Yet another required piece of safety gear... a LASER!

[Beiji]

It sounds like they didn't leave anyone on the boat. If that's the case, maybe the more important thing to learn from this story is to make sure someone stays on the boat.

 

[John C. Ratliff]

I have been a laser safety officer in a previous life, and know a bit about them. Laser pointers can be fairly powerful. Lasers are coherent light, meaning that they are a single wavelength, and that the beam is aligned on a single axis. The word "LASER" actually stands for something; Light Amplification by Stimulated Emission of Radiation. A laser beam, when it enters the eye, does not focus to an image, but instead to a single point on the retina, thus concentrating the light beam onto a very small area of the eye's retina. This can cause tissue damage, and at the very least blanches the cells so that they cannot "see" anything for a time--at least a minute.

Green laser pointers are usually a Class IIIA laser device, which means that the blink reflex should be protective of laser retinal injury, but it will blind a pilot in an aircraft for a period of maybe a minute. If it is a Class IIIB or a Class IV laser product, then retinal injury will likely occur. These lasers are required to have a warning label attached, and this one does not have it. This looks like a pretty "beefy" laser, and so it is possible that this is a Class IIIb or even a Class IV laser product. I would not want to use one of these underwater, as it is not a good illumination device. The beam is too small, and too bright.

In the USAF, we normally carried a Mk 13 day/night flare taped with masking tape to our leg knife. I used one in Okinawa on a dive search mission to be picked up. A helicopter had crashed into the ocean, and we were diving to try to find it. Here's what I wrote in my memoir (which I'm still working on) concerning the third day of this search.

I don’t know what they did, but the next day we were out of the LARK, and onto a large Okinawan ship. They took us out to the site for a dive in shallower water. As the ship dropped anchor, Devoe and I prepared to dive. We dressed in our wet suits, strapped our dive knives with a Mark-13 Day/Night flare taped to it onto our legs, and put on our LPU’s (underarm life preservers--we did not wear “life vests” like the Navy divers, but LPU’s served the function even better, giving us two inflatable bladders instead of one smaller bladder). We waddled to the doorway in the heavy twin scuba, which was open and put on our fins. Devoe went first, jumping into the water from over five feet in the air. I watched him enter the water and noticed that he immediately was swept under the ship. Since we were buddies, I also jumped a second after he left sight. A swift current also swept me under the ship, and I was surprised to see that the ship had a completely flat bottom. It was no ocean-going vessel. Devoe was about forty feet from me, and about twenty-five feet down. I swam to him, and stopped swimming. The current was very strong, at about four knots. We could not swim against it, so we surfaced. The ship was already a hundred or so yards away. We decided that we did not have an emergency, and would ride the current a ways to see if we could spot the helicopter.

We swam down to the bottom, and drifted with the current for about ten minutes. No helicopter showed. Knowing that we were getting a ways away from the ship, we returned to the surface. The ship had hauled anchor, and was headed about 45 degrees off our course, so we discussed it and I freed the Mk-13 flare. This flare, when ignited, has a day end and a night end. The night end can been seen from well over a mile away at night, and the day end lets go of a bright, dense orange smoke for about twenty seconds. As the signal appeared, the ship swung around and headed for us. We got along side of the ship, and were given a rope to help us climb back in. We had a devil of a time getting in, as with the shallow draft and our heavy scuba tanks, we had nothing for our finned feet to push against. When we were finally aboard, the ship’s Captain was beside himself, talking a stream of Japanese which none of us could understand. We found out later he had told us, as best he could, not to dive until the tide changed. Then he looked, and we had already jumped in. He thought he had lost us.

That was the end of our diving for the helicopter. We docked, and the Captain insisted that we go to the officer’s club and he bought everyone all the drinks we could drink. Since I did not like alcohol, I was drinking Cokes. But after ten of fifteen Cokes, I thought my bladder would burst, and I was getting a bit hyper on caffeine. I switched to 7-Up’s. The others got pretty smashed. We were helicoptered back to Naha the next morning.

From Between Air and Water, the Memoir of a USAF Pararescueman, currently in draft stage.
Copyright 2013, John C. Ratliff

Please note that on E-Bay and other sites there are Mk 13 flares for sale; don't buy one, as these are in used and deteriorated condition and may be hazardous even to mail. There is a different flare which is available new. This is what I would get.


Datrex - IKAROS DAY/NIGHT SIGNAL detail

Please note that there is a person currently being prosecuted on federal charges which could land him in jail for pointing a laser pointer at jet airliners. I really don't think that the use of a laser, or laser pointer, is a good idea for search and rescue work. While you may be seen, you could compromise an entire air or helicopter crew by its use.
Portland man charged with aiming laser pointer at incoming planes | Local & Regional | KATU.com - Portland News, Sports, Traffic Weather and Breaking News - Portland, Oregon

SeaRat

 

[drbill]

Thanks John for your informed opinion. I wouldn't carry a laser in the water for any reason.

