Appeared in DIVER November 2007

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John John Bantin has been a full-time professional diving writer and underwater photographer since 1990. He makes around 300 dives each year testing diving equipment.

LIGHT SALVO HID

SALVO IS A BRAND OF DIVING LIGHT held in high esteem by those divers trained by GUE, a Florida cave-diving agency that has branched out into leisure diving. If you dont know it, its the guys who used to claim they do it right.
GUE (Global Underwater Explorers) specifies the equipment its divers should use. It had strong ties with the Halcyon brand, for which one Barry Miller made the lights.
When Barry decided to branch out and make lights under his own brand, Salvo, Halcyon objected and legal shenanigans ensued, ending up with someone getting a jail term.
Salvo continues making lights to the same high manufacturing standards. This HID is very compact. About the size of a policemans torch, it is machined from a lump of Delrin and its chassis is very high-quality. It has considerable shop-counter appeal, but is also extremely light in weight.
An optional accessory is a Goodman-style handle that the diver wears on the back of his hand. This clips on in a satisfying way. What a pity the lamp falls off it so easily under water, and how glad I am that I took the precaution of adding a lanyard (not supplied) to dangle the lamp from my wrist when this happened

Light Source
The Salvo uses a 10W HID bulb that, typically, takes time to warm up to full output. The life expectancy of an HID bulb and ballast depends more on how often it is fired up than on actual burntime. Never switch off an HID bulb before it reaches full working temperature - turn it on just before entering the water and leave it on until you are out.
Its output is equivalent to many times the wattage of a conventional tungsten bulb. It is very bright indeed.

Power Source
A lithium-iron battery powers this lamp. It combines the advantages of small size and weight with a good power output of more than two hours, and you can recharge it very quickly at any time or state of charge without it creating a memory-effect.
The disadvantage is that lithium-iron batteries do not take kindly to immersion in salt water, so ensure that the O-rings that keep the lamp watertight are undamaged and properly lubricated, and that they sit correctly in their grooves.

Switching
You turn on the Salvo HID using a knurled twist-grip to make a battery contact. Switch it off by turning it the other way.
This is the same action needed to take the lamp apart to charge it - you continue to unscrew it until it comes apart.
I am suspicious of this method which, although simple in construction, always leaves an element of doubt.
I had the lamp turned off, but it came on when I didnt expect it. I wouldnt dare to switch it off under water in case I turned too far and flooded it. Though it is protected by double O-rings, a lot of divers have the dexterity of an ape wearing boxing gloves. The limitation of use of an HID light could be said to preclude this problem, but its an expensive lamp to flood.

Beam
At first, the Salvo didnt seem much brighter than the multi-LED light I used alongside it, but gradually it warmed up to produce a narrow yet piercing blue beam of very high intensity.
Using it in clear water, the low colour temperature of the beam enabled it to travel a long distance without being absorbed. It was another of those light sabres in a nice compact form. Its size belies its performance.
There was also a very comfortable peripheral halo of light. So while the lamp was very bright, it didnt turn a night dive into a day dive.


Divernet Divernet
SPECS
SALVO HID LIGHT
PRICE £286
BURNTIME 135min
EXTRAS Goodman-style handle (25)
WEIGHT 0.48kg
DEPTH-RATING 125m
CONTACT www.divingniknaks.com
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