The Backplate...

[IowaCaveDiver]

I read a post awhile ago where I think we all were debating the transition into sidemounting and how everyone is doing it and then it went into a discussion of different bcd's/rigs the people were using, and I recall a few posts saying that the backplate had to go...... it has sat on my mind for a few days and I ask why? I recently started sidemounting, and I have to say i've fallen in love with this form of diving, but I havn't given up my backplate/harness/wing and set of doubles, there are still many applications for them. Just thought i'd stir the pot and see what people thought on this... is the backplate/wing dying? Cave divers/tech divers like things simple and safe....how much more simple can you get than a solid steel backplate and a single piece of webbing with a wing... any thoughts?

[lonestarfl]

I read a post awhile ago where I think we all were debating the transition into sidemounting and how everyone is doing it and then it went into a discussion of different bcd's/rigs the people were using, and I recall a few posts saying that the backplate had to go...... it has sat on my mind for a few days and I ask why? I recently started sidemounting, and I have to say i've fallen in love with this form of diving, but I havn't given up my backplate/harness/wing and set of doubles, there are still many applications for them. Just thought i'd stir the pot and see what people thought on this... is the backplate/wing dying? Cave divers/tech divers like things simple and safe....how much more simple can you get than a solid steel backplate and a single piece of webbing with a wing... any thoughts?
For the most flexible/lowest profile rig the back plate has to go....but you can get 80-90% of the advantages of sidemount and still have your back plate. I know two proficient sidemount divers that still use their backplate. Neither has called a dive with me and my Transpack derived rig because they couldn't follow me.
Lee

[IowaCaveDiver]

I would agree that for sidemount, a backplate is not ideal, but I guess i was under the impression that people thought the plate should be gone or replaced even for application of diving a set of doubles.... i don't see any other way to really dive doubles, at least not anything better. I'd say for sidemount you'd want to shy away from a backplate because you wouldn't have the flexibility you might need to get get through some of the tight squeezes.... i'm just thinking outloud, i probably don't make much sense, just bored i guess.

[skip]

the backmount will never die. too many good applications for it. with back mount (does back mount require a backplate?) you can still carry two sidemount cylinders. i question the manifold. the manifold has two more points of potential failure than independent doubles back-mounted. i've heard sidemount divers claim this as a good reason for side mount: it provides independent double redundancy. but then you don't have access to all the air in both cylinders... confusing. so is the manifold on the way out? there is a trade-off (duh). i get a bit confused trying to "see" how independent doubles (sidemount) and manifold back mount and more than two cylinders all conspire to create the safety/risk ratio. toss in different divers with different configurations and cylinder sizes and it all just goes to mush for me. but then, i'm new to cave diving.... maybe those with more experience have clearer understanding?

but i do know a place where backmounted tanks won't let you in.... you can take them off and leave them (not the best idea), push them ahead, or go sidemount. jeeesh, maybe it's best to tailor your gear to the dive?
I heard once that DIR was prohibitive and that DW2 (Do What Works) was the way to go.

[JDR]

Would you mind posting a picture of your rig?
It would be interesting to see what you are doing.

[IowaCaveDiver]

I'd agree with all that you've said.... especially about the possiblity of the isolation bar heading out.... why not use independant doubles? I suppose the reason we still have the isolation bar is that if you loose one regulator you would loose that whole tank without it.... at least with the isolation manifold you can "isolate" the problem and most times still have access to the remainder of your air supply. I my opinion, i think doubles with the manifold will be around, but we'll see a lot more divers going to sidemount because of the versatility and increased safety factors... at least if you loose a regulator on sidemount you can still save the air. I'm going to start diving an H-valve on my left side bottle for redundancy and an extra level of safety for solo stuff. It will be very interesting where cave training goes in the next ten years.... as the popularity increases and more cave divers are trained, I wonder if any training agencies would go to a sidemount configuration. Is it possible to get cave certified without learning to backmount? Seems like it couldn't hurt.... anyway, back to the daily grind.