 

[John C. Ratliff]

One other piece of equipment we routinely used to locate divers and Pararescuemen (PJs) in the water is a waterproof strobe. In the 1970s it was known as the "Night Strobe Light SDU-5E..." and we had to check before jumping that it was "...attached and operational..." That strobe doesn't look to be currently available, but newer ones are there.
http://www.acrartex.com/products/b/marine/catalog/rescue-and-distress-lights

I know from my jumpmastering in the USAF that these strobes can be readily seen from the air at several miles distance at night. They are omni-directional (meaning that the intense strobe light goes out in all directions) and it is white light, not laser light.

However, there is now an even better solution, and that is an emergency locator beacon. I have never used these products, and have no hand in the commercial process. But they are available and should be considered if you are in a situation where they may be needed. Here is the website I found on a cursory search:
http://www.acrartex.com

There are probably other providers too, so take a look. But these are all better than a green laser, which cannot be seen unless it is pointed directly at someone, or illuminates a cloud or spray droplets (they were lucky those conditions existed).

SeaRat

 

[DandyDon]

One other piece of equipment we routinely used to locate divers and Pararescuemen (PJs) in the water is a waterproof strobe. In the 1970s it was known as the "Night Strobe Light SDU-5E..." and we had to check before jumping that it was "...attached and operational..." That strobe doesn't look to be currently available, but newer ones are there.
Rescue Lights | ACR ARTEX

I know from my jumpmastering in the USAF that these strobes can be readily seen from the air at several miles distance at night. They are omni-directional (meaning that the intense strobe light goes out in all directions) and it is white light, not laser light.

However, there is now an even better solution, and that is an emergency locator beacon. I have never used these products, and have no hand in the commercial process. But they are available and should be considered if you are in a situation where they may be needed. Here is the website I found on a cursory search:
ACR and Artex Products - The Science of Survival | ACR ARTEX

There are probably other providers too, so take a look. But these are all better than a green laser, which cannot be seen unless it is pointed directly at someone, or illuminates a cloud or spray droplets (they were lucky those conditions existed).

SeaRat

Yeah, a strobe would be a much better idea, and the PLB is great. I carry mine everywhere, but did dive it last trip...!

Bad idea, too great a risk of going wrong. PLB would be best.

The last thing I want to do is blind the pilot searching for me.

I dived with mine last trip. No problem and very reassuring when I surfaced alone away from all boats, but didn't get to the point of using it. Still, a nice idea. They can really home in on you with as PLB.

I got mine primarily for inland adventures, like the ones you see on the news every day about lost hikers, wrong wilderness roads, etc. $200 after rebate, floats, waterproof on the surface, good for 5 years, and if you ever have to use it - they replace it for free. Makes me wonder why we don't all have one? Dive canister was extra.

 

[knotical]

...Green laser pointers are usually a Class IIIA laser device, ... These lasers are required to have a warning label attached, and this one does not have it...

For the one Chugwhump mentioned, if you go to the website and click on “Get Price”, you can find the following info:

FDA Safety Class - IIIa
ANSI Safety Class - 3R

---------- Post added November 4th, 2013 at 01:05 PM ----------

As for danger to pilots, it would take a pretty steady hand to aim and hold a laser on a moving cockpit, let alone a pilot's eye. I suspect the prohibitions are pretty conservative and/or primarily directed toward more powerful lasers.

 

[Dr. Lecter]

My understanding is that laser dazzle is mainly a threat to pilots who are executing a landing. I doubt very much that even a good hit to the eyes during normal flight would pose a threat to the aircraft.

 

[John C. Ratliff]

For the one Chugwhump mentioned, if you go to the website and click on “Get Price”, you can find the following info:

FDA Safety Class - IIIa
ANSI Safety Class - 3R

---------- Post added November 4th, 2013 at 01:05 PM ----------

As for danger to pilots, it would take a pretty steady hand to aim and hold a laser on a moving cockpit, let alone a pilot's eye. I suspect the prohibitions are pretty conservative and/or primarily directed toward more powerful lasers.

knotical,

The beam diverges with distance. It is not so difficult to illuminate an entire cockpit with a beam at say 2 miles (the stated range).

Dr. Lecter,

It is probable that there would be no retinal injury from the beam. Here's some technical information:

Here are the technical specs for this laser:

Design & Operation
The SCUBA-1 green laser pointer illuminates particulates in the water to project a brilliant, easily seen laser beam and dot. This innovative underwater green laser pointer is salt water proof to 200 feet. Interact with marine life; use to signal your dive partners; point out marine life and objects of interest hundreds of feet away depending on light and water conditions; interact with marine life without disturbing the natural food chain. Draw marine life out of coves for underwater viewing and photography ( many fish species will follow the beam ). Can be used on land as well; at the dock, port or marina.

