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Graham Kennedy wrote:I guess they just have to hope people attack them in good weather... because that thing won't work worth a damn in rain or fog.

Perhaps, but then again I haven't seen a report of the wavelengths used, as you seem to have.

It's infrared.

Graham Kennedy wrote:It's infrared.

OK, then, why would fog bother it?

Mikey wrote:

Graham Kennedy wrote:It's infrared.

OK, then, why would fog bother it?

The water molecules in fog are pretty good at absorbing infrared wavelengths.

^ What he said.

Also, can't help but notice that in all the tests I've seen of this thing, the targets are painted black. Like the boat in this vid :



I wonder how it performs against one that's painted white, or coated with a nice infrared reflector like aluminium.

Also, notice that the target there was 'ordinance" - i.e., a box of explosives. Meaning the laser didn't cause that explosion, it just set it off. And they don't even show you how much dwell time the beam requires.

All we really know about this thing is that it can make a small black box of explosives blow up when fired at it for an undetermined amount of time. But how does it do when it's fired at the non-explosive side of a even a small boat, though, let alone a steel warship?

It would be great if laser weapons have truly become a practical reality. I'm just a tad skeptical about it, is all.

In the video that Nutso posted, neither of the target vessels were black, and at least one of the target ordnance carriers was decidedly non-black. As to fog and rain, I think we may be greatly underestimating the amount of empty space in a fog bank or rainstorm, when viewed on a molecular level.

All that said, I'm still not defending this as a contemporaneous workable weapon system... even in the video which was decidedly skewed in favor of the system, there is much that remains to be desired in a front-line close-in to mid-range weapon system. Foremost in my mind is the length of time the operators seem to need to dwell on target before actually being able to fire accurately... one would assume that a beam of light requires precious little leading of the target. Primary among my would-be concerns, though, is this: is it any more useful than a conventional weapon? Is it a) more effective, or b) as effective but with less cost-per-shot or man-hours required for operation a/o maintenance? If it is simply as effective as a conventional weapon in the same role, but with no savings in operation, maintenance, or somesuch, than the whole thing is simply an expensive jerk-off session for some Navy brass-hole.

Mikey wrote:In the video that Nutso posted, neither of the target vessels were black, and at least one of the target ordnance carriers was decidedly non-black.

Actually look again - the boats aren't black, but the target mounted on the boat which is actually hit by the laser and explodes is black. Notice that the boats themselves are entirely undamaged by the laser, the only thing damaged is the little black box.

The aircraft looks grey, granted. But we have no clue as to the size of it, and again no clue as to dwell time on either.

As to fog and rain, I think we may be greatly underestimating the amount of empty space in a fog bank or rainstorm, when viewed on a molecular level.

How far away can you see car headlights on a clear night? How far away when it's foggy? And that's visible light - infrared absorbs better, one would think.

All that said, I'm still not defending this as a contemporaneous workable weapon system... even in the video which was decidedly skewed in favor of the system, there is much that remains to be desired in a front-line close-in to mid-range weapon system. Foremost in my mind is the length of time the operators seem to need to dwell on target before actually being able to fire accurately... one would assume that a beam of light requires precious little leading of the target. Primary among my would-be concerns, though, is this: is it any more useful than a conventional weapon? Is it a) more effective, or b) as effective but with less cost-per-shot or man-hours required for operation a/o maintenance? If it is simply as effective as a conventional weapon in the same role, but with no savings in operation, maintenance, or somesuch, than the whole thing is simply an expensive jerk-off session for some Navy brass-hole.

Right now, I think this thing is more for show, and money for defence guys, than anything else. I strongly doubt it's a practical weapon.

Graham Kennedy wrote:Actually look again - the boats aren't black, but the target mounted on the boat which is actually hit by the laser and explodes is black. Notice that the boats themselves are entirely undamaged by the laser, the only thing damaged is the little black box.

The aircraft looks grey, granted. But we have no clue as to the size of it, and again no clue as to dwell time on either.

One of the targets, one that looked like a group of rocket tubes on the second boat, was definitely not black. However, I hardly think that that's the most important takeaway from the video.

Graham Kennedy wrote:How far away can you see car headlights on a clear night? How far away when it's foggy? And that's visible light - infrared absorbs better, one would think.

Far enough, and comparing car headlights to collimated, coherent laser light is like comparing apples to stop signs.

The tubes were just the support structure. Look close, it's the little black box that is the target.

Far enough, and comparing car headlights to collimated, coherent laser light is like comparing apples to stop signs.

Not so much, since it's about the absorption of light.

Mikey wrote:

Graham Kennedy wrote:How far away can you see car headlights on a clear night? How far away when it's foggy? And that's visible light - infrared absorbs better, one would think.

Far enough, and comparing car headlights to collimated, coherent laser light is like comparing apples to stop signs.

You're right, it is very different. Since water is a better IR absorber and the laser will be of uniform wavelength the attenuation effect of the fog will be much more drastic on the laser. The coherence of the laser will have zero effect on preventing or aiding it's attenuation.

In the end, we don't have the details to judge. I guess they must think the thing at least has potential to be useful - even the US military isn't at the point where it's going to buy totally useless hardware, surely? But I suspect it's not a cool new weapon that's a big step up in capability over guns, more a development step towards something that may be worth having in future. But like I said, we don't have the details to do more than guess.

I know the cost savings are heavy; another article I saw said it would cost cents per shot, rather than however much shells cost.

Tsukiyumi wrote:I know the cost savings are heavy; another article I saw said it would cost cents per shot, rather than however much shells cost.

That, then, makes this interesting.

Tsukiyumi wrote:I know the cost savings are heavy; another article I saw said it would cost cents per shot, rather than however much shells cost.

I'd like to know the cost difference between the laser and the gun it is replacing, to see how many shots are needed to break even. The other stunt would be seeing how much maintenance is needed on the laser, so we can price out the salaries of people needed to maintain the laser vs the gun (I'll bet that lens needs a lot of cleaning). Even worse is if it uses its own chemicals to power the laser, so it still has a form of ammunition.

Now if it uses electrical power produced by the ship's generators, that would work nicely. One less form of ammunition to keep track of, and the ship's crew is already familiar with the turbines and the electrical generators.

Right now I'd imagine the laser costs a hell of a lot more than a CIWS, much as the first of any new military item costs a lot. Price will come down if/as they build more, though.