt.

Glad everything worked out for you though!

 

[Addicted2H2O]

@Sh0rtBus after the first failure, did you put blue loctite on the bolt that holds the two halves together? That is the main reason for the ball swivels to separate. Everytime it rotates counterclockwise while under pressure it will back that screw out a little bit. Doesn't have to be a full rotation, just a small amount of movement is enough. Eventually it will come out if you don't have loctite on that bolt.

Glad everything worked out for you though!

Yes I did. I think the o-ring was just bad. Still, though, just to eliminate that weak point, I think I'm going to switch to a 90.

 

[tbone1004]

Yes I did. I think the o-ring was just bad. Still, though, just to eliminate that weak point, I think I'm going to switch to a 90.

If it is not a welded 90 like the one from Kirby Morgan, it will add some other interesting failure points, typically the bolt that holds the regulator side into the 90. I've seen those strip and blow out about as frequently as the o-ring separation.