DIVE LIGHTS

The light below is designed as a back-up light and is made from a single, milled piece of a very tough plastic called Delrin.  Note that there is no switch as this is a common failure point.  The light is switched on by turning the bezel.
The backup light is neatly clipped to the shoulder D-ring and lies in line with the webbing.
For open water dives is using two of them.  For cave diving and wreck penetration I would use two of them as the consequences of a light failure are much more serious and one more backup in the dry suit pocket.

Location of backup light

This back-up light costs 80 Euro.  Although this is not cheap for a small light you are paying for quality of materials.  The assembly inside and bulb are standard (Underwater Kinetics) parts that cost 10 Euro.

If your main light failed and you had to go to your back up, turn on the back-up light BEFORE you unclip it.  This is in case you drop it.  If you drop a light that is switched on you can see it easily.  If you drop a light that is switched off you can’t see it easily and inside a wreck or cave you don’t want to be digging around looking for your back-up when your main light has failed.  Common sense, but you will be amazed how this isn’t many people’s instinctive reaction.

The back-up light can suffice as your main light but if you want a brighter light you are better to go for a canister-type light with umbilical cord and light head.  There are hundreds of lights on the market but most of them involve holding the light with the palm of your hand.  This effectively means that you either lose the use of one hand or you have to let go of the light in order to do something with that hand.  Most people therefore attach their light to either a lanyard or a stretchy cord attached to their stab jacket.

The light head shown below uses a “Goodman handle”. You can immediately see that even whilst holding the light you have full use of your hand.

Head of primary light with goodman handle and separate canister

Depending upon your level of diving you might not be that worried about this, but if you either intend to, or are currently involved in, more technical dives you will greatly appreciate this advantage as the number of tasks during the dive increases (reel work, gas switches etc).  Even if you don’t intend to get into this sort of diving, there is something to be said for being able to inflate your wing/stab AND dry-suit with one hand and STILL have the other hand free to do other things (assist buddy, tie in shot, pull yourself down shot line etc).

The advantage of using a canister for the battery is that you can get better burn times for any given wattage of bulb (you can therefore use brighter bulbs for any given burn time) and you do not have to hold a large light (with battery) in your hand.  The canister is attached to the waist strap on the right hip.  Here it is out of the way and because it is in the slipstream of the right arm and shoulder, it doesn’t increase drag or present any entanglement points.  The in-water weight of the canister can be taken off your weight belt.

Mounting a canister on your cylinder has several disadvantages:

1. You can’t remove it by yourself if you had to.
2. It creates a very bad entanglement point in a place that you cannot reach (bear in mind 1) above).
3. It is situated in a place where is directly increases your profile thus increasing drag significantly.
4. If you mount it on the side of the cylinders it will affect your trim as the weight is further from the central axis of the body (tendency to roll).  If you mount it between the cylinders you have increased the headroom you need.

Backup light