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

[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.

I’m not sure about cycling the distress alert signal to ON for 20 minutes & OFF for 1 hour for MRG / PLB would extend their battery life to 3 times. You would basically turning them on / off 18-19 times in 24 hours. Every time you activate them, it takes more energy to start up the transmission & obtaining a GPS fix than during the steady transmission. Like an airplane, it takes more energy during take off than during cruising. You gave better mileage per gallon driving in highway than in city traffic.

To activate PLB1, after pressing the ON key, the green LED light will flash once during 5 seconds while GPS is turned on and obtaining a fix. Once the fix is obtained, the green LED will flash quickly 3 times. Afterwards repeating alert sequence of 406 & 121.5 MHz transmission begins. I would imagine by repeating this PLB1 activation 18-19 times a day would not last my PLB1 battery life to 3 days.

Besides wasting the activation energy, you would be alerting the SAR Rescue Center every time you activate the PLB and the repetition of 18-19 activations / day might be received as false alert. Apparently PLB false alert transmission is pretty common to the point of NOAA posting a webpage to educate PLB owners on how to avoid sending false alert, NOAA - Search and Rescue Satellite Aided Tracking - Prevent False Alerts

“The following are some suggestions on how you (yes, you) can prevent false alerts. By doing so, you will increase the effectiveness of the very system your life may someday rely on! We can not stress the importance of this enough. Responding to the false alerts can cause large delays in responding to real emergencies. Unnecessary deployments also put the lives of search and rescue personnel at risk. Although Cospas-Sarsat is a high-tech, automated system, large volumes of false alerts can cost valuable minutes to people in real distress. Every little bit does help! So please, read the recommendations below and follow them. Above all, use common sense.

FOR PLB’s:

• Always test your PLB in strict accordance with manufacturers’ recommendations. Most PLB activation switches have a test position. This test position allows the entire unit (electronics, battery and antenna) to be tested without generating a false alert.

• Ensure that your beacon is registered with NOAA. This does nothing to reduce false alert rates, but does have a dramatic effect on the impact of a false alert. If the PLB is properly registered, the situation will be resolved with a phone call most of the time. It will also help speed rescue in an actual distress. It's free, easy, and it's the law, so please register all of your beacons.

• Maintain your PLB. Ensure that the batteries are within their expiration date and that all manufacturer recommendations are followed.”

MRG battery life may not be a problem. According to Ryan of Nautilus Lifeline, the batteriy should last quite a bit longer than one day. Assuming a full battery, the Nautilus GPS can continue transmitting the distress signal up to 80-90 hours. I do have spare CR123 Lithium batteries in my waterproof safety kit pouch anyway.

 

[Dan]

I just got the Divesoft Fluorescein Dye Marker. It’s in pretty small plastic tube with sealed cap about the size of coke bottle cap, small enough to fit in my BCD pocket with the rest of my safety kit. Below is what it looks like, relative to PLB1 & MRG. I’m good to go now, I think

 

[CWK]

MRG battery life may not be a problem. According to Ryan of Nautilus Lifeline, the batteriy should last quite a bit longer than one day. Assuming a full battery, the Nautilus GPS can continue transmitting the distress signal up to 80-90 hours. I do have spare CR123 Lithium batteries in my waterproof safety kit pouch anyway.

This is great info. It is certainly a game changer that, in my view, makes the MRG more valuable.

I’m not sure about cycling the distress alert signal to ON for 20 minutes & OFF for 1 hour for MRG / PLB would extend their battery life to 3 times. You would basically turning them on / off 18-19 times in 24 hours. Every time you activate them, it takes more energy to start up the transmission & obtaining a GPS fix than during the steady transmission. Like an airplane, it takes more energy during take off than during cruising. You gave better mileage per gallon driving in highway than in city traffic.

To activate PLB1, after pressing the ON key, the green LED light will flash once during 5 seconds while GPS is turned on and obtaining a fix. Once the fix is obtained, the green LED will flash quickly 3 times. Afterwards repeating alert sequence of 406 & 121.5 MHz transmission begins. I would imagine by repeating this PLB1 activation 18-19 times a day would not last my PLB1 battery life to 3 days.

OK. So in a really remote 3rd world dive location I could conserve the PLB into day 2 by switching the PLB on for 20 mins once every 6Hrs until the 24Hr mark, thereafter I'd leave it on until rescue or the battery runs out.

I should not matter if the battery of the PLB runs out. In this scenario, I would be using the PLB to tell SAR my drift direction and speed. This would lead them into my MRG broadcast range and the MRG has a trinsmission window of 80 to 90Hrs. If the PLB is dead by the time they get there, SAR can still get my GPS psoition from the MRG.