[Rich]

I'd agree with all that you've said.... especially about the possiblity of the isolation bar heading out.... why not use independant doubles? I suppose the reason we still have the isolation bar is that if you loose one regulator you would loose that whole tank without it.... at least with the isolation manifold you can "isolate" the problem and most times still have access to the remainder of your air supply. I my opinion, i think doubles with the manifold will be around, but we'll see a lot more divers going to sidemount because of the versatility and increased safety factors... at least if you loose a regulator on sidemount you can still save the air. I'm going to start diving an H-valve on my left side bottle for redundancy and an extra level of safety for solo stuff. It will be very interesting where cave training goes in the next ten years.... as the popularity increases and more cave divers are trained, I wonder if any training agencies would go to a sidemount configuration. Is it possible to get cave certified without learning to backmount? Seems like it couldn't hurt.... anyway, back to the daily grind.

Lately, I've seen a growing trend of people diving doubles with just a crossbar (no isolator).....

BTW check your PM about the tank fills :D

Safe diving,

Rich

[Deep-Thief]

Back mounts are here to stay for non restrictive dives. Why wouldn't you want an isolator? Independents are fine but you have to keep up with which reg you have in your mouth and your pressure alot more than with manifolds. Yeh Yeh on the two extra points of failure. You already have 10-15 whats the point? What safety factors do you gain by going to independents? Seems that all you gain is task loading on yourself. Just thought I'd throw out something to chew on.

[NitroxWarrior]

I've seen serveral cave entraces that are too small and round for side mounting to fit between. The old setup is not yet obsolete in my eye

[skip]

I don't have a picture handy, but guess now that you asked i'll get one. But my rig is traditional back mount. I do also have independent doubles for backmount. Same regs, but I add a pressure gauge to the left tank that is not present with the manifold doubles. I also dive with a sidemount sump diver in tennessee and being new to cave diving have worried about how much gas he will have for me should I have a catastrophic manifold failure. Back mounted independent doubles and side mount independent doubles are the same in terms of available gas supply, absence of manifold, and task loading (switching regs). By the way, the indie doubles are old and were my way of diving doubles without the expense of dedicated doubles and manifold.

I see that if sidemount diver keeps 2/3's for return he could hand off one tank to poor gasless me and we both could exit safely. right? but then what if one of his tanks fail and my manifold blows? so now we have only half of what is needed for both to exit...right? I guess this could go on ad infinitum....

[Webmaster]

I like sidemount so far primarily because of three things:

1) No single point of failure to lose ALL your gas from.

2) Personally I find it more comfortable (in the water). The weight of the tanks is arranged evenly around my center of gravity.

3) Having to carry tanks through a cave, or anything much other than an easy flat walk makes it a bit easier toting them one at a time. For a lot of places with easy access it's a bit more hassle gearing up because it's not all in one big chunk.

How is it really that different than back mounted independent tanks? They're just in a different place on your body.

I have enough trouble getting through some things without a backplate, but as long as you don't do anything tight it doesn't seem it would cause too much of a problem.

[normblitch]

It will be very interesting where cave training goes in the next ten years.... as the popularity increases and more cave divers are trained, I wonder if any training agencies would go to a sidemount configuration. Is it possible to get cave certified without learning to backmount? Seems like it couldn't hurt.... anyway, back to the daily grind.

As a former Caver ('80's) now re-certing, and NOT looking forward to the weight of back-mount dubs, I am wondering the same thing...

However, the logic may prevail, to wit, that SM is inherently more complex, and therefore an add-on or advanced cert...the Basics would (unfortunately) still be taught back-mount first, just as in Primary flight training one first trains/flys a simple-single, with variable-pitch coming only after first getting the private ticket ...

Norm

[curtschu]

I have a question, since there has been a lot of discussion about points of failure and such. How many folks have actually experienced a major failure while diving? I am talking about a Total Gas release, Complete Regulator shutdown Etc. I started diving in the early 90s and have several hundred dives and never have had a failure. This is not to say I haven't found a hose about to go and fixed it first. I have heard stories of guys running a manifold into the roof on a scooter, to to tell the truth I never met them. Also I talked about this with Kate in Mexico and she can't remember it ever happening either. I just wonder, not that I think we should ever become complacent.

[FW]

I have a question, since there has been a lot of discussion about points of failure and such. How many folks have actually experienced a major failure while diving? I am talking about a Total Gas release, Complete Regulator shutdown Etc.

Well gear has gotten a little better, but...

