Primary hose length

[kelemvor]

I switched a few dives ago to using a necklace for my octo. I did it because I was constantly finding that no matter how I secured the thing it would come loose and dangle. Also, the hose just seemed to loop around me and contributed to me feeling cluttered. I route the hose under my arm, secure it with some bungee, and I hardly know it's there.

Well, the more I've read about this setup I've come to know I was doing a few things wrong. I understand that in a donation scenario I need to donate my primary and breathe octo myself. No problem - I've practiced breathing the octo several times (and replaced it as a result). I've also been reading that the primary should be extremely long.

1. How long should it be?
2. How should I route it so as not to reintroduce that "clutter" problem I'm trying to avoid.


For those of you who dive a setup like this, do you ever get a hard time from boat ops or divemasters regarding it? Any other potential problems I'm not immediately thinking of?

I ask because I'm finding my 8" dia steel tanks are more of a problem than I expected. I've never had to not dive, but they don't fit in most tank holders I've encountered so I have to do everything different from every other diver on the boat. I don't want to end up with another oddball configuration that doubles my trouble topside.

 

[rhwestfall]

The 7' primary was established with divers in restrictive environments, essentially allowing them to share gas while swimming in single file formation (cave/hallway). In the open water, anything from 40" or more seems to work. I really depends on how you want to route the hose.

As to being the "oddball", it is more of how you discuss what you are doing with your buddy. The concepts are not that abstract, but make sure you know what you are doing....

 

[TSandM]

A variety of hose lengths will work, but how you route the hose and what you need to do to make the setup work differs.

You can use a standard octo-length (36 or 40") hose. This you route under your right armpit, but you will need a 90 degree adapter where the hose meets the second stage, so that the reg will sit comfortably in your mouth.

You can use a 5' hose, which is routed under your right armpit, across the front of your chest and up over your left shoulder, around the back of your neck to your mouth. This length works very well for open water diving, as long as you are not barrel-chested or very broad-shouldered. (In those cases, the hose may be too short, and limit turning the head to the left.)

You can use a 7' hose, which is what cave and technical divers do. It is routed the same as the 5' hose, except that you either catch the hose under a light canister, knife or pocket at your right hip, or double the hose and stuff the loop under your waistband. Honestly, a 7' hose is a bit of a pain with a standard BC setup, and it is not really necessary for open water diving.

I have been diving a 7' hose since a few months after I got certified. I had one dive op in Australia comment on it, but not unpleasantly. (He said, "That's the setup wreck divers use, isn't it? Don't you worry you're going to strangle yourself on that long hose?") Otherwise, it has passed with comment, or at least any made to ME.

 

[lonebrave]

post removed...TSandM said it much better (and types faster than I do, apparently).

 

[lowviz]

Don't feel badly, I didn't even get to post...

 

[g1138]

Keep in mind when you donate your primary and breath off your secondary it's then called a backup, not an octo. Octo entails that you're willing or able to donate it. With backups you either aren't able to or it is just on such short a hose that it becomes extremely impractical.

There are different mindests and methods behind the primary donation in an OOA scenario, so it's not just training yourself to be able to donate the primary and switch to your backup, it's also being in the right mindset as well. You have to be set in a reactive rescue phase, not a passive "take any air source you like" phase. This means recognizing an OOA problem and donating before the situation devolves into a grab fest (ideally of course).

The longer hose also means easier underwater swims while connected to an OOA diver. You may want to do this instead of ascending immedietly if say you were in an overhead environment: cave, wreck, boating channel etc.
But of course in these situations gas planning is absolutely critical, prior to getting into the water.

You'll want to attach a bolt snap to your primary hose if it's longer than 40in because otherwise it will drag on the ground as you walk.
I'll clarify for TSandM. You have 3 choices:

1) 40-44in primary on 90 degree angle adapter
2) 5ft primary
3) 7ft primary

These are paired with a bungee backup on a 22-24in hose.
Option 1 only works with hoses 40in-44in. Any shorter and you won't be able to turn your head up and to the left with your primary in your mouth. Any longer and you'll have an extreme bow of hose coming below your waist. 36in is way too short for this configuration, it does not work; this coming from a person with very narrow shoulders and a tiny body profile. Sherwood makes a reg that comes in this configuration, called the Maximus, and they sport it with a 38in hose, for reference. Having that little extra with the 40in makes it more comfortable both for use and OOA donation; though if I could do it again I would still recommend 44in for that extra distance if needed.


There are no videos I can find of donating a reg in this setup, but the basic guidelines are the same. Hold the hose when you donate, but use your index finger and thumb to swivel the reg around to face the OOA diver. This keeps the purge clear if they need to use it.

One big downside to the angle adapter option is it adds a lot of weight to the reg, so you will be at minimum clenching your teeth lightly against the mouth piece. With the 5ft, 7ft or usual reg setup, you are able to hold the reg in with just your lips and a longbite mouthpiece if need be throughout your dive. The angle adapter just adds enough weight to make this real strenuous.