Apparently PLB false alert transmission is pretty common to the point of NOAA posting a webpage to educate PLB owners on how to avoid sending false alert, NOAA - Search and Rescue Satellite Aided Tracking - Prevent False Alerts

Local SAR will know who I am and that I missing because the dive operation, which has my ID and emergency contact information, would have initiated contact with SAR. When NOAA detects the PLB activation, they will contact my national PLB registration authority, which has my identity details that will be passed on to local SAR. Local SAR should be able to ascertain that the two alerts through different routes relate to the same person and know that it is not a false alert. With the PLB, NOAA has to be in continual contact with local SAR to give them updated GPS data. As such NOAA should be informed by local SAR that it is a genuine alert. They may not know why I am switching the unit on and off but the reasoning can be given after rescue.

I dive locations where SAR should arrive within 24Hrs most of the time - probably 90% of the time. Let me refine some probability estimates for such dive locations.

Probability that SAR will find me when the PLB is activated: 100%
SAR will have my GPS position accurate to within 1.5m. They do not have to search, only to pick me up.

Probability that SAR will find me when the MRG is activated: 99.999%
According to Nautilus, "a man overboard distress message will be broadcast to all AIS equipped ships up to 34 miles away". Nautilus claims a broadcast range of 34 miles. That is to say that the broadcast footprint is a circle with a radius of 34 miles. Given MRGs transmission window of 80 to 90Hrs, SAR, which should have AIS, would almost certainly enter the broadcast footprint and will pick up my GPS coordinates. I estimate a probability of 0.001% that they fail to enter the broadcast footprint during the MRGs transmission window of 80 to 90Hrs.

Probability that a diver experiences boat seperation: 1%
I maintain the assumption that 1 out of every 100 divers will experience boat seperation.

Probability that SAR will be called in a boat seperation incident: 20%
Most boat seperation incidents are resolved before SAR is called. I estimate that the MRG, SMB, Dive Alert, whistle, signal mirror, and torch whould resolve the situation before SAR is called in 4 out of every 5 incidents. Therefore, the probability that SAR will be called once there is a boat seperation incident is 20%

Probability that a diver will be involved in a boat seperation incident and SAR has to be called: 0.2%
1% x 20% = 0.2%.

Probability that my PLB fails when activitated: 1%
I intend to test my PLB once a year and change the battery or PLB once every 4 years. I don't think it should be higher.

Probability than my MRG fails when activated: 1%
I intend to change batteries once a year and test the MRG immediately after changing batteries. A MRG is not expensive, I could also get a new MRG every 4 years. I don't think the failure rate of my MRG should be higher.

Probability that I experience a boat seperation that results in a call to SAR, and both my PLB and MRG fail.
1% x 20% x 1% x 1% = 0.000002%.

What probability estimates are you assuming?

 

[CWK]

Assuming a full battery, the Nautilus GPS can continue transmitting the distress signal up to 80-90 hours. I do have spare CR123 Lithium batteries in my waterproof safety kit pouch anyway.

You are certainly prepared! With the spare batteries, you will have 160 to 190 hours. You will need a dry place in order to change the batteries. Perhaps a raft? Diver's Life Raft, 6' long, inflatable floor

 

[Jay]

Has anyone flown with Divesoft Fluorescein Dye Marker? (regularly?)

I really like the product but as I always fly & dive it seems that it might just bring me airport grief ...

 

[Dan]

Has anyone flown with Divesoft Fluorescein Dye Marker? (regularly?)

I really like the product but as I always fly & dive it seems that it might just bring me airport grief ...

It is classified as “Non hazardous” in section 14 (page 3) Transportation Information of http://www.kelloggmarine.com/msds/OLI-Orion Safety Products/Fluorescein Dye Marker.pdf

Some food processor use it as food coloring Fluorescein, Sodium Salt by Penta Manufacturing Company - Food, Beverage & Nutrition Have you seen some bright yellow scrambled eggs in hotel breakfast buffets?

And...... (drum rolls)...... IT FLOATS!

It’s sealed tightly and waterproof down to 100m (328’), which is way beyond my deepest dive (44m / 144’)

 

[Dan]

This is great info. It is certainly a game changer that, in my view, makes the MRG more valuable.


OK. So in a really remote 3rd world dive location I could conserve the PLB into day 2 by switching the PLB on for 20 mins once every 6Hrs until the 24Hr mark, thereafter I'd leave it on until rescue or the battery runs out.

I should not matter if the battery of the PLB runs out. In this scenario, I would be using the PLB to tell SAR my drift direction and speed. This would lead them into my MRG broadcast range and the MRG has a trinsmission window of 80 to 90Hrs. If the PLB is dead by the time they get there, SAR can still get my GPS psoition from the MRG.


Local SAR will know who I am and that I missing because the dive operation, which has my ID and emergency contact information, would have initiated contact with SAR. When NOAA detects the PLB activation, they will contact my national PLB registration authority, which has my identity details that will be passed on to local SAR. Local SAR should be able to ascertain that the two alerts through different routes relate to the same person and know that it is not a false alert. With the PLB, NOAA has to be in continual contact with local SAR to give them updated GPS data. As such NOAA should be informed by local SAR that it is a genuine alert. They may not know why I am switching the unit on and off but the reasoning can be given after rescue.

