OP
Going tech, backmount or sidemount doubles?
- Thread starter markmantei
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JamesK
Contributor
I think most of us DO agree with that. I don't know of anyone that disagrees with that statement.
JamesK
Contributor
I think some just don't feel the perceived advantages out weigh the perceived disadvantages.
Adobo
Contributor
Everyone agrees that side mount has a place and there are definitely dives that can only be done in side mount.
However, the question here is, do the advantages that side mount diving provide over back mount out weigh the disadvantages for the beginning technical/cave diver.
From the original post:
For the beginning or even advanced technical diver (open water), I don't see what the advantages are.
For the beginning cave diver, you will go through intro to cave, do a bunch of dives, and go through full cave before any thought of side mount passages are really considered.
How much full cave level diving experience do you think one will have before they have exhausted the majority of cave diving that can be done on back mount?
Now, weigh those considerations against the disadvantages listed by the other posters. And again, the context of the discussion isn't for a seasoned cave diver. The context is for someone just getting into tech diving or someone who is just getting into cave (or even cavern) diving.
JamesK
Contributor
So you are saying that you agree that they both have their advantages.
DaleC
Contributor
My advice would be to dive all sorts of configurations until you understand that it doesn't really matter that much.
Some BM divers will see gas loss with independent doubles (which SM's are) in a negative way (you could lose half your gas) but I see it in a more positive light (you can only lose half your gas). With a modern manifold you can potentially lose all your gas (or more than you bargained for) if you don't isolate fast enough. As a solo diver I would rather accept the loss of half gas than all gas because I cannot depend on donation from a teammate and I don't like the notion that true redundancy is predicated on an action to be initiated while a failure is occurring. SM divers need to place the emphasis on gas management, BM divers need to place the emphasis on isolation drills. Six of one, half dozen of the other. A team diver, confident in their ability to isolate, may have a differing opinion but that's all it is - a differing opinion.
Having said that, I have done dives with manifolded doubles, independent doubles and large single/stage combos and they were all good learning experiences. If you want to be an advanced recreational or technical diver I would suggest that breadth of experience is just as important as depth.
Some BM divers will see gas loss with independent doubles (which SM's are) in a negative way (you could lose half your gas) but I see it in a more positive light (you can only lose half your gas). With a modern manifold you can potentially lose all your gas (or more than you bargained for) if you don't isolate fast enough. As a solo diver I would rather accept the loss of half gas than all gas because I cannot depend on donation from a teammate and I don't like the notion that true redundancy is predicated on an action to be initiated while a failure is occurring. SM divers need to place the emphasis on gas management, BM divers need to place the emphasis on isolation drills. Six of one, half dozen of the other. A team diver, confident in their ability to isolate, may have a differing opinion but that's all it is - a differing opinion.
Having said that, I have done dives with manifolded doubles, independent doubles and large single/stage combos and they were all good learning experiences. If you want to be an advanced recreational or technical diver I would suggest that breadth of experience is just as important as depth.
Where do you get that idea? I didn't say anything about free flowing regs. There are other failures that could require feathering a valve.
What options are you given across the most common failure modes? And what do you consider the most common failure modes?
markmantei:
I don't know who explained this to you but swapping regs underwater is not something you want to do, especially if you only have 2 cylinders. My guess is whoever told you this either doesn't know much about sidemount and has never done this.
jimmy71
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I just wanted to chime in to the OP. I went through this same debate and have a very very active sidemount community in my area that is not associated with cave diving. My tech instructor does all his tech dives in SM. His 300ft+ dives have him with 6 total tanks, 2 bottom gas and 4 deco tanks. He does not stage and carries the tanks until he is done with them. He is a believer of sidemount having worked on the design of OMS system. My area has about a 50/50 split of BD/SM in the tech arena. The do it for reasons other than penetrating areas where it is required. Much like what you are talking about. So I will share my experiences.
Gear considerations: I will mainly focus on your DP/W as this surprised me and I wish someone had shared this info with me. The way my BP/W is configured, I can switch between BM doubles, Single BM rec, and SM in approx five minutes. All of this is with the same BP/W/Harness. This has been a huge advantage/benifit with me. The other day I got on the boat and realized that My manifold had developed a leak at some point during packing and I could not dive my doubles. Insteed of loosing my dives, I quickly converted my gear to single tank setup and grabbed a few of the shops 80 to dive. Dive continues. Granted this was a rec trip. The gear differences between BM and SM is not as great as you may think. Now there are dedicated SM set ups that may shave a inch or two off your profile, but that does not seem a benefit to you for the cost at this point.
