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AD_ward9 · 2nd January 2008, 14:10

Your point on wet suits is a good one. I use either a dry suit or just my shorts. My wet suits have not been used in years: mine weight a lot and take too much baggage space so when going somewhere with warm water packing a thin fibrepile is enough to stop the rebreather bolts and clips from wearing a hole in my back.

There are two situations where one needs to dump buoyancy during the dive: gas emptying from tanks and wet suits. These issues mean that a BCD, perhaps with just an injector, will have to stay on RBs when they leave the factory, and the BCD-less unit just a personal unit.

So we are definitely then restricting this to personal use. A 0.6l tank feeding a single wing would have the same effect as what I am proposing: it is just I prefer the dual bladder. Using a cheap flow orifice means one only needs the cylinder and the tank valve (no reg).

Thanks for your suggestions and thoughts about this,

Alex

Quote: (Originally Posted by Tino de Rijk)

Personally I don't see a lot of advantage.
It would only work in tropical situations, i.e. with only a thin shorty.
Even with a normal sort of wetsuit (even if only a 5 mm overall; I dive all summer with a wetsuit; I hate drysuits, think they are a necesary evil on cold waters) you easily loose 1-2 kilo's of weight due to suit compression on depth - even as shallow as 20 meters or so.

Also, you need to cater for buoyancy increase in case of e.g. OC bailout. Even if you only use an inboard 3 liter dil as bailout, and empty it during an OC ascent, this represents 600 liters, or almost a kilo in weight. If you also use your O@ cylinders: 1200 liters, or almost 1.5 kilo. The last thing you want in an emergency is to fight negative buoancy in the shallows, as there is no good/comfortable way to do that.
If there is one thing I hate more than being too heavy, it is being too light at the end of my dive: you're tired, on the ascent line, having to swim with your fins up, wasting lots of energy (and gas!) and the risk of making an uncontrolled ascent in the most dangerous pressure range (0-10 meters).

I use a 1 liter steel 200 bar cylinder on top of my inspo, replacing the topweight. This "fuels" either my drysuit or my wing (when diving wetsuit). Depending on the dive, I remove it, and just use the inboard dil to fuel my wing (on easy wetsuit dives).
In both cases the (normal length) LP hose goes under the arm and under the (left) CL, so no clutter there as well. Should be standard IMHO anyway, as an over-the-CL hose is asking for problems for various reasons.

As to clutter reduction: my config is not more cluttered to carry around than 2 small cylinders: it is either 1 x 1 liter behind my head (with a very small low-flow 1st stage on it) versus "your" 2 x 0,3 liter, or even just a single extra LP hose versus "your" 2 x 0.3 liter.

I agree with you that being too heavy is very likely a major accident reason for Rebreather (AND OC!) divers, and divers (and instructors!) should pay more attention to it, but forcing it on them by limiting their options is IMHO not a good approach.

Ciao,

Tino.

2nd January 2008, 14:10	#34 (permalink)
AD_ward9 So much more to learn Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jun 2005 Location: Scotland Posts: 1,726	Re: Getting rid of the last bits of junk ... Your point on wet suits is a good one. I use either a dry suit or just my shorts. My wet suits have not been used in years: mine weight a lot and take too much baggage space so when going somewhere with warm water packing a thin fibrepile is enough to stop the rebreather bolts and clips from wearing a hole in my back. There are two situations where one needs to dump buoyancy during the dive: gas emptying from tanks and wet suits. These issues mean that a BCD, perhaps with just an injector, will have to stay on RBs when they leave the factory, and the BCD-less unit just a personal unit. So we are definitely then restricting this to personal use. A 0.6l tank feeding a single wing would have the same effect as what I am proposing: it is just I prefer the dual bladder. Using a cheap flow orifice means one only needs the cylinder and the tank valve (no reg). Thanks for your suggestions and thoughts about this, Alex Quote: (Originally Posted by Tino de Rijk) Personally I don't see a lot of advantage. It would only work in tropical situations, i.e. with only a thin shorty. Even with a normal sort of wetsuit (even if only a 5 mm overall; I dive all summer with a wetsuit; I hate drysuits, think they are a necesary evil on cold waters) you easily loose 1-2 kilo's of weight due to suit compression on depth - even as shallow as 20 meters or so. Also, you need to cater for buoyancy increase in case of e.g. OC bailout. Even if you only use an inboard 3 liter dil as bailout, and empty it during an OC ascent, this represents 600 liters, or almost a kilo in weight. If you also use your O@ cylinders: 1200 liters, or almost 1.5 kilo. The last thing you want in an emergency is to fight negative buoancy in the shallows, as there is no good/comfortable way to do that. If there is one thing I hate more than being too heavy, it is being too light at the end of my dive: you're tired, on the ascent line, having to swim with your fins up, wasting lots of energy (and gas!) and the risk of making an uncontrolled ascent in the most dangerous pressure range (0-10 meters). I use a 1 liter steel 200 bar cylinder on top of my inspo, replacing the topweight. This "fuels" either my drysuit or my wing (when diving wetsuit). Depending on the dive, I remove it, and just use the inboard dil to fuel my wing (on easy wetsuit dives). In both cases the (normal length) LP hose goes under the arm and under the (left) CL, so no clutter there as well. Should be standard IMHO anyway, as an over-the-CL hose is asking for problems for various reasons. As to clutter reduction: my config is not more cluttered to carry around than 2 small cylinders: it is either 1 x 1 liter behind my head (with a very small low-flow 1st stage on it) versus "your" 2 x 0,3 liter, or even just a single extra LP hose versus "your" 2 x 0.3 liter. I agree with you that being too heavy is very likely a major accident reason for Rebreather (AND OC!) divers, and divers (and instructors!) should pay more attention to it, but forcing it on them by limiting their options is IMHO not a good approach. Ciao, Tino.
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