I dive locations where SAR should arrive within 24Hrs most of the time - probably 90% of the time. Let me refine some probability estimates for such dive locations.

Probability that SAR will find me when the PLB is activated: 100%
SAR will have my GPS position accurate to within 1.5m. They do not have to search, only to pick me up.

Probability that SAR will find me when the MRG is activated: 99.999%
According to Nautilus, "a man overboard distress message will be broadcast to all AIS equipped ships up to 34 miles away". Nautilus claims a broadcast range of 34 miles. That is to say that the broadcast footprint is a circle with a radius of 34 miles. Given MRGs transmission window of 80 to 90Hrs, SAR, which should have AIS, would almost certainly enter the broadcast footprint and will pick up my GPS coordinates. I estimate a probability of 0.001% that they fail to enter the broadcast footprint during the MRGs transmission window of 80 to 90Hrs.

Probability that a diver experiences boat seperation: 1%
I maintain the assumption that 1 out of every 100 divers will experience boat seperation.

Probability that SAR will be called in a boat seperation incident: 20%
Most boat seperation incidents are resolved before SAR is called. I estimate that the MRG, SMB, Dive Alert, whistle, signal mirror, and torch whould resolve the situation before SAR is called in 4 out of every 5 incidents. Therefore, the probability that SAR will be called once there is a boat seperation incident is 20%

Probability that a diver will be involved in a boat seperation incident and SAR has to be called: 0.2%
1% x 20% = 0.2%.

Probability that my PLB fails when activitated: 1%
I intend to test my PLB once a year and change the battery or PLB once every 4 years. I don't think it should be higher.

Probability than my MRG fails when activated: 1%
I intend to change batteries once a year and test the MRG immediately after changing batteries. A MRG is not expensive, I could also get a new MRG every 4 years. I don't think the failure rate of my MRG should be higher.

Probability that I experience a boat seperation that results in a call to SAR, and both my PLB and MRG fail.
1% x 20% x 1% x 1% = 0.000002%.

What probability estimates are you assuming?

I don’t do probability estimates. My thought is time is of the essence. The sooner I get rescued, the better my chance to be found alive.

I plan to turn on my MRG right after the boat fails to see my DSMB (within 30 minutes of surfacing). Will keep it ON at all time. Don’t want any boat to miss my alert signal.

Once no boat is seen in the horizon, then I’ll launch my PLB1. Having 1 watt VHF (30-300 MHz) for surface-surface SOS transmission by MRG & 5 watt 406 MHz surface-satellite SOS transmission by PLB1 for the first 24 hour will greatly increased my chances to be found alive.

After the PLB1 is dead, I’d still have the MRG to emit the VHF signal. Once it runs out of battery, then, I’ll replace the batteries with fresh ones. My BCD will be fully inflated to keep my head, chest & arms above water to do “dry-enough” battery change procedure above water surface.

 

[Dan]

You are certainly prepared! With the spare batteries, you will have 160 to 190 hours. You will need a dry place in order to change the batteries. Perhaps a raft? Diver's Life Raft, 6' long, inflatable floor

For me that life raft will be way too bulky to carry around in warm-water diving. It may be a good idea to have it if I dive in remote cold (<60F / 15C) place, which is highly unlikely I’d do.

 

[MargaritaMike]

You are certainly prepared! With the spare batteries, you will have 160 to 190 hours. You will need a dry place in order to change the batteries. Perhaps a raft? Diver's Life Raft, 6' long, inflatable floor

I looked for this in the states and couldn't find it. This is something that I could add to my Christmas tree as well as keep me dry while waiting for my rescuers. I could keep my dehydrated water packets with it.

Cheers -

 

[Dogbowl]

For me that life raft will be way too bulky to carry around in warm-water diving. It may be a good idea to have it if I dive in remote cold (<60F / 15C) place, which is highly unlikely I’d do.

Looks like if you had a Halcyon bpw, and matching MC storage pac attached to the backplate, this raft can fit neatly in there.

BC Storage Pak

PERSONAL LIFEBOAT
Modeled after the Air Force and Navy Single Man Life Boat, the DLR provides unprecedented safety at sea. The DLR can be integrated into the MC system, hidden neatly behind the diver's back in the MC Storage Pak, or folded into an optional external pouch. Spend the night, salvage rainwater, and broaden the "visibility dot" on the sea literally ten-fold with this six-foot, 300+ pound inflatable boat. The device can be inflated orally or with your BC hose.

I do suppose they mean 300+ pounds of lift and not that it weighs 300+ pounds!

Honestly I think it’s a discontinued product as I couldn’t find it on the Halcyon website.