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

[Dan]

A good Tek Tip from Dive Gear Express, Nautilus Marine Rescue GPS on the original (old model with 2-way VHF radio) & new Nautilus Lifeline (without 2-way VHF radio and what I refer to it as MRG):

“The original Nautilus Lifeline Safety VHF Radio device is a battery-operated waterproof marine VHF radio that can be carried by divers and supports two-way voice communication. As part of the marine VHF radio functionality, the original Lifeline also includes the older Digital Selective Calling (DSC) feature. DSC is a standard for sending pre-defined digital messages as part of the Global Maritime Distress Safety System. When sending a distress signal, the DSC device must include the ship's MMSI number. The Safety VHF Radio requires a radio operators certificate for non-emergency use and also requires an MMSI registration in order to enable the DSC feature. The device also needs to have the battery recharged via a USB cable every few months. The Lifeline Safety VHF Radio has been discontinued and is no longer available from the manufacturer.

The new Nautilius Lifeline Rescue GPS is a compact battery-operated waterproof marine emergency distress radio beacon that can be carried by divers and is depth rated to { 425 feet | 130 meters } with cap closed. It also supports the more recent Automatic Identification System (AIS) signalling functionally which includes your GPS coordinates and a Maritime Identification Digits (MID) user number that comes pre-programmed at the factory. The Rescue GPS device does not require licenses or registrations. The low-maintenance Rescue GPS is very small and the standard two CR123 batteries need only be replaced every five years.

Don't confuse either of the Nautilus Lifeline products with an EPIRB. The much larger EPIRB beacons are satellite transmitters with global reach and monitoring. The Lifeline devices are line-of-sight VHF radios that rely upon direct communication with marine VHF radios on vessels and shore base-stations up to { 34 mi | 55 km } distant.”

 

[CWK]

The Lifeline devices are line-of-sight VHF radios that rely upon direct communication with marine VHF radios on vessels and shore base-stations up to { 34 mi | 55 km } distant.”

They may be assuming a shore base-station situated on a hill. From Wikipedia (Horizon - Wikipedia):

• For an observer standing on the ground with h = 1.70 metres (5 ft 7 in), the horizon is at a distance of 4.7 kilometres (2.9 mi).
• For an observer standing on the ground with h = 2 metres (6 ft 7 in), the horizon is at a distance of 5 kilometres (3.1 mi).
• For an observer standing on a hill or tower of 100 metres (330 ft) in height, the horizon is at a distance of 36 kilometres (22 mi).

 

[Dan]

They may be assuming a shore base-station situated on a hill. From Wikipedia (Horizon - Wikipedia):

• For an observer standing on the ground with h = 1.70 metres (5 ft 7 in), the horizon is at a distance of 4.7 kilometres (2.9 mi).
• For an observer standing on the ground with h = 2 metres (6 ft 7 in), the horizon is at a distance of 5 kilometres (3.1 mi).
• For an observer standing on a hill or tower of 100 metres (330 ft) in height, the horizon is at a distance of 36 kilometres (22 mi).

I think so. I wouldn’t rely on the MRG signal being received beyond 3 miles where the liveaboard is just a speck in horizon with MRG’s antenna sticking up may be about 2 feet (60 cm) above the sea level with my hand, holding the MRG, raised straight up above the water.

That’s why I have the PLB1 as my alerting device of the last resort if I were to see the boat disappeared into the horizon.

 

[jjardin]

5’ plastic coated coiled wire & clips on both ends of the coiled wire

View attachment 452888

I think I would like to be able to cut free of my reef hook if needed. That being said I have never had a problem unhooking.

 

[Dan]

I think I would like to be able to cut free of my reef hook if needed. That being said I have never had a problem unhooking.

That’s the beauty of having such clips. If you can’t reach out to the hook, you just unclip it off your chest D-ring, just like the picture, below. Simple!

 

[Rred]

CWK-
"I would always expect local SAR to show up."
In the best case, they will show up.
" The probability of the international Compas-Sarsat guys showing up to fish you out of the water is probably about 0.0000000000000000000001%"
Actually it is fully "zero". The COSPAS-SARSAT system does not deploy any SAR assets of their own. They verify the signal and pass the information along to the correct authorities, whether that is the Indonesian Coast Guard, or the New Mexico State Police.