One of my buddies hit his reg going into the Ear, and broke off the regulator hose right at the 1st stage. Because of the current, he didn't notice until he was inside. By then he had had lost several hundred psi.

I was going into a sump in a single (something I wouldn't consider now). The tank O-ring blew, dumping all my gas. I was only a few feet in when it went, but the gas was all gone by the time I backed out.

I have seen several burst disk failures, including a couple of my own. Luckily, none in the water, but....

Moral, I prefer sidemount.

As for independants, they are ok, unless you loose a regualtor. Then you loose that whole tank. In sidemount, you *could* switch regs on the tanks. It would be nice to buddy breathe during the process, though :)

[Deep-Thief]

As for independants, they are ok, unless you loose a regualtor. Then you loose that whole tank. In sidemount, you *could* switch regs on the tanks. It would be nice to buddy breathe during the process, though :)

If you can do that in side mounts you "could" do it in BM. You can take your gear off underwater can't you? As for the extra points of failure, Its a mute point since I only need one pressure guage with my manifold and independents have to add another. Add the points of failure back in. As for things getting knocked off thats what they make first stage guards for. This is especially needed when scootering.

[FW]

If you can do that in side mounts you "could" do it in BM. You can take your gear off underwater can't you?

It is just a little hard, since you depend on the weight of the tanks to hold your exposure suit down :-)

[Angie Reim]

As for independants, they are ok, unless you loose a regualtor. Then you loose that whole tank. In sidemount, you *could* switch regs on the tanks. It would be nice to buddy breathe during the process, though :)

I dive sidemount. About a month ago I lost the o-ring between the 2nd stage and hose during an exit from Telford. Uncontrollable free-flow so I had to shut down the tank. Given that I keep my tanks within 200-300 psi of each other before switch, I had plenty of gas left in remaining tank to pull the lines and make the exit. Imagine, however, that no matter how close the exit all the possible scenarios for saving yourself pass through your mind including switching regs on tanks to access remaining gas. I might 'see stars' before finishing the job but I could envision doing it -- while still heading for the exit. Given the situation at the time I was barely stressed about what happened and mostly annoyed. BTW I did have a buddy for a backup but he would of been my last resort if we were further back. I'd rather not HAVE to 'see stars'. :lol:


If you can do that in side mounts you "could" do it in BM. You can take your gear off underwater can't you? I suppose you could, but try it sometime. It's probably near impossible and I can't see how you would do it without abandoning exit during the switch. Anything is worth a try though when you consider the alternative. :wink:



As for the extra points of failure, Its a mute point since I only need one pressure guage with my manifold and independents have to add another. Add the points of failure back in. As for things getting knocked off thats what they make first stage guards for. This is especially needed when scootering. True enough but those failure points in sidemount are easily accessible, visible and can be overcome. If you have two or more failures on the same dive -- well you're probably screwed but then so would you be in backmount.

I'm at the point now in SM that I can understand where BM is preferred at some sites due to the shape of a restriction, etc. but then if SM in that tunnel is a problem then so too might be airshare. I would still want independent tanks. Even so, in SM you can swim sideways for a distance (which I've done easily) or swim with one tank on and one tank ahead of you. Something I'm going to start practicing soon. The only problem I'm seeing with SM right now is a clutter issue on the rig but I'm working it and a lot of it is the 'operator'. :roll:

Don't get me wrong. BM is good stuff and preferable in the right environment. I'm just far more comfortable and a much better diver/buddy in sidemount. For me it's worth the one extra trip to the water. At the easy access sites my handtruck eliminates the extra trip altogether. :lol:

[Jordan]

Put an H-valve on one of your tanks with a spare reg. You can then save seeing stars until after the dive when you dip into your beer cooler.

[Moonfuzzy]

I see that if sidemount diver keeps 2/3's for return he could hand off one tank to poor gasless me and we both could exit safely. right? but then what if one of his tanks fail and my manifold blows? so now we have only half of what is needed for both to exit...right? I guess this could go on ad infinitum....

Ok, so what would happen in this situation if you were BOTH in backmount? You have lost all of your gas, and now one of your buddy's tanks fail... does he isolate (leaving one working reg), did his manifold blow, does it drain his tanks also, is it a bad reg, etc. etc.

