Primary Light
A primary light is one of the most important pieces of equipment when penetrating wrecks. A primary light is just that, the main light you’ll be using throughout the dive that will provide the light for you to see where you’re going. For this reason, you should purchase the best possible light you can afford.
Primary lights usually consist of a battery pack and light head, which are connected with a heavy-duty light cord. The battery pack holds the batteries, which are typically Gel Cell or NiMH rechargeable batteries. The canister should be depth rated to deeper than you plan on going and contain the on/off switch for the light. Light heads typically come with test tube or projector style bulbs and use 30, 50, or 100 watt halogen bulbs. Test tube style bulbs are more common and offer better lighting characteristics. HID (high intensity discharge) type light heads are latest and newest light system. They come with 10 or 21 watt HID bulbs. HID bulbs cast a whiter light and because of their low wattage rating get excellent burn times with either NiMH or Gel Cell batteries. Halogen bulbs cast a more yellow light and burn for less time with either Gel Cell or NiMH battery packs.
There is much more with respect to the technical aspects and operations of a high-end primary light, but these are some of the basics. For detailed specifications, burn times, and light configurations, consult the manufacturer.
Note: Once you get your own light, it’s important to burn test it. Don’t rely on the manufacturer’s specifications. Test the burn time your self so that you know exactly how long the light will last.
Primary lights are typically hip mounted on the waist strap of your harness and should be positioned under your shoulder so that they are streamlined. Some divers mount their primary lights to predrilled holes on the side of their backpates. This can also keep the light streamlined but can be harder to reach or remove if you needed to remove the light underwater.
Cost: $350 to $1,500