How to Choose A Dive Light for Murky Water?

[Diving loved man]

Warm, clear blue water and a visibility of at least 20 meters, that’s what you expect when going through the dive magazines. But is it always a reality? Unfortunately, the answer to that is ‘no’. We’re not all that fortunate to live in a tropical dive paradise. Nonetheless, diving is also fun under less preferable conditions. For example, when the visibility under water is only around 1 to 2 meters, or when the visibility is unpredictable.
Less visibility has its implications. It’s not just that you cannot see things that are just a bit further away, it will also block the sunlight much more. So, under water it will be much darker – if indeed not pitch dark – than compared to those warm and clear tropical waters. And it’s even not comparable to a night dive in those waters. During a night dive in clear water, you just switch on your dive light and you can still see as far as the light reaches.

In murky water, things are different. Would you use a dive light with a wide beam, like for example the OrcaTorch D710V with it’s 120° wide beam, it’s more or less like driving a car in the fog with the cars high beam on. The light will reflect on all the fog particles and will basically ‘blind’ you. As if you’re driving against a wall. Under water with a wide angle torch the same will happen. It’s more or less: the more light your wide angle dive torch produces, the less you will see. More light just means more reflection.

The solution is however simple. Of course you want sufficient light, so choosing a torch with a wide light beam but less lumen is still not the option to go for. What you really need is a dive torch with a narrow light beam. Obviously, there will still be reflection of the light on the particles that are in the water. But by holding the light for example just below you or to your side, the angle from which you look will differ from the angle of the light itself. So, the reflection will mainly be in the direction of the torch and not in the direction you’re looking from.

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[grantmac]

Cool advertisement.

In my experience Orcatorch have a rather wide spot compared to others of the same "width".

Rather specific the Dive Rite 1000-6 is much tighter and has a constant output for the same or less.

 

[buddhasummer]

It was a sneaky advertisement. I didn't realise until the end. Well played sir.

 

[buddhasummer]

And the reason/motivation is?

 

[Telvar]

To each his or her own of course, but this is pretty lame. Not only bacause it's nothing but a thinly veiled advertisement and thereby inherently misleading/guiding, it's also at the very least incomplete.

As an active diver in murky waters, I agree that a wide beam torch is generally a bad idea, but narrow isn't one thing. what is narrow, is that 5 degrees, 8 degrees?

A better answer to the invented question would be: the more murky the water, the more narrow a beam has to be for just visibility, but I wouldn't say that work in every instance (for instance, laser is very tight, but has little use providing light, to take an extreme example). But it's not just beam width that is important. if visibility is 30m and it's dark, you don't need a 2000 lumen lamp, that's overkill. In murky water, however, 2000 lumen is adequate.

So, generally speaking it's: the murkier the water, the more narrow the beam and the more powerful the torch needs to be. Torches with variable beam width can be very good. I've been a happy user of the Mares 20rz, which has just that. But to be honest, I used that functionality infrequently. And although Orca makes pretty handy torches, the beam quality (in this case having a nice even light cricle) can be better.

 

[p_kos]

For low vis diving you need a light with a narrow (6-8deg) beam AND as little spill as possible. The best light I’ve seen used in these conditions is the Halcyon Focus set to tightest beam. It has virtually no spill and penetrates very well. I have an Orcatorch and it has to be powered down in murky water because of too much spill.