Who will survive this really depends on what causes the problem and what your options are to fix it in water, but it seems to me that having independant air sources would be better for both of you in this situation.

[Angie Reim]

Put an H-valve on one of your tanks with a spare reg. You can then save seeing stars until after the dive when you dip into your beer cooler.

Hmm......neither is a bad idea. :lol:

It's a shame I sold that H-valve. ....

[Deep-Thief]

Ok, so what would happen in this situation if you were BOTH in backmount? You have lost all of your gas, and now one of your buddy's tanks fail... does he isolate (leaving one working reg), did his manifold blow, does it drain his tanks also, is it a bad reg, etc. etc.

Who will survive this really depends on what causes the problem and what your options are to fix it in water, but it seems to me that having independant air sources would be better for both of you in this situation.

First we are stretching this a little far, but for the sake of arguement, here goes. The first diver should not lose ALL of his air. Isolate. Then, there is only one point in a manifold where you could lose All of your air and isolating would not help. The chance of that one point failing is slim to none and slim just left the building. If both fail at that ONE point and you have no other gas then I guess Murphy (karma, God-whatever you call it) just wasn't on your side and its your time to die. BTW what happened to three to a team. Might not help if two lost all their air but then again what are the chances of that.

H valve on your rigs? How many more points of failure can we add? I am not knocking side mounts or independents. There is a time and a place for everything. I just think that when looking at the pros and cons of the three, what little extra safety you gain is negligible and offset with the task loading of switching regs/tanks. If you need the size due to restrictions then by all means. If its for medical reasons great. If its due to the worry about the manifold failing in that ONE location then I think you need to worry about JAWS and the blind cave monster eating you. :-D

[IowaCaveDiver]

I can't say i've ever had any type of major malfunction of any sort, although I am meticulous about my gear, I service it myself annually, sometimes more often, and take preventative measures to make sure no failure would be due to poor care. I havn't had anything knocked off or broken due to impact, but i don't yet scooter in caves....soon to come....but I guess this is why i've fallen in love with sidemount. I've only got half a dozen side mount dives under my belt, but when i start to scooter, that is how I will be diving. As for switching regs out, i wouldn't want to try it with a backmount setup.....to much risk of silt out and such, it would be much easier to switch out regs in sidemount, especially if you use an H-valve on one side with a spare first stage and reg.
I've heard of other people having faliures, but the most sever I heard of was my instructor rammed his manfold to the ceiling and broke off the head of the burst disk..... lost most of his air before it was isolated proceded to exit with his team and they had lost the line due to a siltout, but his training got him out.... anyway, we can't prevent everything, and i'm not a fan of manifold protectors....just more crap that stuff can get caught up on, so I guess we just have to be caught up on the training and keep our skills sharp.
-Matt

[WJH]

. . . The first diver should not lose ALL of his air. Isolate. Then, there is only one point in a manifold where you could lose All of your air and isolating would not help. The chance of that one point failing is slim to none and slim just left the building. . .

SLIM would never leave the building on you in the event of a gas failure. And if 2 of a 3-man team had total gas failures, SLIM would donate one reg to each and breathe through his gills on the way to the exit.

LOL

WJH

[Angie Reim]

. . . The first diver should not lose ALL of his air. Isolate. Then, there is only one point in a manifold where you could lose All of your air and isolating would not help. The chance of that one point failing is slim to none and slim just left the building. . .

SLIM would never leave the building on you in the event of a gas failure. And if 2 of a 3-man team had total gas failures, SLIM would donate one reg to each and breathe through his gills on the way to the exit.

LOL

WJH

Hahahahahahahhahaha! 'bout time someone put this thread to rest! :lol:

[Deep-Thief]

. . . The first diver should not lose ALL of his air. Isolate. Then, there is only one point in a manifold where you could lose All of your air and isolating would not help. The chance of that one point failing is slim to none and slim just left the building. . .

SLIM would never leave the building on you in the event of a gas failure. And if 2 of a 3-man team had total gas failures, SLIM would donate one reg to each and breathe through his gills on the way to the exit.