Another reason I had trained in sidemount was the hope of decreasing some costs while vacation Diving. Like has been said, Grab two al80s and you now have a lot more gas and redundancy to dive deeper/longer. This was my plan in Bonaire, but I quickly realized that without tanks full of O2 or high concentration EANx for deco, this was not really much of benefit.
As people have pointed out, what ever gear you decide to do your tech training in, you need to be pretty comfortable in it. BM doubles is not that far of a jump from a back mount single tank. The feel and buoyancy do not change as much as you may think. You are going to need a few dives in SM to get comfortable enough to be able to manage the extra tasks. Think of it much like a drysuit. Would you want to start your tech training in a drysuit if you did not have a decent number of dives in one? It would be a train wreck and I would be surprised to see an instructor doing it. I would also ask if your tech instructor does tech dives in SM. There are differences that need to be considered. Having a tech instructor who only dives BM would not be the best instructor to teach you how to tech dive SM.
Most of the people who are SM in my area are doing so to help mitigate flexibility issues as mentioned here. They also like the ability to shuttle gear to/in the water to help relieve weight on knees and backs. They mount tanks in the water, but that works with the type of diving we do, deep freshwater without waves. Most ocean boats will not be able to hand your tanks down so that you can clip off in the water. Just something to think about.
I have taken a lot of the lessons I learned in the sidemount class and still use them even though I decided to go/stick with BM. Like I said my gear and change between them. I really liked the way tanks are slung in SM. I still use the rigging to sling my deco tanks. I woudl say that other than the cost of the class, The only pieces of gear that are SM only (not used in BM) I bought that I do not use are two high pressure gauges on 2in hoses and a couple bungees. Not a big deal.
Jimmy
Gear considerations: I will mainly focus on your DP/W as this surprised me and I wish someone had shared this info with me. The way my BP/W is configured, I can switch between BM doubles, Single BM rec, and SM in approx five minutes. All of this is with the same BP/W/Harness. This has been a huge advantage/benifit with me. The other day I got on the boat and realized that My manifold had developed a leak at some point during packing and I could not dive my doubles. Insteed of loosing my dives, I quickly converted my gear to single tank setup and grabbed a few of the shops 80 to dive. Dive continues. Granted this was a rec trip. The gear differences between BM and SM is not as great as you may think. Now there are dedicated SM set ups that may shave a inch or two off your profile, but that does not seem a benefit to you for the cost at this point.
Another reason I had trained in sidemount was the hope of decreasing some costs while vacation Diving. Like has been said, Grab two al80s and you now have a lot more gas and redundancy to dive deeper/longer. This was my plan in Bonaire, but I quickly realized that without tanks full of O2 or high concentration EANx for deco, this was not really much of benefit.
As people have pointed out, what ever gear you decide to do your tech training in, you need to be pretty comfortable in it. BM doubles is not that far of a jump from a back mount single tank. The feel and buoyancy do not change as much as you may think. You are going to need a few dives in SM to get comfortable enough to be able to manage the extra tasks. Think of it much like a drysuit. Would you want to start your tech training in a drysuit if you did not have a decent number of dives in one? It would be a train wreck and I would be surprised to see an instructor doing it. I would also ask if your tech instructor does tech dives in SM. There are differences that need to be considered. Having a tech instructor who only dives BM would not be the best instructor to teach you how to tech dive SM.
Most of the people who are SM in my area are doing so to help mitigate flexibility issues as mentioned here. They also like the ability to shuttle gear to/in the water to help relieve weight on knees and backs. They mount tanks in the water, but that works with the type of diving we do, deep freshwater without waves. Most ocean boats will not be able to hand your tanks down so that you can clip off in the water. Just something to think about.
I have taken a lot of the lessons I learned in the sidemount class and still use them even though I decided to go/stick with BM. Like I said my gear and change between them. I really liked the way tanks are slung in SM. I still use the rigging to sling my deco tanks. I woudl say that other than the cost of the class, The only pieces of gear that are SM only (not used in BM) I bought that I do not use are two high pressure gauges on 2in hoses and a couple bungees. Not a big deal.
Jimmy
OP
markmantei
Contributor
Thank you all for your comments and suggestions. I did a pool session with a sidemount instructor and was able to try a few different rigs. The adjustment was probably easier than I thought it would be, although that doesn't mean there there will need to be significant time invested to become comfortable and proficient in sidemount gear. I have decided that I will do the tech course in sidemount, and have ordered a Nomad XT. I won't have alot of time to master sidemount before the pool sessions but will have ample time before OW dives as they will not be done until mid June.
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