Getting rid of the last bits of junk ...

AD_ward9

The scallop bag is dragged along the bottom anyway, until it goes up on the SMB. Carrying scallop bags up attached to your person is a pain, especially big ones: even hanging below they get tangled up in the line. This is all about streamlining.

The unconscious diver should be neutral (mouthpieces should have retainers, as EN14143 describes, so the Rebreather does not flood). In a flood, one can put in a squeak of gas (which is why I suggested 300ml cylinders rather than 50ml, as that is all that is really needed if it is just a one shot per side).

The brass goes to the lift bag. It is a hazard bringing up lumps of metal. They get in the way, need attention, and when they fall off your kit, they can cause quite a surprise.

Which leaves the problem of the cylinders getting lighter as the dive progresses, especially big bail out cylinders.

Thanks Teoman, but the idea is not to send your rebreather up on its own. Just imagine how well that would down .... he jumped in the water, then the next thing was saw was his rebreather floating around ... we rescued that but he wasn't attached, but you'd never guess what, the beggar was still alive on his bail out and he had a transponder with him. The lifeboat crew and police gave us a real hard time. Last time I'm having a rebreather nut on my boat .... Just in principle anyway, getting rid of the rebreather is too risky underwater.

Mverick's thought on hoses under the arms is quite interesting. Some RBs do that. The MSA HAZMAT rebreathers as an example. We did some experiments four or five years ago using a drilled out Autoair. Will think about that some more, as it is good to keep the shoulders free.

Alex

fireman

How about a "diver ballast tank". Say a ft3 you could fill with water or blow out as necessary and it wouldn't change buoyancy with depth...

__________________
Heres to you Capt. Bill
Never Forget, and stay safe everyone.

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.

AD_ward9

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

Tino de Rijk

"Warm water" is a relative thing...... "warm" in holland (or even France or Spain) is around 20 C, good enough for a thin wetsuit, not good enough for a fibrepile. That in my book is "hot" diving :-)).

I can understand your favor for a double wing, but that also IMHO is depending on dive profile. When I dive wet, and my trim is good, a BCD failure can be easily compensated by either running the CL's a bit bigger (assuming that, as part of your proposed better educated diver in terms of buoyancy, he also adheres to the minimum loop volume mantra - if only to avoid backaches, like in my case....) or dropping part of his weight (easier these days with integratred weight pockets). Although I hate them for big weights (as necesary with some drysuits), they can fit a nice role as "droppable" part of an overall weight system: main part on your good old belt, droppable part on the dispensable pouches. You may want to consider such (limited capacity) pouches in your design.
So no need for the double wing in my view in many cases.
As a reference: a standard prescribed IANTD drill is showing that you can hover and ascent with a failing BCD/wing. An SMB also does the trick.
But again, Alex: personal preference. To me a double wing is clutter as well on the average not-so-deep dive.

ciao,

Tino.

AD_ward9

It is a scar. A dive about 7 years ago, when a wing injector got stuck on a trimix dive, and my buddy found he needed to use the a pointed dive knife for the first time in his four thousand dives. Using an SMB inside a wreck as a substitute, is not really an option, and crawling along a sideways floor or ceiling would silt out.

With a tiny cylinder on each side, a redundant wing becomes the logical format.

Anyhow, as you say, it is down to preferences: you use a 1ltr overhead cylinder, and I am using now two tiny cylinders with no regulator on them for the same purpose. Two variants of the same thing.

Alex

Tino de Rijk

Yep. Most important is you should dive what makes you feel happy / comfortable, a.o. based on past experiences! That's why I don't like DIR: too little room to fit in your own preferences; too much "one size fits all".....

Ciao,

Tino.