ball swivel question

[StSomewhere]

What about that 45 deg solid fitting/longer hose under the arm idea? Thinking about the mechanics of it, I realize with the hose in a more or less vertical position, there would be less side to side bending resistance (I think).
So how long should the hose be?

IMO the 90° elbow is nicer than the 60° +/-, YMMV. If you are routing the hose underneath your right arm, 40" is about perfect and isn't a hard hose length to find since thats the same hose that many tech divers use for stage bottles. If you combine it with the bungeed backup (instead of an octo) its about perfect.

 

[TeddyDiver]

Hi all,
Went diving for the first time in a couple years last Saturday, and during the dive I was reminded how my second stage hose caused me to have to bite down harder when turning my head. Not really a big deal, but at the same time, kinda annoying.

Vote for long hose with DIR routing...

 

[fishoutawater]

Does make a lot of sense.
Also been thinking about bungeeing my secondary around my neck. But it's one of those Sherwood slim jobs. I did play with it a little the other day. Had no problem finding and using it, but putting it back in its holder was difficult.
I'm gonna end up totally refitting one of these days. bp/wing, new regs, (not sure what kind yet). There seems to be as many models as there are opinions.
And another question. In DIR, is the secondary another primary, or is it supposed to have a higher cracking pressure?

 

[Doc Intrepid]

It's another primary. You may be on it for quite awhile. They may often be de-tuned, however, to avoid freeflow...

 

[fishoutawater]

Thanks Doc. So what are the equipment considerations for wreck penetration besides torches and reels? Does that require an even longer primary hose?
Wreck diving does interest me.

 

[Doc Intrepid]

Thanks Doc. So what are the equipment considerations for wreck penetration besides torches and reels? Does that require an even longer primary hose?
Wreck diving does interest me.

Fish,

At the risk of hijacking this thread ( ), you use the basically the same equipment configuration for wreck penetration as you would for cave. Wrecks are very similar to caves, except for a couple important things...first, they rust. This results in consequences that caves don't have. Second, wrecks degrade over time...crap hangs down inside them, insulation, electrical cables, wiring, hatches can close at bad times, rails or walkways can fall down and block passages, etc. Mostly caves are found in the same condition going out as when you went in. In general wrecks offer a more dynamic environment, while caves offer a more static environment. You can stage gas in a cave, for example. You wouldn't want to do that, generally, in the open ocean diving a wreck. You hump it with you instead.

You use the same hose either way, a 7' hose, which allows two divers who are sharing gas to negotiate a narrow restriction where they must pass through it one at a time in single file. The out of gas diver must swim ahead of the donor diver through the restriction, which is why the hose must be able to reach from the second diver's manifold to the mouth of the first.

The few main differences in equipment include things like in a cave you don't need a liftbag or SMB. There is no place for it to go. In the open ocean, the SMB/reel is your life line/drift deco line in case of numerous difficulties which include wing failure, current sweeping you from the wreck, loss of the anchorline, disorientation, etc. There are other equipment variances, e.g. line arrows, cookies, and other cave stuff, but you get the idea.

Here is a link to a site that offers a number of articles, photos, and other documentation regarding technical configurations and rationale. If you've not read it previously, its a decent place to begin:
http://www.wkpp.org/articles/Gear/newgeorge.html

Hope this helps.

And now, back to your regularly scheduled swivel-joint discussion!

 

[fishoutawater]

Not a hijack at all Doc. Much appreciated. Think I'll skip the swivel-joint idea and go for the 40" hose, 90 deg fitting, and custom mouthpiece for my present rig. Think it'll work just fine for what I'm doing now.
Thanks for the link. Haven't seen that one yet. Lots to learn.

 

[darkstar]

I would be interested to hear who has actually witnessed a ball swivel failure. We've heard one first hand account and I wonder just how common it really is.

 

[liberato]

M&J Engineering stuff is available a little cheaper at Tech Blue...

Tom, the two swivels look significantly different:
MJ Engineering
Tech Blue

Which one do you have?

 

[flyguy]

One of the deciding factors about buying my Atomic B2 was the fact that it came with a swivel and it apeared well manufactured and durable. It makes a HUGE difference in decreasing jaw fatigue.

I'm a rec diver and I'm always with a group so the benefits outweigh the relativaly minor risk.