Unless you're sporting a BC with a nylon 2in waist band (so like Scubapro Litehawk, Zeagle Express tech, backplate/wing) I wouldn't go with a 7ft hose, because you won't be able to tuck the excess loop securely. I would instead advise getting the 44in hose w/ angle adapter.
Here's a picture of the setup, you can find pictures and videos of the 5ft and 7ft setup online; look up "DIR S-drill" on youtube:
*note the website: DiveRite states this diver is using a 40in primary, and there's really no slack to speak of. So when I say it's "blanket-answer" bare minimum, I pretty much mean it from experience.
For some reason the hose doesn't seem to be connected to the tank, but you really only get an inch to 3/4in of slack under your armpit.

And most operators I've encountered won't give you any trouble as long as you look confident in utilizing your setup. Dropping your 7ft primary on the deck or saying "I'm using it because it's a tech setup" is usually grounds for a more in depth conversation with the boat crew. For me, red flags only pop up if the person really has no clue why they're using that setup, simply because it requires a bit more familiarization and skill to manage. It's nothing anyone can't handle with a mentor and 30min pool session, but it's not something you want to jump into cold on an ocean dive.

 

[kelemvor]

Wow, thanks for all the great input guys!

It sounds like I will end up with the 40-44" primary and 20-24" backup. I was trying to find more info on the diverite site after reading g1138's post and came across this gem:

[video=youtube_share;dSKGKG-8zRA]http://youtu.be/dSKGKG-8zRA[/video]

FWIW, my BC is a diverite Trans Pac (it says, but doesn't look like anything on the diverite site, including retired) with a steel backplate and a rec exp wing. The wing also differs from what's on the site since it doesn't have any bungee around it. I've added some ditchable weight pouches to it, and bolted a small knife onto the top of the left weight pouch. I also carry a diverite thigh pocket so I could stuff some danglies in there (whistle, spare mask, sausage).

I have no plans to engage in cave diving; and probably won't do anything technical for years. I went with the bp/w mainly because I'm losing weight and didn't want to replace my bc left and right. The price was a nice bonus.

 

[highdesert]

One big downside to the angle adapter option is it adds a lot of weight to the reg, so you will be at minimum clenching your teeth lightly against the mouth piece. With the 5ft, 7ft or usual reg setup, you are able to hold the reg in with just your lips and a longbite mouthpiece if need be throughout your dive. The angle adapter just adds enough weight to make this real strenuous.

.......................

Here's a picture of the setup, you can find pictures and videos of the 5ft and 7ft setup online; look up "DIR S-drill" on youtube:
View attachment 155320*note the website: DiveRite states this diver is using a 40in primary, and there's really no slack to speak of. So when I say it's "blanket-answer" bare minimum, I pretty much mean it from experience.
For some reason the hose doesn't seem to be connected to the tank, but you really only get an inch to 3/4in of slack under your armpit.

A lot of good info in your post, but I have two issues that I might disagree with ...

1) I don't accept that a 90 degree adapter alone is such a weight burden that it makes holding the second stage in the mouth uncomfortable. If someone finds that to be the case, perhaps their mouthpiece simply doesn't fit well enough, on their long hose is still too short. I agree with the 44" length, personally.

2) In the photo shown, the diver will be donating his "primary" second stage, the one in his mouth, and lifting his necklaced octo to his own mouth. A panicked diver in an OOA situation is going to zero in on yellow (or so we're taught), and in the case of the diver in the picture, that diver will go for the wrong second stage, on the shorter hose, which is routed under the long hose. I've reversed the purge covers on my setup so that an OOA diver will go directly to my long(er) hose, not the necklaced one, and not have to be literally head to head during buddy breathing. If there's something I'm missing here, I'm glad to have someone fill me in!

 

[exposure]

Realy nice exchanges. I would add one thing. Brief your buddy before the dive, first you'll teach him new thing and you'll have less surprise in OOA scenario.

I am diving 7' in all non teaching dives for consistency between tec and rec dives. OOA scenario is really panicking position, so i would not give a reg that i am not sure it is working. The best way to do that is to give the one you breath

 

[ams511]

Wow, thanks for all the great input guys!

It sounds like I will end up with the 40-44" primary and 20-24" backup. I was trying to find more info on the diverite site after reading g1138's post and came across this gem:

[video=youtube_share;dSKGKG-8zRA]http://youtu.be/dSKGKG-8zRA[/video]

FWIW, my BC is a diverite Trans Pac (it says, but doesn't look like anything on the diverite site, including retired) with a steel backplate and a rec exp wing. The wing also differs from what's on the site since it doesn't have any bungee around it. I've added some ditchable weight pouches to it, and bolted a small knife onto the top of the left weight pouch. I also carry a diverite thigh pocket so I could stuff some danglies in there (whistle, spare mask, sausage).

I have no plans to engage in cave diving; and probably won't do anything technical for years. I went with the bp/w mainly because I'm losing weight and didn't want to replace my bc left and right. The price was a nice bonus.

I was going to recommend this video but you already found it. They also have a video showing the long hose. The beauty of this arrangement is that if you want to go to technical diving then you just need to replace the 40" hose with a 5 or 7 foot one.