Best signaling devices from the searcher’s point of view - update

[CWK]

I have quite a few signalling devices but certainly less than @Dan_T. I now don't really think about getting more signalling devices but do think along different lines:

1. I think of upgrading what I have. As an example, my existing SMB will be replaced with a SOLAS SMB or a radar reflecting SMB. And, instead of eventually replacing the battery in my existing PLB that is rated for 24+Hrs, I'd be looking for a PLB that is rated for 36Hrs.

2. I also think of ways to deploy my signalling devices more effectively. My two radio beacons have operational limits of 24+Hrs for continuous transmission. To me, there is no need for continuous transmission, so I'm thinking of how best to deploy them intermittantly in order to extend their deployment window beyond 24Hrs. For the MRG, I'm thinking of activating it immediately for 20mins than switching it off for 1Hr and repeating. Assuming that I am drifting at 5 nautical miles per hour, I will have sequential MRG circular broadcast footprints that are 5 nautical miles apart at the centre and should be just as effective as having it broadcast continuously. However, I'd be extending transmission from 24Hrs to 96Hrs. I'm thinking along similar lines (intermittant transmission) for the PLB. SAR should have been alerted by the boat or resort that I'd diving with as part of the lost diver protocol, so there should be no need to activate the PLB immediately in order to tell SAR that I am lost at sea. I'd probably activate the PLB after 6Hrs, which immediate extends its transmission window by 6Hrs from the start of the situation. SAR will probably not get to me within 6Hrs anyway if I am are diving remote 3rd world countries. Once the PLB is activated, SAR will have my present coordinates as well as my initial coordinates from the dive boat/resort and can plot a reasonably accurate intercept for my drift direction and speed. Activating the PLB for 20mins then deactivating it for the next hour extends its useful life to 96Hrs, which in addition to 6Hrs for the initial delay in transmission, gives a total of 102Hrs. By activating the PLB intermittantly (20mins on then 60mins off), SAR has a continual plot of my drift to help them narrow the search area. These radio beacons give GPS coordinates, which should be highly accurate so SAR should get to me once I have started activating them.

3. I think of how to survive longer should SAR be a little slow. By using my two radio beacons intermittantly, I can extend the useful transmission window to in excess of 96Hrs. The survival guideline is 3 days(72Hrs) without water. This is the limiting factor that I have to address. Given limited carrying capacity, I'd prioritise some water over more signalling devices.

 

[BertStevens]

Not allowed by FAA. I talked to the seller over the phone. He said it is explosive product and it is therefore forbidden to fly with it.

Is this for the flares or dye?

 

[Dan]

Is this for the flares or dye?

Oops! My bad. I was referring to the flare.

The dye should be fine for air travel. It’s dry powder, contained in a plastic (not glass) tube & has high ignition temperature of > 167F (75C).

 

[Dogbowl]

Oops! My bad. I was referring to the flare.

The dye should be fine for air travel. It’s dry powder, contained in a plastic (not glass) tube & has high ignition temperature of > 167F (75C).

No concerns about carrying a coloured dry powder into a foreign country? I’m thinking it might be mistaken for drugs? I suppose they could test it if they have that drug testing machine onsite.

 

[Dan]

No concerns about carrying a coloured dry powder into a foreign country? I’m thinking it might be mistaken for drugs? I suppose they could test it if they have that drug testing machine onsite.

I print its Safety Data Sheets, invoice receipt and carry it together with other safety device manuals (for PLB1 & MRG).

 

[Dan]

I have quite a few signalling devices but certainly less than @Dan_T. I now don't really think about getting more signalling devices but do think along different lines:

1. I think of upgrading what I have. As an example, my existing SMB will be replaced with a SOLAS SMB or a radar reflecting SMB. And, instead of eventually replacing the battery in my existing PLB that is rated for 24+Hrs, I'd be looking for a PLB that is rated for 36Hrs.

2. I also think of ways to deploy my signalling devices more effectively. My two radio beacons have operational limits of 24+Hrs for continuous transmission. To me, there is no need for continuous transmission, so I'm thinking of how best to deploy them intermittantly in order to extend their deployment window beyond 24Hrs. For the MRG, I'm thinking of activating it immediately for 20mins than switching it off for 1Hr and repeating. Assuming that I am drifting at 5 nautical miles per hour, I will have sequential MRG circular broadcast footprints that are 5 nautical miles apart at the centre and should be just as effective as having it broadcast continuously. However, I'd be extending transmission from 24Hrs to 96Hrs. I'm thinking along similar lines (intermittant transmission) for the PLB. SAR should have been alerted by the boat or resort that I'd diving with as part of the lost diver protocol, so there should be no need to activate the PLB immediately in order to tell SAR that I am lost at sea. I'd probably activate the PLB after 6Hrs, which immediate extends its transmission window by 6Hrs from the start of the situation. SAR will probably not get to me within 6Hrs anyway if I am are diving remote 3rd world countries. Once the PLB is activated, SAR will have my present coordinates as well as my initial coordinates from the dive boat/resort and can plot a reasonably accurate intercept for my drift direction and speed. Activating the PLB for 20mins then deactivating it for the next hour extends its useful life to 96Hrs, which in addition to 6Hrs for the initial delay in transmission, gives a total of 102Hrs. By activating the PLB intermittantly (20mins on then 60mins off), SAR has a continual plot of my drift to help them narrow the search area. These radio beacons give GPS coordinates, which should be highly accurate so SAR should get to me once I have started activating them.