LOL

WJH

I want Slim on my team. He sounds like an upstanding kind of guy. I just want to know if he can share his gills with me so when all three have failures I can still get out. :lol:

[divindoubles]

just a thought, (probably a dumb one):

since the purpose of a manifold is (primarily) to give the diver access to the gas in both tanks without having to switch regs in an emergency, and obviously this would be a great advantage in a pucker or poop situation, wouldn't a modified high pressure hose between a set of SMs do the same thing? The flow would be small enough that if you needed to you could always just shut down the valve (assuming you use two h-valves) before losing much gas, but the advantage would be not having the extra task loading from switching regs and monitoring two separate SPGs. I'm sure this has been thought of or maybe even tried, but it just popped in my head (pronounced hayid) as I was reading this string.

DD

P.S. Please keep the flaming to a minimum----;o)

[Moonfuzzy]

just a thought, (probably a dumb one):

since the purpose of a manifold is (primarily) to give the diver access to the gas in both tanks without having to switch regs in an emergency, and obviously this would be a great advantage in a pucker or poop situation, wouldn't a modified high pressure hose between a set of SMs do the same thing? The flow would be small enough that if you needed to you could always just shut down the valve (assuming you use two h-valves) before losing much gas, but the advantage would be not having the extra task loading from switching regs and monitoring two separate SPGs. I'm sure this has been thought of or maybe even tried, but it just popped in my head (pronounced hayid) as I was reading this string.

Part of the benefit to diving sidemount config is having an isloated air source when diving solo... no one should dive solo without one, and in many sidemount tunnels you are solo - wether or not you are there with someone. Adding a hose between the tanks would add a failure point where the hose attached to each tank, and unless it is FULLY isolable then it is a hazard.

[WJH]

I want Slim on my team. He sounds like an upstanding kind of guy. I just want to know if he can share his gills with me so when all three have failures I can still get out. :lol:

He is definitely an upstanding kind of guy. Sharing gills would be way too kinky, though.

WJH

[BillGraham]

Here's my non-technical take: I've been sidemount diving for about a year and a half and I've used backmount gear exactly once in that time. Even then I was wishing I had the sidemount rig. I love it in caves, love it on wrecks, I even love it in the cold (after some practice with mitts).

I have had situations where backmount would fit better for trying to do something on a shipwreck--you do have a wide profile in sidemount. I've only been cave diving a short while but I'm much more comfortable in the sidemount rig, particularly where there's some flow.

Failures: I think the "both my buddy and I have a total catostrophic gas failure" scenario is something I can't really plan for. That holds true for me whether I'm in sidemount or backmount.

I once jumped off a boat with my isolation valve cranked down tight, wearing cold water gear, heavy underwear, mitts, and I can tell you that I can't count on my ability to turn that knob under all circumstances. Wearing sidemount, the valves are right by my hands. After reading all this good analysis I'm thinking of using a long hose on one tank, inner-tubed down , hmm.

The clutter factor in sidemount is something to overcome. I was taught to clip off my reels on the same loops you clip your tanks to. Backup lights can go high on the shoulder straps, I made some surgical tube loops with big beads to hold the regs, hoses crossed over.

[DeWayne]

just a thought, (probably a dumb one):

since the purpose of a manifold is (primarily) to give the diver access to the gas in both tanks without having to switch regs in an emergency, and obviously this would be a great advantage in a pucker or poop situation, wouldn't a modified high pressure hose between a set of SMs do the same thing? The flow would be small enough that if you needed to you could always just shut down the valve (assuming you use two h-valves) before losing much gas, but the advantage would be not having the extra task loading from switching regs and monitoring two separate SPGs. I'm sure this has been thought of or maybe even tried, but it just popped in my head (pronounced hayid) as I was reading this string.

DD

P.S. Please keep the flaming to a minimum----;o)

I still don't get it, what is so difficult about looking at 2 spg's and switching regs? Dive often enough and pay attention to what you are doing and you should just about be able to predict how much gas you have before you even look at your guage. This is a good trait to develop as it can alert you to small issues before they grow into major problems.

[BillGraham]

I agree with Dwayne, the switching regs part is easy. Breath one tank down a third, breath the other down a third and turn the dive. I know some people who like to switch more often to keep the pressures closer, but that's personal preference.

Does anyone use a long hose on their sidemount rig? Just curious . . .