PLBs and DSMBs

[Scraps]

Correct, in that the alert that goes to the satellites would send messages to your agency. If registered in the US, then to NOAA, who will call your registered contacts. If they know your schedule, that may help expedite local efforts. If the boat radios local authorities that you're missing but have the PLB, that too will help. If the members of that team effort work together, it all helps. The Coast Guard boats and helicopters can also search for your homing signal and radio others when you are located.

That's almost, but not quite the process.

The signal goes from the satellite to local user terminals (the network of ground stations) to the NOAA-run US Mission Control Center. Other countries have their own MCC's. There are also MCC's in Russia, France, Australia, Japan and Spain.

USMCC then relays it to the Air Force or the Coast Guard, according to the assigned areas of responsibility in the National Search and Rescue Plan. Generally, the USAF is responsible for inland locations and the Coast Guard for water (there are exceptions: for example, USCG has inland SAR responsibility for Puerto Rico).

If the Coast Guard gets the signal, it will be further relayed to the area, district or sector command centers, depending on who has SAR Mission Coordinator responsibility for the source location. Then the callouts and marine broadcasts begin in an attempt to correlate the signal to an emergency.

It's a great system if you're out of VHF range, but it does take a little while to lead to a launch decision. If you're within range of the CG's VHF network (generally 20 NM of shore), a call on channel 16 is your fastest way to get a response. They'll have your position as soon as you key the mic based on bearings to adjacent high sites, and they can replay and enhance the audio of your distress call to make sense of it.

 

[Dan]

Here’s the expert’s explanation about why & how the PLB works:

 

[BlueTrin]

Yikes. I'm doing the deep south of Maldives in February. Each of us has a DSMB and DAN Guardian insurance, but I'm wondering if those will be enough...

I should sell PLBs and advertise on scubaboard

 

[boulderjohn]

I was convinced to buy my PLB years ago after a harrowing story of divers lost at sea for a very long time. Some died, IIRC. I bought it in anticipation of risks of that nature on my planned trip to Indonesia.

Once I got the PLB, I had to find a housing for it, one suitable to depths of at least 5 atmospheres. There weren't many good choices. I found one advertised for that very purpose, and that is what I got. It is one big, bulbous hunk of gear, so there is really no good place to stow it. It came with a carrying case with a loop of webbing obviously designed for threading onto a waist belt, but The instructions said not to take it in the water. Seriously. What is the purpose of a carrying case for high pressure housing that can't go in the water? So I gave it a shot in the water anyway and it lasted two local practice dives before disintegrating. I ended up attaching it with a bolt snap and line, meaning I had a big black blob banging around by my waist.

As it turned out, in that 3 week trip to Indonesia, I don't believe I ever surfaced more than a 5 minute swim to shore. I felt like a damn fool carrying a PLB on dives where I could talk to passersby on shore, so I stopped using it pretty quickly.

So I now have had my PLB for a number of years, and I have only used it a handful of times because I have not done all that many dives where I think there is a possibility of a problem.

I have never seen anyone else with one. I do not feel I am superior to other divers because I own a PLB and they don't. If 99.937% of the world's divers are not carrying PLBs, I am not shocked when I learn that someone does not use one, and I don't consider such a person to be an inferior diver.

 

[waterone]

The mini inReach is tiny and fits in my thigh pocket in its waterproof case. I never thought about this superior thing you guys got going on, but now I'm going to tape it to my chest so everyone can see it.

I personally am shocked when I hear a diver has gone so far out (in this case around 12 miles offshore) and doesn't have something in case they get lost or that a version was not provided by the OP. If I cannot swim easily to shore, I will carry something. If for nothing else, I can text my friend to say ready the Tequilla.

 

[Celt]

I know it's done but personally I wouldn't have faith in a stranger finding me if I drift off aimlessly on a dive in the hope that a boat will be there when I surface. Offshore, when the option to swim to shore isn't there, I'm always attracted to my boat so have no use for a PLB. If I break down I'm in range of VHF.

 

[kinoons]

Just spitballing - I’ve seen multiple dive containers for a PLB and as noted they are all pretty damn big.

The issue is that with pressure water could ingress into the device, correct? We’re not worried about the depth and pressure physically destroying the device.

Would it then be appropriate to vacuum seal the PLB? The bag is impervious to water, and you can tear it open if you need the PLB at the surface.

 

[boulderjohn]

The mini inReach is tiny and fits in my thigh pocket in its waterproof case. I never thought about this superior thing you guys got going on, but now I'm going to tape it to my chest so everyone can see it.

This was not available when I bought my PLB. It clearly has a lot of advantages over what I was able to get back then.

 

[Joneill]

Just spitballing - I’ve seen multiple dive containers for a PLB and as noted they are all pretty damn big.

The issue is that with pressure water could ingress into the device, correct? We’re not worried about the depth and pressure physically destroying the device.

Would it then be appropriate to vacuum seal the PLB? The bag is impervious to water, and you can tear it open if you need the PLB at the surface.

I think that, in addition to water ingress, you are also somewhat worried about the pressure physically destroying the device.

 

[Pressurehead]

That’s not a PLB. This is a PLB

Ok , I was talking about my Nautilus Lifeline Marine rescue GPS, I have been looking at a PLB here, they cost $349 AU [the one you have], the GPS cost around $300, and it was on special when I bought it.
I think we have gone a little off topic.

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