Light Monkey
SALVO (Light MonkeY) 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 don't know it, it's 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 policeman's 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 didn't expect it. I wouldn't 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 it's
an expensive lamp to flood.
Beam
At first, the Salvo didn't 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 didn't turn a night dive into a day dive.