The SCUBA-1 is constructed of anodized aircraft grade aluminum; features constant on/off twist activation; includes a free wrist lanyard; and ships with a small bottle of oil to keep environmental o-rings soft and pliant. Power supply - 2 pcs AA batteries (included) Laser activates when cap is fully screwed on - back off end cap 1/2 turn to deactivate.
Length 7.60 in. x Diameter 0.94 in. ( 192 mm x 24 mm )
Wavelength (Color) - 532 nm (Emerald Green)
Output Power - 3.0 ~ 5.0 mW
Diode Operating Life - 3,000 to 5,000 hours
Diode Circuit Type - Computerized APC
Beam Diameter at Source - 1.1 mm
Output Mode - Constant Wave
Range ( Night ) - 2 Miles
FDA Safety Class - IIIa
ANSI Safety Class - 3R
Warranty - 1 Year
http://www.z-bolt.com/green-laser-pointers/special-function/waterproof-laser-pointer-scuba-1.html

So this laser is being marketed to scuba divers! For classification purposes, the power output (3-5 milliWatts) and the wavelength (532 nanometers) are the critical parameters. A Class 3a laser is defined in ANSI Z136.1--2007 as:

3.3.2 Classes 2 and 2M Visible Lasers and Laser Systems. Classes 2 and 2M lasers and laser systems are visible (0.4 to 0.7 um) CW and repetitive-pulse lasers and laser systems which can emit accessible radiant energy exceeding the appropriate Class 1 AEL for the maximum duration inherent in the design or intended use of laser or laser system, but not exceeding the Class 1 AEL for any applicable pulse (emission) duration < 0.25 s and not exceeding the accessible average radiant power of 1 mW. Class 2M lasers and laser systems pose the same ocular hazards to the unaided eye as Class 2, but are potentially hazardous when viewed with optical aids.

3.3.3.1 Class 3R lasers and laser systems include lasers and laser systems which have an accessible output...less than 5 times the Class 2 AESL for wavelengths between 0.4 and 0.7 um (micrometers).

Class 3R actually originates from IEC Classifications.

*Note on nomenclature. 'M' in Class 1M and Class 2M is derived from Magnifying optical viewing instruments. 'R' in Class 3R is derived from Reduced or Relaxed requirements: reduced requirements both for the manufacturer (e.g. no key switch and interlock connector required) and for the user (usually no eye protection necessary)...

A Class 3a laser at 5 micro watts is right on the border of being classified as hazardous; the classifications of Class IIIa, 3a and 3R (using FDA, ANSI Z136.1, and IEC 60825-1 standards) are considered in a "transitional (threshold) zone." according to training I received from R. Timothy Hitchcock, CIH, CLSO, LightRay Consulting, in 2004. I think the newer ANSI Z136.1 may have incorporated the IEC designations too, but am not sure at this point.

Concerning the dazzle situation, according to my sources this can be very startling.

*6.2 Additional beam hazards
6.2.1 Dazzle

It is possible that visible-beam lasers can cause indirect harm even where the exposure level is below the MPE.** This is because of their ability to startle or dazzle any unsuspecting person who is exposed to the laser beam, heather deliberately or not. Protection from direct harm from any laser in Class 2 or 2M is normally provided by natural aversion responses. Even so, the exposed individual can be distracted or startled by a sudden, unexpected exposure. This can also occur from exposure to a visible-beam Class I laser, and from visible-beam lasers of higher class even beyond the NOHD*** where exposure might otherwise be considered safe. Such exposure can have serious consequences if the person is performing a safety-critical task (such as driving). It can also cause disturbing after-images in the individual's eyes, and may generate fear if the person believes that their eyes might have been harmed by the exposure.

Even low-power visible-beam lasers should therefore be used with care. Where there is a risk that people unconnected with the laser work and unaware that lasers are in use may be accidentally exposed, even at levels below the MPE, the use of screens, curtains or other suitable enclosures should be considered, or physical limits set on the range of beam movements that are possible.

Visible-beam lasers should never be used to deliberately surprise or alarm other people. The US standard for safe laser use...defines criteria for dazzle effects.

Please note the third definition below. It refers to use of magnifying instruments. If on a boat divers are missing, and the captain is looking for them, would he possibly be using binoculars or a telescope? If so, then all bets are off for the classification of the laser.

SeaRat

*Henderson, Roy and Karl Schulmeister, Laser Safety, Institute of Physics Publishing, Bristol and Philadelphia, 2004, pages 354-355.
**Accessible emission limit (AEL). The maximum accessible emission level permitted within a particular laser hazard class.
MPE = Maximum Permissible Limit, "The level of laser radiation to which an unprotected person may be exposed without adverse biological changes to the eye or skin." from ANSI Z136.1-2007.
***NOHD--nominal ocular hazard distance, the distance from a laser over which the MPE for the eye may be exceeded, provided that no magnifying viewing instruments are used.* (IBID, page 440)

 

[ams511]

I remember reading a few years back that aircraft were to be outfitted with early warning receivers to warn the pilots of an attack. A laser may trip that system, as a beam riding missile could be kept on target on a plane taking off or landing.

 

[PeterNBiddle]

I remember reading a few years back that aircraft were to be outfitted with early warning receivers to warn the pilots of an attack. A laser may trip that system, as a beam riding missile could be kept on target on a plane taking off or landing.

Civilian jets don't carry missile counter measures, do they?

How in the world would knowing someone has locked a Stinger into you help a 737 pilot? So he/she can dodge the missile?