Scuba diving is swimming under water with a scuba system,
which consists of an air tank (containing air and not
pure Oxygen like some people think), a regulator, a
weight belt, and
an assortment of other things that can be optional.
Equipment
Note that I said other equipment
can be optional. Most
of the time you will scuba with the following things:
- Regulator - You breathe out of this thing. It takes
the high pressure air coming out of the tank, and reduces
it to the same pressure as the water around you.
- Air tank - This contains the air you breathe.
- Weight belt - Most of us float in water, at least partially,
add to that an alloy tank which is positively buoyant, perhaps
a wet suit, and you'll find it hard to get down, so we wear
lead weights around our waist to counteract the positive buoyancy.
- BCD or BCU - a Buoyancy Control Device aka Buoyancy Compensator Unit,
this is a "jacket" that
can be inflated and deflated to control your accent and
decent into the underwater abyss.
- Face Mask - Ever noticed how little you can see normally
underwater. So have scuba divers, so we wear face masks.
These masks (unlike normal swimming goggles) cover the
divers nose as well.
- Fins - Its damn difficult to move when your main
propulsion device is as small as your foot, so you
almost always wear fins that help your propel along.
- Wet suit - Not always needed if you happen to be
fortunate enough to be diving near the equator, however
90% of the time, you'll be wearing at least a half-suit
(one which only covers half your arms and legs).
Wet suits can range from 3mm thick to the "I'm warmmer
than toast" 7mm thick. When diving in colder conditions,
a wet suit hood is almost always a requirement, since
you loose most of your heat through your head.
- Snorkel - Not always needed, but helps conserve
air if you are doing a long surface swim.
- Octopus or Octi - Again, not always needed, but I myself never
dive with a partner who doesn't have one. Its a spare
regulator attached to your air supply, in case your partner's
decides to give up, or he's been sucking too much.
- Knife - Not for attack or defence mind you. A dive
knife is mainly used to either cut yourself loose if you
get caught up in fishing line or kelp. Can also be used
for prying oysters, but that will damage your blade :).
- Gloves - When its cold you need these, however some
dive areas ban them since people are more likely to touch
things they shouldn't (eg delicate coral) when wearing
gloves.
There are also many other items which people take, though
this list covers the ones I usually take on trips in
New Zealand.
(Which has one of the top 10 dive spots in the world,
the Poor Knights.)
As for the person who mentioned you can't hear anything,
this is not quite true. If you are sucking (breathing)
hard, then yes, the noise of the air through the regulator
can be loud, however all you need to do is relax and breathe
slower. It is relatively easy to get your breathing down
to four breaths per minute if you just sit at the bottom.
Once you are that slow, you can hear all sorts of things,
even fish farting!
Limits & Dangers
As for limit, recreational scuba divers (also known
as open water divers), usually stay down between
30-50 minutes (depending on how deep and how fast
they suck) and their maximum depth should
be limited to 40 meters. After this point, things get
a bit more dangerous.
As for the dangers of diving, the most prevalent and
common danger in diving is called decompression sickness
(aka the bends), it occurs when you ascend to fast and
nitrogen bubbles begin to form in your bloodstream. How
fast is too fast depends on many things, but generaly on your
depth, time down and previous dives in the last 24hrs.
Divers
either use a dive computer or decompression chart to work
out their residue nitrogen levels in their blood. The general
rule of thumb for ascending in recreational diving
(where you don't exceed decompression limits)
is no faster than your air bubbles ascend.
Another danger which occurs much more often than it need
do is usually the cause of decompression sickness, and that
is running out of air. When divers run out of air, they
tend to panic, and ascend rapidly, dying later of the bends.
This is an important reason why you should always dive in
pairs, since you can breathe off your buddy's Octi if you
are silly enough to suck your tank dry.
Contrary to popular belief, shark attacks are a very
rare danger when diving. In fact sharks tend to stay away
from divers.
There are many other forms of scuba diving which I
have not mentioned here, where you can exceed
the some of the limits I mentioned relatively safely.
Why scuba?
There are many reasons for scuba diving, and probably as
many different types of scuba diving, but here is a
summary of some of the more common reasons.
- Recreation - You may think its fun sitting in a boat
with a fine line dangling in the water, but it can be
much more fun if you are down their swimming with your
intended prey. :)
- Sport - Its a sport, you get good at it, you dive
in different places, with different people, you exceed
limits that you've never exceeded before.
- Photography - It's a whole new world down there, and
for most people, one which they will never see. So capture
its essence and show your friends.
- Food - Yes, you can hunt down their, though there
is a whole big debate about what you can and can't do,
and there are numerous laws governing what you can
and can't kill.
- Exploration - Sometimes you can hunt for non-living
things, explore through shipwrecks, even find sunken
treasure. :)
- Because its just fun - Hey, unless you happen to be
an astronaut or a pilot, you aren't ever going to
get another chance to experience weightlessness.
Cost
Ok, so it is pricey. The costs of
the gear can depend on what you get, and where you get it.
And you really can't get it in parts, unless you hire
the gear you don't have.
For me, in New Zealand, NZ$2000 set me up with all the
gear I needed, however ymmv (Your mileage may vary).
More information
Contact your local dive shop for information on
learning to dive. Once you've done the basics, then
you can come on the net and look at tips others have
produced at your local search engine.