Okay, to summarise what was found on that thread:

Princeton Tec Aqua Strobe - 3 Mile (4.8 Km) Visibility
Apeks Torches - Apeks STROBE - 3.4 Km (2 Mile) Visibility
Inova 24/7 - Up to 2 Mile (3.2 Km) Visibility
ACR MS2000(M) - Peak Luminosity 250,000 Lumens
Visibility: Military tested at a distance of 6 miles (9.6km) on a clear dark night

Anyone have any ideas on how this compares to, say, a Nikon SB-600 Speedlight?

If you don't need the omnidirectional aspect of the strobe, I imagine you could get better (directional) results by holding it next to a signal mirror or a piece of space blanket/mylar reflector. (You could switch the strobe from one side to the other every couple of minutes, or even turn slowly in a circle, to get full coverage.) Of course, a camera flash is pretty unidirectional to begin with <img src="/images/graemlins/smile.gif" alt="" />

Well Nikon strobe would be visible up to 2-3 miles but the question is how you are going to do on battery life? I know that some of the survival strobes will run 12 hours constantly on the set of batteries how your nikon strobe is going to do? I shot weddings with my SB28 strobe and got about 2 - 3 weddings out of 4 aa. Thats about 300 pics per wedding which totals on 900 flashes using lithiums. Aqua tech strobe 70 flashes per minute; 1 AA Alkaline ; 8hr burn time. SO doing the math you got about 33000 flashes. You can pass out and strobe will still be functioning, you can pay attention to the surroundings and strobe will be going off on its own.

Yes if you have no choice photo strobe will do the job but regular survival strobe will be much better, cheaper and more efficient.

I wouldn't expect a camera flashgun to be better than a dedicated survival strobe, of course. But in a backpacking situation where you have to think carefully about how much gear you're going to carry, I might choose to leave a survival strobe off my list, whereas I might well take a camera along.

This is the reason I like Inova 24/7 so much because it is light weight and can double up as a flashlight, tent light, reading light, night vison light, emergency light and strobe.

O.K., you have sold me.
Where do I sign to get one (or more) ? <img src="/images/graemlins/grin.gif" alt="" />

Thanks for the input everyone. I think I'm going to order the ACR Firefly 2. It satisfies my need for light weight and small size, but does not compromise on light output. I will also equip all lifejackets with the smaller ACR C-Light. While I'd love to be able to put high output strobes on each lifejacket, cost is an issue...flying is so rediculously expensive it burns up far too much money allready <img src="/images/graemlins/crazy.gif" alt="" />

Found an interesting article on colors used for signaling and other applications.

Flashlight Filters

My interest in this is a filter for a flashlight used in a smoke-filled environment such as escape during a fire. I wanted to confirm that amber was the way to go.

~Sarah

While I agree fully that flying *is* ridiculously expensive, I'd recommend that you not shy away from high priced items...especially ones that are designed to save your life!

I'd like to give a recommendation as well...any "Doublefly" version of ACR strobes.

Why the Doublefly?

Say you're sighted by SAR, and now they've got a chopper hovering over your position. A strobe can be a bit annoying for the pilot that has to contend with whatever factors occupy their mind at that precise moment...trees, lines, whatever. In reduced visibility, a flash, or reflection of the flash, every 5 seconds, could possibly become a hazard in itself.

That's where the Doublefly comes in. You now have a constant, lower intensity light for SAR crews to pinpoint you without the light becoming a distraction.

I've also taken Matt's excellent advice a while back and picked up an Inova 24/7. It also allows you to switch between the strobe and a low intensity constant light, and also gives you a handy red mode for when you want to save your night vision. I wouldn't replace a dedicated strobe with it, though, but it makes a great backup & utility light.

The problem with flying is it's about as much fun as a human being can have (legal or illegal) and that makes it highly addictive.

I agree about not going cheap on life saving equipment. I fly a lot over Georgia Straight and a lot in the mountains and that's why I chose the ACR products. They are top rated and the Firefly2 is about as good as it gets for an emergency strobe. I also ordered the C-Light for life jackets for the reason you state...it would drive a helo pilot or SAR tech nuts looking into strobe for several minutes. The Firefly, I see more as a device to signal from a distance, or through a canopy of trees in failing light. I will continue to carry signal mirrors however, and would use them if light the was adequate...not to say I wouldn't also use the strobe...heck, I'd use everything I had to get rescued.