Somone change my mind.

[WV Diver]

I have never been one to advocate the twist on/off lights. I think they are the biggest failure point of lights.

They can be twisted on by mistake, especially in a dive bag during transport or very easily flooded just turning it on or off. I had flooded one back in the beginning of my dive career and swore off of that junk right then. As I have gained experience over the years I have never gone back to a twist on light.

After getting involved with tech stuff recently I still cannot understand why a DIR or a good tech diver would want to carry something that is so prone (IMO) to failure.

I just don't understand why the tech crowd would embrace such a thing as a twist on light. There has to be a better reason than a "switch is a failure point". It certainly seems to me that a switch (especially one that locks on and off to prevent it from accidentally coming on) would be a far better choice than something you have to keep a constant watch on.

To me this is like saying, I'll stick to my tables because my computer is too prone to failure.

Let the flaming begin.

[comet24]

I am not a DIR diver but I have an old twist on light I use sometime. Only takes about a half turn to turn it on off. It will not turn on it's own. To flood it you really need to turn that thing way past what you need to turn it on/off. Need need to flame you can dive what you want for your own reasons.

I don't have on because failure points or DIR just happens to be how one of my lights was made.

[Rainer]

I have no interest in "changing your mind". That said, I'll tell you why I have no problem rocking a pair of twist on backup lights. First, mine require just a minor turn to twist on, at which point the threads are fully engaged. To flood it, I'd need to make something like five complete turns in the opposite direction. If one cannot figure out the difference, he shouldn't be tech diving. Second, they won't accidentally twist on underwater with increasing pressure like the H Scout lights. If for some crazy reason they did turn on, my team would notice within seconds. As far as turning on in a dive bag, I keep my lights attached to my harness. They don't move until I need them and it reduces the chance of the light accidentally coming on in transport. We check our backup lights before diving. We have spare batteries. It's just a non-issue. Four, a double o-ring sealed twist on has only one means of flooding, through the front of the light past those two o-rings. Unless you're a complete twit, you won't twist off the head of the light and thus you cannot flood such lights. They're rock solid. Taking a perfectly closed system then drilling a hole into it to add a dynamically moving switch is unideal. It's proven out by the numerous reported failures of such designs. Both the hole created by adding the switch, and the more complicated switching mechanism (compared to the simple twist mechanism) are failure points that many tech divers (DIR or not) would rather do without. As the depth of the dive increases, and pressures build, these potential failures become more and more serious.

For all these reasons, I have no interest in mechanical switch based back up lights.

[rox@ucf11]

how about a magnetic switch?

[Rainer]

Personally, I'd probably have no issues with one, but the switch itself is still prone to failure. The light won't flood, but it might not turn on either. If/when they become more reliable, they'd be a valid option in my mind. For now, I'm happier sticking with twist ons.

[buddhasummer]

Originally Posted by Rainer

I have no interest in "changing your mind". That said, I'll tell you why I have no problem rocking a pair of twist on backup lights. First, mine require just a minor turn to twist on, at which point the threads are fully engaged. To flood it, I'd need to make something like five complete turns in the opposite direction. If one cannot figure out the difference, he shouldn't be tech diving. Second, they won't accidentally twist on underwater with increasing pressure like the H Scout lights. If for some crazy reason they did turn on, my team would notice within seconds. As far as turning on in a dive bag, I keep my lights attached to my harness. They don't move until I need them and it reduces the chance of the light accidentally coming on in transport. We check our backup lights before diving. We have spare batteries. It's just a non-issue. Four, a double o-ring sealed twist on has only one means of flooding, through the front of the light passed those two o-rings. Unless you're a complete twit, you won't twist off the head of the light and thus you cannot flood such lights. They're rock solid. Taking a perfectly closed system then drilling a hole into it to add a dynamically moving switch is unideal. It's proven out by the numerous reported failures of such designs. Both the hole created by adding the switch, and the more complicated switching mechanism (compared to the simple twist mechanism) are failure points that many tech divers (DIR or not) would rather do without. As the depth of the dive increases, and pressures build, these potential failures become more and more serious.

For all these reasons, I have no interest in mechanical switch based back up lights.

Agree 100%, I own a solus backup and DR LED 500 one with magnetic (solus) and one twist (LED 500), there is absolutely no way on earth the DR is gonna twist on or off by accident in your bag or harness or where ever else you carry/store it, it requires both hands to twist and a reasonable amount of force. The solus although magnetic its still twist on and off and
will not turn on or off without using two hands and again a reasonable amount of force. The DR, as Rainer has stated with other twists, in order for it to leak upon activation or deactivation you would need to twist it at least 4-5 turns. I agree again with Rainer I guess the magnetic switch mechanism could fail but as said that would only result in not on or not off but would not cause the light to flood. Im not sure as to the quality of lights you have seen or used but the potential problems you speak of I think would be rare in a quality light with maintained O rings and used as per manufacturers instructions. I would be more apprehensive purchasing a light with a switch on/off. Just my opinion based on my experience hope it helps.

[cummings66]

WV Diver, do you own a twist on or have you just formed an opinion based on conjecture?

I ask because I own one and it absolutely will not, could never, and will never be able to turn on without a person making it happen. It takes very little effort in terms of how much twist you need to use, and with double O rings there is no risk of leakage either.

I have a mechanical switch on a dive light, I've had far more problems with switches on lights than I've ever seen on a twist on light. Of the two technologies, twist on is more robust and able to be counted on. That is why the technical community uses them along with GUE. They are better.

[wgt]

Originally Posted by cummings66

WV Diver, do you own a twist on or have you just formed an opinion based on conjecture?

I ask because I own one and it absolutely will not, could never, and will never be able to turn on without a person making it happen. It takes very little effort in terms of how much twist you need to use, and with double O rings there is no risk of leakage either.

I have a mechanical switch on a dive light, I've had far more problems with switches on lights than I've ever seen on a twist on light. Of the two technologies, twist on is more robust and able to be counted on. That is why the technical community uses them along with GUE. They are better.

An issue pertaining to the ease/difficulty of accidental/incidental lighting of the twist light (e.g., during travel) is who has been handling the light. When the owner exclusively manages the device, they would tend to adjust the twisting module to minimize probabilities of accidental lighting. However, TSA agents, for example, often inspect devices (particularly when entering the US from Central America ). The device, under these conditions may be poised to light. Some airlines may have a rule against carrying lights with batteries inside. For those airlines that do not enforce such rules, a third party might indeed cause a problem. Another potential impact of third-party intervention is the accidental introduction of debris onto an o-ring. This might faciliate flooding.

When third-party involvement is possible, I would advise traveling with the batteries out of the light and inspecting/servicing of o-rings before use. Otherwise, I would not be uncomforatable with a twist-on light. As for non-locking toggling switches, a little piece of duck tape can work wonders to prevent accidental lighting during travel.

[chinacat46]

Originally Posted by wgt

As for non-locking toggling switches, a little piece of duck can work wonders to prevent accidental lighting during travel.

Why a duck? Why not a chicken?

[wgt]

Originally Posted by chinacat46

Why a duck? Why not a chicken?

Thanks for catching the booboo. Besides, all tape sticks like chicken tape.