Strobe Lights and Night Diving

[Doctorfish]

I disagree with geffenk. "Basic navigation" at night can be very difficult and having a personal strobe tied off at an exit point in my opinion, is a safety measure, not an indicator of lacking skills. If a current comes up during a night dive or visibility deteriorates dramatically, it's very comforting to know exactly when to turn for shore. I've been out on several night dives that went bad unexpectedly and wished I had a strobe at the time. Now I use one on every night dive.

 

[KeithG]

I disagree with geffenk. "Basic navigation" at night can be very difficult and having a personal strobe tied off at an exit point in my opinion, is a safety measure, not an indicator of lacking skills. If a current comes up during a night dive or visibility deteriorates dramatically, it's very comforting to know exactly when to turn for shore. I've been out on several night dives that went bad unexpectedly and wished I had a strobe at the time. Now I use one on every night dive.

We disagree. Which is good! Since it may foster some discussion that we can learn from. Maybe?

For me, night dives are simply low viz dives (except for where your light is pointing at right now). As a vacation diver I have never been subjected to "real" low viz conditions. So I believe I have no real "low viz" experience. My claim is that if it is "required" for a night dive it is also "required" for a low viz dive as the conditions are very similar.

My night dives are all very dark high viz situations. At night i use the same navigation "rules of thumb" that I use during the day: identify a significant underwater structure belonging to my entry point. This will be my exit point at the end of the dive. Regardless of the time of day.

So i claim people blindly using strobes at night are just lazy. And maybe a bit too complacent?

What say you?

 

[tursiops]

We disagree. Which is good! Since it may foster some discussion that we can learn from. Maybe?

For me, night dives are simply low viz dives (except for where your light is pointing at right now). As a vacation diver I have never been subjected to "real" low viz conditions. So I believe I have no real "low viz" experience. My claim is that if it is "required" for a night dive it is also "required" for a low viz dive as the conditions are very similar.

My night dives are all very dark high viz situations. At night i use the same navigation "rules of thumb" that I use during the day: identify a significant underwater structure belonging to my entry point. This will be my exit point at the end of the dive. Regardless of the time of day.

So i claim people blindly using strobes at night are just lazy. And maybe a bit too complacent?

What say you?

You are describing several very different conditions. Firstly, night is not "low viz" as you describe it; viz has to do with distance that you can see something and make out what it is, so your clear-water night dives are "narrow viz" (where your light is shining) but not low viz. Low viz can easily happen in the daytime....algal blooms, sand or silt stirred up in the water, runoff from a rainy day...and for really low viz a strobe does not help much at all, but it does help.

Secondly, you can see a strobe at night farther than you can see with your hand-held light.....regardless of whether the viz is good or not. The strobe light only has to go one-way through the water, whereas the light you are carrying has to go two ways, and the strobe is flashing which helps to pick it out at a distance.

Yes, navigation at night without a strobe is usually possible in decent viz, but is always more certain with the strobe. My preference on night dives is a strobe at the boat/exit-turn but natural/compass navigation as a primary or backup tool, since it is more robust when usable but is not as easy (or as accurate!) if the strobe is working. Think of your natural/compass navigation skills and the strobe as like having two lights at night; the redundancy is what keeps you safe.

 

[KeithG]

You are describing several very different conditions. Firstly, night is not "low viz" as you describe it; viz has to do with distance that you can see something and make out what it is, so your clear-water night dives are "narrow viz" (where your light is shining) but not low viz. Low viz can easily happen in the daytime....algal blooms, sand or silt stirred up in the water, runoff from a rainy day...and for really low viz a strobe does not help much at all, but it does help.

Secondly, you can see a strobe at night farther than you can see with your hand-held light.....regardless of whether the viz is good or not. The strobe light only has to go one-way through the water, whereas the light you are carrying has to go two ways, and the strobe is flashing which helps to pick it out at a distance.

Yes, navigation at night without a strobe is usually possible in decent viz, but is always more certain with the strobe. My preference on night dives is a strobe at the boat/exit-turn but natural/compass navigation as a primary or backup tool, since it is more robust when usable but is not as easy (or as accurate!) if the strobe is working. Think of your natural/compass navigation skills and the strobe as like having two lights at night; the redundancy is what keeps you safe.

good point about "narrow viz". i will have to remember that. it is a much more appropriate anology that i came up with.

i still believe a stationary exit strobe is a gear solution for a skill problem. do you use a strobe during the day for low viz?

 

[tursiops]

do you use a strobe during the day for low viz?

No. It really doesn't work very well unless it is also dark or the strobe is incredibly bright. There has been the occasional daytime dive in very poor water (like strong algal blooms) so it is pretty dark at depth where a strobe might have helped.....

Most of my really low viz dives are done using reels and a guideline!

 

[KeithG]

i believe i may also be making an assumption that may not hold for some night divers. for me, the "bottom" at my entrance exit point is always shallow.

this means that i am always able to navigate back to the exit by staying close enough to the bottom that i can detect landscape formations i saw on my way out. i am not trying to free swim in the black wi no references to find the exit point. my worst case would be performing the last vertical ascent with no references. but at this point i have already located my exit point. i am simply getting out of the water now.

 

[Doctorfish]

Some of the shore night dives I do are in coral formations that are less predicable. Hence the desire to have a strobe reference point, just as you would use for a boat night dive.

 

[Basking Ridge Diver]

I use a strobe on the bottom of my dive flag while diving inlets at night in NJ waters. Viz can be about 5 to 6 feet or less depending on the water/weather conditions - the strobe can generally be seen from 30 feet down most of the time.
If my son or buddy gets separated from me which has not happened it is an easy way for them to find the flag and to find me. In an inlet with currents the fishermen get to see the strobe from shore/jetty and at least give them a heads up I am heading their way. I try to avoid hitting their lines when I can - coexist with the fishermen and I have not had any issues to date.