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/
this post was submitted on 17 Nov 2025
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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.
Any chance what you have is not an EPIRB, but a SART? SARTs are only registered with beacon ID and doesn't require programming. Shows up on radar and sometimes AIS also. No sat comms involved.
Registration Status: Registered.
Beacon Type: EPIRB.
406MHz GPS (Cat. 2) 66-channel. Beacon Status: Operational.
Battery Expiry Date: 01/10/2028.
It's UIN—which I obv won't give lol— doesn't hold an MMSI. The main reason being EPIRBs aren't just for marine craft.
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.