"If you use a PLB no local boaters or commercial traffic will be alerted. If you use the MRG, local boaters and commercial traffic with AIS enabled marine radios will be alerted."
MRG is not a conventional boating jargon here in the US, so I'm not sure what you mean.
But here, the USCG uses the international AMVER system to alert and direct commercial vessels to respond, and a "Pan Pan" warning notification would go out if the area was in VHF range of a base. So, local authorities and vessels WILL be alerted as part of the response. If a commercial vessel (typically on the high seas) can be reached through AMVER, there is no need to dispatch air assets or others.

On the other hand, if you use AIS/DSC, you are relying on local traffic. Recreational sailors who often have their VHF off, and sometimes even fishermen or dive boats, who don't want to let anyone else know exactly where their "special" spot is. But the advantage is that IF someone is using AIS/DSC nearby, you can reach closer local help. "IF".

On GPS and electronic charting...again, all well and good in theory. Not the same in practice, especially in parts of the world that may have last been surveyed 150 years ago, where the basis is incorrect or the GPS "World Map" needs a transformation applied because the earth is not a perfect sphere. Last time I looked, the NOAA charts outside of NY Harbor had some positions 1/2 mile off the GPS co-ordinates given for them. And actually, 15 years ago, folks trying to use GPS in NYC (including DeLorme and Garmin and everyone else in the "new" auto nav business) were having fits because NYC's mapping is all based on an old Dutch colonial era base map--which is very different from GPS and the grids used today.

GPS needs to be taken with a big grain of salt, as everyone who has driven off a ferry landing will attest. Even when it is properly used? I know someone who ran aground near Miami about three years ago. Sent his request for a tow in via one of the private vendors (InReach, Spot, that type). Except...apparently they gave the GPS coordinates to the tow company, who called back to say "There's no one here". There are many different ways to express latitude and longitude, whether it is DDD.MM.SS or DDD.MM.MM or DDD.DDDDD, which is the formal ISO standard, strictly degrees and decimals. If the chain of response includes anyone who doesn't know and confirm the formats? Yeah, not so good. So, using one of the third-party solutions has pros and cons as well.

The systems all have weak points, as well as complexities that the general public just isn't bothered with. But if you are really trying to pre-plan for rescue...they all should be considered. If I wasn't Real Damn Sure there was lots of local *commercial* boat traffic equipped with AIS? I think I'd rather stick to the COSPAS-SARSAT EPIRB/PLB system. No one does it better.

 

[Dan]

CWK-
"I would always expect local SAR to show up."
In the best case, they will show up.
" The probability of the international Compas-Sarsat guys showing up to fish you out of the water is probably about 0.0000000000000000000001%"
Actually it is fully "zero". The COSPAS-SARSAT system does not deploy any SAR assets of their own. They verify the signal and pass the information along to the correct authorities, whether that is the Indonesian Coast Guard, or the New Mexico State Police.

"If you use a PLB no local boaters or commercial traffic will be alerted. If you use the MRG, local boaters and commercial traffic with AIS enabled marine radios will be alerted."
MRG is not a conventional boating jargon here in the US, so I'm not sure what you mean.
But here, the USCG uses the international AMVER system to alert and direct commercial vessels to respond, and a "Pan Pan" warning notification would go out if the area was in VHF range of a base. So, local authorities and vessels WILL be alerted as part of the response. If a commercial vessel (typically on the high seas) can be reached through AMVER, there is no need to dispatch air assets or others.

On the other hand, if you use AIS/DSC, you are relying on local traffic. Recreational sailors who often have their VHF off, and sometimes even fishermen or dive boats, who don't want to let anyone else know exactly where their "special" spot is. But the advantage is that IF someone is using AIS/DSC nearby, you can reach closer local help. "IF".

