Embedded Files
There are moments when I think of bottle diving as a sort of technical bog snorkelling. I believe that a normal solo diver configuration can be used as a starting point. The key features are therefore a completely independent reserve system such as a 3 litre pony bottle and regulator, and various selected cutting tools. This arrangement is also at the core of a P.S.D. system.
So far so good. But now, for a real technical challenge, let's consider the following working assumption:
"Any area that has been used for dumping must be assumed to be polluted unless there is sufficient evidence to the contrary."
What the above assumption means for the recreational bottle diver is this. Even if the water seems to be OK from up close, the very fact that it has been used for dumping indicates that it is potentially compromised and may therefore harbour noxious chemicals or disease bearing organisms. The appropriate hazmat (hazardous materials) gear must therefore be worn in order to mitigate those risks.
Admittedly it does make you look like some sort of amphibious mutant ninja womble, and in a minority of situations such equipment can be overkill. I have found bottle sites along lakeshores that really are as clean as a whistle, and which I elected to work in a 7mm wetsuit and ordinary half-mask. However, the majority of sites present at least some element of doubt - e.g. no fish, limited volume, deoxygenation, limited ingress/egress (flushing) of water, possible agrochemical dumping implied by proximity to farms, possible dumping of industrial waste implied by proximity to urban areas, etc. - and that is when the above assumption becomes a sensible one to make.
Here is a breakdown of the typical (“bog standard”) equipment manifest that I use when working a site:
1) Full Face Mask (F.F.M.). This type of mask covers the entire face and can provide a reasonable seal with certain types of hood. For many years the hazmat market has been dominated by the AGA mask, though I prefer the newer Poseidon Atmosphere which I find to be somewhat more user friendly. There is a switch on the second stage which allows a selection to be made between ambient and positive pressure modes. In ambient mode, the internal pressure matches the external, whereas positive mode raises the internal pressure to a slightly higher level. I used to own a Scubapro bugmask that was ambient mode only, and it required occasional purging to clear the mask of seepage. If a diver has positive pressure inside the mask then any break in the seal is more likely to result in air flowing out than fouled water leaking in, and it is nice to have this option with the Poseidon. The disadvantage of positive pressure is that the mask pushes outwards against the straps, and any movement of the head increases the likelihood of a warp in the seal and of at least some air burping round the edges. In practice I find the seal of the Poseidon to be excellent and I usually just keep the mask set to ambient pressure.
2) Trilaminate front entry drysuit. I prefer trilaminate since it is easier to decontaminate than neoprene. The only neoprene I have is in the outer gloves where the thickness provides more reassurance when handling broken glass. The drysuit zip has to be front entry to allow self-donning. I use an Otter Britannic drysuit with reinforced knee patches and fixed thigh pockets, and a Northern Diver undersuit.
3) Latex dry hood. The bottom of the hood rolls over the drysuit neck seal. The F.F.M. goes over the hood and seals against it around the face. This should be done carefully since a latex hood has sufficient elasticity to be stretched by the buoyancy of the mask, which puts strain on the jaw and facial muscles, along with the unnerving sensation that the mask wants to pop off unless it is kept face down. The solution is to make sure that the hood is kept under the chin, so the mask has no opportunity to drag at it. Neoprene wet hoods are another option, but they expose the head to contaminants, so their use is something of a judgment call. Some public safety divers use neoprene wet hoods as a matter of course and cut exhaust vents in them to allow any gas blown from under the F.F.M. seal to escape. I have used wet hoods occasionally, though I have found it unnecessary to cut slits as long as I seal the mask against my face rather than the hood itself. However, don't be tempted to pull the hood over the straps of the mask, since this would reduce your ability to remove it quickly in an emergency. Remember, the mask straps should always be over the hood.
4) Environmentally sealed first stage for main tank.
5) Dry suit inflator.
6) Stab jacket inflator.
7) Stab jacket (Buoyancy Compensator Device, or B.C.D.). I make good use of the pockets, in which I keep a lift bag, reel, goody bag, and at least two torches. Reel on the right, lights and lift bag on the left. These items are clipped onto the B.C.D. adjustment strap D rings which are then fed through under the pocket flaps. This means that I can easily find my way into the pockets and find the items by feel, simply by hooking my thumbs under the the straps and following them down. I've recently upgraded from a recreational style BCD to a wing & backplate, but the arrangements are the same.
8) 12 litre steel tank, 232 bar.
9) Console, including depth gauge, pressure gauge, and compass. I don't generally use a dive computer for bottle diving since the operational depth tends to be no more than twenty feet or so. Incidentally, I prefer a gauge that is graded in feet rather than metres because of the comparative shallowness of bottle dives.
10) Environmentally sealed first stage for pony tank. This should lie between the first stage of the main tank and its shoulder, and so as not to impair the routing of hoses. Note: it should be possible to reach back behind the head with the right hand in order isolate either valve. Using the left hand to raise and tilt the main tank from the base can make this easier.
11) Pony bottle pressure gauge.
12) Pony bottle, steel, 3 litre, 232 bar. The bottle should be tucked in so it is flush with the stab jacket. The first stage of the pony should not interfere with hoses leaving the first stage of the 12 litre, and should not sit any lower than the shoulder of the main tank.
13) Pony bottle second stage, which is held in place just below the throat with a bungee cord necklace.
14) Outer gloves. I use Kevlar reinforced three finger neoprene mittens. I consider such reinforcement to be essential when working with broken glass...ordinary dive gloves get torn to shreds. I also have latex medical gloves inside the mittens which can be rolled over the drysuit cuffs.
15) Spare knife, preferably a small one with a flat handle so it can be tucked in a pocket or under a glove. I use a cheap sgian dhu with a plastic handle and sheath.
16) Dive shears, accessible with either hand. These are better than a knife at cutting line.16) B.C.D. knife, accessible with either hand.
17) Weight belt.
18) Thigh pockets. I keep a spare half-mask in one of them. If I ever need to ditch the F.F.M. and use the pony tank then there is a mask to use with it. The other pocket can be used for a slate and pencil or to hold the occasional intact find, which can be a bit easier than lugging round a goody bag.
19) Ankle weights.
20) Fins. I use Scubapro Jetfins. These uncompromising garden spades have been in production for years.
21) Watch. Some sort of waterproof trench watch is necessary for this kind of work. It must be shock resistant, and yet cheap enough to be a beater watch. I recommend analogue dials with clear numbers for underwater use in poor conditions. One cheap option is the Russian Vostok “Amphibia” type. These watches currently retail for about 35-40 quid new. A crystal protector is advisable for bottle diving – modern plastic ones are great, they can be UHU'd onto the glass and are less obtrusive than a shrapnel guard. G-Shock watches are generally good, but I have known certain models (e.g. DW-5600) to interfere with a compass. I currently use a G-Shock G1500B-5A which is solar powered and needs no maintenance, and it has proven to be excellent.
Three things are notable by their absence. I don't wear a knife on the calf - in my view this is a bad place for a knife since it is too likely to catch on something. For similar reasons I don't have a bulky dive computer or depth timer strapped to my wrist. Thirdly, I don't have any exposed fin straps or buckles to catch on anything. I used to tape them down, but now I have spring clips which are less of a carry-on.
One other thing to point out. The gauges are fed through the B.C.D. arms to improve streamlining and stop them from dragging in the silt. This is much neater than using clips.
Page updated
Google Sites
Report abuse