3. I think of how to survive longer should SAR be a little slow. By using my two radio beacons intermittantly, I can extend the useful transmission window to in excess of 96Hrs. The survival guideline is 3 days(72Hrs) without water. This is the limiting factor that I have to address. Given limited carrying capacity, I'd prioritise some water over more signalling devices.

It’ll be definitely a sad situation when you see SAR boat / airplane, but they don’t see you and you PLB / MRG run out of batteries.

Do you test your PLB & MRG during a checkout dive / first day of a week-long dive trip?

 

[BertStevens]

I read some where about the dye will be diffuse & fade away about 30 minutes. That’s kind of short live of signaling device don’t you think?

Not knowing how long it lasts has been bugging me. “I read somewhere...” isn’t enough (no slight intended) I just ran across this about the OMS dye on LeisurePro’s website.

Chemical Sea Dye Markers, come in tubes or vials that contain a highly visible fluorescent, “dye slick” that lasts for 15- 30 minutes and enables aircraft to quickly locate the lost diver. This “slick” can be seen for up to a mile or more and is a great passive method of signaling.

Current and wind action affect the duration of the dye slick and in strong seas this will get washed away in minutes. The non fluorescent dyes are of no use in the night time as they cannot be spotted In the dark.​

 

[Dan]

You can make it last longer by dunk it a little bit at a time as mentioned by @Navy OnStar in his post #1 of this thread Best signalling equipment from the searchers point of view

“#3 Sea DYE Marker
PROS: Cheap. Passive marker. If you are tired/incapacitated you don't have to do much to deploy.
CONS: Choppy/strong current/rough waters tend to dissapate quickly. Useless at night
If you dunk it to make a "Dye slick" and then put away until slick goes away and repeat - it'll last longer”

 

[Dan]

Another Dye Marker source: Survival Dye Marker

 

[CWK]

Do you test your PLB & MRG during a checkout dive / first day of a week-long dive trip?

Batteries are cheap. I intend to change batteries for my MRG once a year. The MRG will be tested each time the batteries are changed. My PLB will be tested once a year and either the battery or the PLB will be changed every 4 years. This is well in advance of PLB battery replacement cycles, which should typically be 6 years. PLBs are not that expensive.

It’ll be definitely a sad situation when you see SAR boat / airplane, but they don’t see you and you PLB / MRG run out of batteries.

I try and think in terms of probabilities. In terms of remote 3rd world dive locations, the probability I assign to SAR arriving on the scene within XHrs is as follows:
- within 24Hrs: 5%
- within 48Hrs: 75%
- within 72Hrs: 99.9%
- within 96Hrs: 99.999%
This probability distribution says that I expext SAR to arriive between 24 and 72hrs (2 to 3 days) for remote 3rd world dive locations. I plan to conserve my MRG and PLB batteries to 96Hrs (4 days) as a contingency in case the batteries are weaker than expected or the batteries are depleated faster than expected.

I also think of other probabilities. I'll put some below.

Probability that any diver will experience boat seperation in his/her lifetime: 1%
I expect 1 out of 100 divers to experience some form of boat seeperation in their lifetime. Most of these events should be resolved before SAR is called upon.

Probability that my MRG will fail when activated: 1%
I will be changing the batteries every 12 months and will test the unit after changing batteries. I don't really expect it to fail within a year of battery change even though that possibility exists.

Probability that my PLB will fail when activated: 1%
I will test my PLB yearly and change the battery or PLB every 4 years. This is well ahead of PLB battery replacement cycles. I don't really expect my PLB to fail when activated although that possibility exists.

Probablity that I will experience a boat seperation incident and failure of both my MRG and PLB: 0.0001%
1% x 1% x 1% = 0.0001% which should be 1 in 1,000,000. I think that a successful SAR when one has a working PLB is probably 99.999%. Since SAR assets probably have AIS, a successful SAR when one has a working MRG may be 99% as SAR has only to get within the MRGs broadcast range to find me. I also do quite a number of LOBs and can select LOBs based on the availability of AIS, therefore a MRG may be more effective than a PLB when I am on a LOB.

Feel free to assign different probabilities to various events as you think fit. Let me know where your expected probabilities differ significantly from mine.

I am concerned about boat seperation and maintain an interest in signalling devices. However, I'm pretty comfortable with my choiice of signalling devices which are:
- SMB
- Dive Alert (and whistle)
- Torch with SOS mode (x2 on a night dive)
- Signal mirror
- MRG
- PLB

At times, there are additional redundancies. My only regular dive buddy, with whom I go on trips 3 or 4 times a year (I do more than 12 a year) has a MRG and will be getting a PLB soon. This is in addition to her air horn, SMB and torch. So between the pair of us, there will be more than sufficient signalling devices.

I feel that I have acquired sufficient signalling devices. There will always be that one chance in a million, but that is also true of walking across the street.