On GPS and electronic charting...again, all well and good in theory. Not the same in practice, especially in parts of the world that may have last been surveyed 150 years ago, where the basis is incorrect or the GPS "World Map" needs a transformation applied because the earth is not a perfect sphere. Last time I looked, the NOAA charts outside of NY Harbor had some positions 1/2 mile off the GPS co-ordinates given for them. And actually, 15 years ago, folks trying to use GPS in NYC (including DeLorme and Garmin and everyone else in the "new" auto nav business) were having fits because NYC's mapping is all based on an old Dutch colonial era base map--which is very different from GPS and the grids used today.

GPS needs to be taken with a big grain of salt, as everyone who has driven off a ferry landing will attest. Even when it is properly used? I know someone who ran aground near Miami about three years ago. Sent his request for a tow in via one of the private vendors (InReach, Spot, that type). Except...apparently they gave the GPS coordinates to the tow company, who called back to say "There's no one here". There are many different ways to express latitude and longitude, whether it is DDD.MM.SS or DDD.MM.MM or DDD.DDDDD, which is the formal ISO standard, strictly degrees and decimals. If the chain of response includes anyone who doesn't know and confirm the formats? Yeah, not so good. So, using one of the third-party solutions has pros and cons as well.

The systems all have weak points, as well as complexities that the general public just isn't bothered with. But if you are really trying to pre-plan for rescue...they all should be considered. If I wasn't Real Damn Sure there was lots of local *commercial* boat traffic equipped with AIS? I think I'd rather stick to the COSPAS-SARSAT EPIRB/PLB system. No one does it better.

I think @CWK referring MRG to Nautilus Marine Rescue GPS

 

[Dan]

Very interesting reading: Solutions for Rescue When Lost at Sea: Undercurrent 04/2018

It says about having MRG & PLB is a good thing. I’m going with Argo to Cocos in September, so this article helps me better prepare for the trip.

 

[Lorenzoid]

Very interesting reading: Solutions for Rescue When Lost at Sea: Undercurrent 04/2018

It says about having MRG & PLB is a good thing. I’m going with Argo to Cocos in September, so this article helps me better prepare for the trip.

Dan, I'm confused about how Undersea Hunter says (in the article you linked to) their system works: "The Undersea Hunter operation supplies a Nautilus Lifeline to every one of its passenger-divers. . . . We equip each of our divers with one of our PLBs, which is numbered and paired with our computable VHF radio units. When a diver fires his unit, it will alert several monitoring posts. An identification number will appear that allows us to head the nearest boat directly to a specific person."

I haven't been following this thread closely, and maybe it has been discussed. But my understanding is that a PLB and a VHF unit (e.g., Nautilus Lifeline) are two separate and independently operating systems. Is Undersea Hunter saying they somehow integrate those systems together?

 

[Dan]

Dan, I'm confused about how Undersea Hunter says (in the article you linked to) their system works: "The Undersea Hunter operation supplies a Nautilus Lifeline to every one of its passenger-divers. . . . We equip each of our divers with one of our PLBs, which is numbered and paired with our computable VHF radio units. When a diver fires his unit, it will alert several monitoring posts. An identification number will appear that allows us to head the nearest boat directly to a specific person."

I haven't been following this thread closely, and maybe it has been discussed. But my understanding is that a PLB and a VHF unit (e.g., Nautilus Lifeline) are two separate and independently operating systems. Is Undersea Hunter saying they somehow integrate those systems together?

I suspect the writer is still confused about the difference between the new Nautilus Lifeline (MRG) and PLB. I have contacted The Undersea Hunter operation about it. They are referring to MRG, not the older generation Nautilus Lifeline with 2 way radio, which is only capable to send DSC alert signal.

The MRG can send out both DSC and the more recent Automatic Identification System (AIS) signalling functionally, which includes your GPS coordinates and a Maritime Identification Digits (MID) user number, that comes in pre-programmed at the factory. The MID is unique to each MRG (e.g., mine is 972-69-6005, where 972 refers to Man Over Board code and 6005 is part of the serial number of my MRG). So, by pressing the red button, Argo AIS screen will display my MID, GPS location, and its distress alert alarm would sound.

When they issue MRG to each diver, each diver’s name would be linked to the MRG’s MID. So when a diver press the red button, Argo will immediately know who is lost at sea, assuming the 1 watt VHF signal with antenna rising 2 feet above the water is strong enough to reach the boat AIS.