Title text:
‘Oh no, the box is drifting out into the harbor!’ ‘Yeah, I wouldn’t worry about losing it.’
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3169/
For those who didn’t know: EPIRB = Emergency Position Indicating Radio Beacon. Sends an emergency signal via satellite and terrestrial RF. They can be triggered manually, but they also trigger automatically if salt water shorts two exposed pads for a certain amount of time (a minute, I think).
Once triggered it will get a GPS fix and transmit a distress signal via satellite and VHF. It is programmed with the MMSI of the ship it belongs to.
Works all over the world, although they take a bit longer to successfully transmit the signal in the polar regions as they then have to rely on LEO sattelots in polar orbits.Source: I have a GOC, and I also used to work with marine electronics. I’ve programmed hundreds of these. Mainly
JordanJotron TR60 (Ducking autocorrect). Some from McMurdo too, don’t remember the model name.Fun fact: A coworker did have to make the phonecall of shame to the coastal radio after accidentally dropping one overboard.
what does programming them include? Just a ship identifier?
I have a handheld one—to float with me in a liferaft, etc—and it gets registered to a vessel or vehicle. Whenever I want to use it on something different, contact the federal government, advise of the new vessel ID or vehicle registration, and it’s now associated with the new one.
I don’t think it matters much since it is a beacon after all, but I think it helps in searching. Also, a lot of other details are registered along with it so they know who to send the tens of thousands in fines to if I somehow bypass all three “Are you really sure?” switches and fire the thing off inappropriately.
It’s been a while, but off the top of my head: MMSI (which is basically the radio installation identifier. Same number is used for AIS), and an ID digit (0 in wheelhouse, 1 on starboard bridge wing, 2 on port, etc)
nice, so plug it into a laptop, get it programmed, then drill it onto the ship?
Yes, except no plugging involved: It’s some sort of inductive way of programming it via a USB dongle. The info is written into this “programming program” which can read and write data to the unit, it’s written, and then you read it to make sure all the info was applied.
Then you label the unit physically with ship name, callsign, and MMSI. In addition to this there are two stickers that come with the unit, denoting the expiry date of the battery and the hydrostatic release. These go on the unit so that’s it easy to check if it’s time to replace them.
When I worked for a scrap metal recycler someone dumped a load of electronics and didn’t tell us there were EPIRBs in the mix. We found out when the cost guard, police, fire and ambulance turned up.
The coast gaurd get an @everyone
What are you zinking about?




