JimC
March 30th, 2007, 02:37 PM
There are a number of things that sidemount can provide a diver. I will get to those later. But why do most people get into sidemount in the first place? The answer is simple. Sidemount gets you places backmount cannot. In an overhead environment there are big places and small places. Sidemount gets you into the small places and after a time on backmount you start wondering whats down that tunnel you don't fit in. After a while longer you realize you don't fit in over 1/2 the tunnels in the cave, or just cannot get into some area in some wreck.
This is where alternate configurations start to come in. Sidemount, and even more so sump and nomount systems get you into smaller and smaller places. With that size comes a corresponding increase of skill needed and a decrease of the ability to receive help from a team member. So, on to the good and the bad, as I see it. After sidemounting for a while I came to realize that the ability to 'go small' was only a small point of the overall configuration and that there were many advantages to the system that could carry into all the diving I was doing. So much so, that I would rank most of these advantages over the ability to 'go small' in the whole question of why sidemount.
In short, the good - in order of importance to me:
- Ability to fully manipulate valves and regulators. With the position of your primary gas it is a trivial task to manipulate the valves and regulators. So much so to the point that you can with little practice swap regulators from one tank to the next on a short breath hold in dire circumstances.
- Completely independent tanks. There is no single failure that can eliminate more than about 1/2 your remaining gas supply. This means no single failure can remove the ability to extricate your self from the dive if you follow reasonable gas management. Manifolded doubles have some rare situations where this is not true and reliance on an external gas supply would be mandatory.
- That combined with point #1 means that short of a few very rare failure modes no single failure will remove access from all of you're gas. Between feathering valves and swapping regulators there is a way to access that gas.
- Clean back. With no tanks on the back you can get up closer to the ceiling and hide from the flow without damaging the environment. This has a lot of great advantages in and of it self but the primary one here is that you have no entanglement areas on your back where you cannot reach them. Instead, your entanglement areas move to your chest area where they are easy to deal with.
- It goes small! Woo. Between tank removal and what not you can fit into damnable small places.
- Dynamic balance. With the ballast distributed more on your centerline I find it much easier to assume non-horizontal, face down positions should I need to. Rotation, pitch and yaw control are to be marveled at in a properly balanced sidemount rig. To quote something I heard once "the trim control is criminal".
- Less to carry. With independent cylinders, you have the option to carry them one at a time for fills and to the water.
The Bad:
- It can be a hassle to gear up and get in and out of some boats and entry conditions. You need more room on ladders, benches and walking with tanks on can be difficult.
- Carrying multiple stages is more difficult than on a traditional backmount rig. The side bottles interfere fear with correct positioning of the stages and carrying more than one on each side is cumbersome. Use of leashes is recommended for more than two stages where you can comfortable carry 3 or 4 stages on backmount without having to resort to a leash.
- Exposed head. Without tanks above your head on your back, if you make contact with the roof, it is often with your head first. While a helmet can mitigate this risk your head is still more exposed to impact. On a scooter this impact could be dangerous even with a helmet.
This is where alternate configurations start to come in. Sidemount, and even more so sump and nomount systems get you into smaller and smaller places. With that size comes a corresponding increase of skill needed and a decrease of the ability to receive help from a team member. So, on to the good and the bad, as I see it. After sidemounting for a while I came to realize that the ability to 'go small' was only a small point of the overall configuration and that there were many advantages to the system that could carry into all the diving I was doing. So much so, that I would rank most of these advantages over the ability to 'go small' in the whole question of why sidemount.
In short, the good - in order of importance to me:
- Ability to fully manipulate valves and regulators. With the position of your primary gas it is a trivial task to manipulate the valves and regulators. So much so to the point that you can with little practice swap regulators from one tank to the next on a short breath hold in dire circumstances.
- Completely independent tanks. There is no single failure that can eliminate more than about 1/2 your remaining gas supply. This means no single failure can remove the ability to extricate your self from the dive if you follow reasonable gas management. Manifolded doubles have some rare situations where this is not true and reliance on an external gas supply would be mandatory.
- That combined with point #1 means that short of a few very rare failure modes no single failure will remove access from all of you're gas. Between feathering valves and swapping regulators there is a way to access that gas.
- Clean back. With no tanks on the back you can get up closer to the ceiling and hide from the flow without damaging the environment. This has a lot of great advantages in and of it self but the primary one here is that you have no entanglement areas on your back where you cannot reach them. Instead, your entanglement areas move to your chest area where they are easy to deal with.
- It goes small! Woo. Between tank removal and what not you can fit into damnable small places.
- Dynamic balance. With the ballast distributed more on your centerline I find it much easier to assume non-horizontal, face down positions should I need to. Rotation, pitch and yaw control are to be marveled at in a properly balanced sidemount rig. To quote something I heard once "the trim control is criminal".
- Less to carry. With independent cylinders, you have the option to carry them one at a time for fills and to the water.
The Bad:
- It can be a hassle to gear up and get in and out of some boats and entry conditions. You need more room on ladders, benches and walking with tanks on can be difficult.
- Carrying multiple stages is more difficult than on a traditional backmount rig. The side bottles interfere fear with correct positioning of the stages and carrying more than one on each side is cumbersome. Use of leashes is recommended for more than two stages where you can comfortable carry 3 or 4 stages on backmount without having to resort to a leash.
- Exposed head. Without tanks above your head on your back, if you make contact with the roof, it is often with your head first. While a helmet can mitigate this risk your head is still more exposed to impact. On a scooter this impact could be dangerous even with a helmet.