OW backup light strategy?

[Matt S.]

In open water night diving, what is the purpose of a backup light? I mean, do divers intend to finish their dive plan with the backup acting as primary, or do they just use the backup to safely end the dive as soon as possible?

If you keep going, don't you need a backup for your backup?

If you just thumb the dive, how much light do you need to surface safely?

I'm just trying to plan out future gear purchases for my wife/buddy and I. We have 1 HID can light between us now. The next light will probably be a handheld HID for her, since she doesn't seem to like the can too much. THEN I get to think about buying backups so we can learn night diving... hence my question about the strategy for using a backup.

 

[BDub]

Hey Matt-

Generally speaking, if the primary fails, the dive is over. The backup is used to help with the exit/ascent and maintain communication with your buddy/team.

Brian

 

[Matt S.]

Good, that sounds sensible. I don't want to carry backups for backups for backups.

 

[ArcticDiver]

Think through the kind of dives you do. If it is a shallow moored boat dive terminating the dive on primary light failure and using the one backup per person is probably ok.

But, a night drift dive is another matter. There three lights per person is the safe thing. Situation: You two are drifting. Despite your best intentions you get separated. Then backup#1 fails. If you don't have a second backup you are in the dark with no way not only to see your gauges, but no way to signal the boat. Unless, wonder of wonders, you have backup#2 to see and signal with.

Due to separation risk both divers should be able to abort the dive and recover to shore or the boat independently when all else fails. That means for night dives 3 lights per person. Probably you will go for years; posssibly your entire diving career and never need all those lights. But, if you do......

So: For moored or sheltered night dives: 2 lights per person. For all others: 3 lights per person.
My goodness; backup lights are cheap. Number 3 can be as small as a Pelican MightyLite AA for $20 or less.

 

[TSandM]

Matt, I wouldn't buy a handheld HID light, especially given what I recently learned about them. Buy a Photon Torpedo with the LED upgrade -- It will cost you less money, and it's darned near as bright, with a far longer burn time and sturdier construction. It will also serve as a backup light when your wife decides she wants an HID of her own (and she will ).

If you carry one backup light, and that's what most people do in open water night diving, that backup light is to end the dive. It allows you to see your gauges and to communicate with your buddy. I've done dives where the primary failed early on and we continued the dive, but that was an experienced diver in a situation where we both had backups and had a second light failed, we would have ended the dive. We were also in a site both of us knew very well. It's all about risk assessment. The principle is to have three sources of light, but that's for overhead environments. If you get cut off from your buddy and are completely without light at night in open water, you CAN ascend. Maybe you can't measure your ascent rate, but you'll end up on the surface where you can breathe. So the consequences of complete light failure in open water are not nearly as severe.

 

[BDub]

Matt, I wouldn't buy a handheld HID light, especially given what I recently learned about them. Buy a Photon Torpedo with the LED upgrade -- It will cost you less money, and it's darned near as bright, with a far longer burn time and sturdier construction. It will also serve as a backup light when your wife decides she wants an HID of her own (and she will ).

I agree 100%.

 

[Mo2vation]

I have two PT's. Had them for years. Just purchased two (price reduced recently) LED upgrade modules.

OMG - what a difference.

They are fine, fine back ups. Like most back up lights, they rattle and can become intermittent. I stuffed a McDonalds drinking straw in between the batts and the inside wall of the body. They are now silent, and I can shake them voilently and they no longer flicker. They are positive on and off. What an improvement.

I love mine.

Diving with my regular dive buddy, each of us have completed hour+ dives where our HID's failed (or we forgot to test-strike them) early or on the way thru the surf. No biggie if you're tight.

---
Ken

 

[texdiveguy]

Dude, go with the Gulftek PT LED light...at $138 its a good deal.

 

[jtivat]

Matt, I wouldn't buy a handheld HID light, especially given what I recently learned about them.

I am interested in what you learned I do prefer a can when tek diving but in a OW warm dive I would take my hand held 10w DR over the can any day.

 

[TSandM]

I read a thread involving a hand-held HID light, in which the OP described being unable to strike the light, despite the batteries registering near complete charge. The company (which was not identified), when contacted, said this was typical for HIDs -- The voltage required for striking is far higher than that required for ongoing light, and they said their lights were generally only good for a half dozen strikes before the batteries would have to be replaced.

HIDs also have high current requirements, so they need a lot of battery to have significant burn times. The LED backups have burn times that can go as long as 50 hours for the 1W lights. I like that better.