From UKRS, written by the guy who also penned the Genesis Of DIR, we have... DIM divers!
The problem with most so-called "safe" diving practices in existence
today is that the equipment that gets the diver out of trouble is
frequently also the cause of him being in trouble in the first place.
DIM diving aims to eliminate this risk by removing as many things as
possible from the diver's rig, and thus cut down on the number of
things that can go wrong with it. A brief overview of a DIM diver's
equipment follows below.
We start with the air supply.
- A back-mounted single cylinder is used. It is obvious that using
more than one cylinder increases the number of valves and O-rings
which are capable of failing, and manifolded twinsets are even worse
in this respect. One valve with one regulator is far safer than two
regulators on two valves with another valve sitting in the middle - a
total nightmare from a failure point perspective.
Faber now manufacture single cylinders with over 20L water capacity,
and in the event of even more gas being needed, a regulator can be
adapted for use with J cylinders.
- On the single cylinder, we attach our (DIN, of course) first stage.
Apeks DS1 are recommended, since these have a very low number of
ports, and thus less O-rings to blow.
On the first stage, a single demand valve is attached, and nothing
else. The demand valve should be on a twelve-inch hose - any shorter
and you'll have difficulty turning your head, any longer and you just
have more hose to develop a problem.
True, sharing gas with another diver is more awkward with this
configuration, but by using such minimalist principles, the likelihood
of ever needing to is so low as to be unworthy of consideration.
- SPGs are a useless encumbrance. If you know your breathing rate and
you know your planned depth, you can work out exactly how much gas you
will need for any dive. Proper dive planning should, therefore, mean
you always have enough gas. An SPG simply encourages a lack of proper
- Direct feeds are not necessary - all inflation should be
accomplished orally. Ignore the whiners who argue that drysuits cannot
be orally inflated - your drysuit should be ordered with no valves or
valve holes. Then, simply punch a hole in the upper left arm where the
autodump would usually be fitted, and attach a BCD corrugated hose.
You now have a DIM drysuit, which can be inflated orally. By
eliminating the more usual dump valves, you ensure that air will only
be dumped from your suit when you want it to, and without any risk of
clogging from your undersuit.
In addition, the warm exhaled air that inflates the suit removes the
need for argon, and the corrugated hose allows the DIM diver to
breathe the air in the suit on ascent in the highly unlikely event of
an OOA situation.
- The DIM diver does all buoyancy control on his drysuit, via the
corrugated hose. BCDs are not worn - a well-maintained drysuit should
never suffer enough of a leak that it cannot provide buoyancy.
In the event, however, of the drysuit being incapable of providing
enough lift, a lift bag should be used. Once again, inflation is oral,
via gas exhaled from the DV.
- An open-ended lift bag should be used. The self-sealing types rely
on complex designs and over-pressure valves, and once again are
therefore more likely to fail. A simple bag has much less to go wrong
with it. By only deploying in a situation where positive buoyancy
cannot be established, the diver guarantees that they will keep a
weight on the line that prevents the gas from spilling out.
Unless the lift bag is needed for alerting the surface as well as a
source of buoyancy, the diver should hold onto the bag throughout the
ascent. Like a reverse parachute, the DIM diver will simply hang
underneath the bag and allow it to pull him up. Excess air due to
pressure decrease is vented simply by squeezing the bag.
However, if the lift bag simply must reach the surface prior to the
diver, then it may be put onto a line.
- Line should NOT be kept on a reel - far too many moving parts. We
all know divers that have lost their SMB due to the reel jamming
Spools are a better solution, with less to go wrong, but still not
considered minimal enough for a true DIM diver - all that a diver
really needs, after all, is line. Spools and clips are an encumbrance
and source of failure points.
Line should therefore be kept stored in the standard "Ball of string"
configuration. Unraveling during lift bag deployment is utterly
jam-free, as the ball simply spins around to release line.
- The DIM drysuit has no pockets, as these interfere with both
streamlining and minimalist principles. The line and lift bag are kept
instead in the undersuit pockets. Since a lift bag is used only in the
event of a drysuit leaking, it is evident that water will already be
inside the drysuit, so unzipping the drysuit to extract the line is no
hardship. For this reason, DIM divers use front-zippered suits only.
- A DIM diver will still need fins, of course. However, spring-straps
should be avoided as much as regular ones. Only fins which can be used
without any fin straps at all should be considered. Replacing weak
straps with stronger ones will never be as effective as simply
ensuring that you do not need the straps in the first place.
- Seeing on a dive is, of course, a concern to all divers. There is
no point in diving if you can't see the bottom. The first step in
eliminating this problem is, of course, carrots - a DIM diver will
have a diet high in carrots, to ensure his night vision is as good as
possible. This cuts down on the number of dives where a light source
must be carried.
However, some dives absolutely cannot be done without carrying a
source of light. Once again, DIM divers have no truck with commercial
rubbish. Traditional torches are, of course, highly susceptible to
failure - batteries can go flat, bulbs can blow, the whole unit can
leak, and so on.
- Instead, a DIM diver carries an oil lantern. A far superior system,
light is provided simply by the flame. The lantern has a flint-powered
lighting system inside, which will produce sparks even when wet. Once
lit, the lantern provides enough light for a diver to navigate by,
without going to the pointless extremes of the electric lights used by
Obviously, DIM lights need a continual supply of Oxygen to keep the
fire alight. An oral inflation unit is therefore attached which allows
the diver to breathe into it regularly, providing enough Oxygen to
keep the flame burning. This is not such a hardship as it might seem:
On shallow dives, EAN mixes ensure plenty of Oxygen. And on deeper
dives, more gas is present in the lamp's internal volume due to air
The oral inflation unit, of course, might be seen as a failure point
by some, as it could allow water in as well. However, this is of no
concern: Oil and water do not mix, and oil floats, therefore any water
that enters the unit will simply sink to the bottom, out of the way.
- A DIM diver's mask is also different to other divers. Like his
fins, a DIM diver will have no strap on his mask. Instead, he keeps
the mask attached by making use of the mask squeeze phenomenon -
enough air is exhaled into the mask to prevent discomfort, but not
quite enough to allow the mask to fall off. It is important that a DIM
diver use a very well-fitting mask for this reason.
This short overview of DIM diving is provided as an insight into the
DIM movement. If you are attracted to the idea of true minimalist
principles and the level of safety that it provides, then visit the
DIM website for a list of courses.
Just imagine the day when you can announce to the world: I am a DIM