Writer seeking help... can a ship lose ALL comms?

This wouldn’t be very difficult, however, that only solves the problems of the main communications. The villain would still need some way of disrupting all the handheld and portable things. EPIRB, Handheld VHFs, etc. Either the ship needs to completely blackout (including backup batteries and generators) or the baddie needs to disable each piece of comms equipment individually. In the first case, there would still be the portables, in the second case, the risk of discovery before getting even half-way through it all would be very high. I would also say the villain would need to be a watchstanding deck officer on that ship to have the access and knowledge to even try.

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Difficulty in disabling handheld devices would also depend on what type of ship. If it was a cruise ship, for example, it would get tougher. I assumed that the ship would be mid-ocean w/o other vessels in line of sight so cell phone and VHF would not be usable. But if it was a passenger vessel, I’d guess that some of those passengers might have something like a SPOT. Additionally, many crew carry their own PLB that works on the EPIRB frequencies. Possibly some passengers carry those as well?

Many thanks again. This is excellent. I’m assuming a very well equipped villain – it’s a planned thing with people with a lot of resources. It’s a very high-tech modern private yacht and I’m hoping, as a result, more hackable than most. How plausible would @Klaveness’s solution above be:

A well engineered jamming signal transmitted onboard would effectively prohibit reception on all bands and transmission on any device requiring a handshake, which includes cell phones and satcom. It could also be designed to blank out radar reception and positioning. You could still transmit on HF / MF, but not all ship carries such equipment.

This also goes for @portofdc’s answer, which appears to my original idea. I’m still clinging on to it for dear life.

I’m unfamiliar with the power and limitations of such equipment, but the military does have EWar equipment capable of such things, and has for decades so it’s no secret. A villain, or evil organization, could get its hands of such devices depending on just how well funded they are. You could go totally James Bond Villain and make up the jamming technology, without going into too much technical detail, or how they acquired/afforded it in the first place.

I don’t know the UK equivalent to the FCC, but you could have an inspector from such an agency be the confederate/blackmail-ee of your baddie. In the US this work is farmed out to vendors, often the same vendors who service your electronics.

The inspector goes through the usual big inspection of all GMDSS equipment and somehow rigs it all to fail at the same time.

The electronics guy who works on my ships is a master craftsman. Not only does he work on the comms electronics, he also works on the computers, the nav electronics, and the handhelds. He is forever diagnosing how other electronics affect these. For example, some years ago he told us not to use LED light bulbs in a certain area, because they were emitting a frequency that interfered with something important. He is also famous for making Faraday cages around bits of electronics using copper sheets, to minimize their interference.

I think you get where I’m going. Blackmail a guy like this, and he could plausibly render all shipboard electronics null and void at a certain stage of the journey. He could “test” the EPIRB before departure, when really he is disabling it, and do the same to the EPIRBs in the lifeboats (don’t give you ships liferafts, though, because he wouldn’t have access to the EPIRBs inside.

Put your ship in deep ocean, and handheld VHFs would only be useful if another ship passed within 20 miles. Probably more like 10.

Now, to explain away how personal electronics would be useless…

  1. Put your ship in high latitudes. 50 degrees plus. Until about 10 years ago, the Bering Sea and Arctic Sea were poorly served by satellites. (Maybe the south polar seas too. I don’t know. Maybe our Kiwi friends will chime in.) You could plausibly say that most brands of satellite phones a private person would buy wouldn’t work reliably in such areas. Which brings up…

  2. The farther back in time you put your story, the more plausible it is. Up to the 1980s your premise would be easy. Every year after that it become harder, until the 2010s it’s highly implausible.


I recall a mate who was told he’d be leaving the boat in the next port but if he just laid in his bunk till then he would only receive half his pay. He had a bad attitude and always talked back to the skipper but I can’t recall exactly what he did to be fired. On his final watch as a parting gift he went deep into the settings and reprogrammed the boat’s radio to only receive and not transmit(he was a radio nerd like the young officer that Klaveness talked about). We thought it was a problem with the mic/handset. We just used the handhelds so it wasn’t that big of a deal. It wasn’t till the mate was long gone and tech came to the boat in port that we figured out that the radio was reprogrammed. I did not pay attention to the fall out(above my pay grade) but I do recall there were serious legal consequences(both criminal and civil).

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On my particular vessel, the villain would be better off killing us. On a smaller boat, if it wasnt weather related, problems get noticed pretty quick. With radios. 2 sat phones, sat email, garmi ns, epirb, and depending on location, cell service, just kill the crew if its a small boat. Or tie us all up.


“… but not all ship carries such equipment.” Might be worth looking at GMDSS and SOLAS requirements.
Since the “ship” has changed to “yacht” with passengers there are a couple of new wrinkles to consider. Is it operating as a charter yacht or private? What flag, where does it operate, what sea area?

I have yet to see a large yacht that does not have a GMDSS suite and certainly no cargo ship in anything but coastwise trade that is not required to be fitted with GMDSS MF/HF.

Low tech ways to disable some of the comms equipment, if a electronics tech had access to it of it as described above:

The Achilles heel of radio equipment is the antenna. Disable the antenna and everything will light up, but no joy.

The Achilles heel of sat coms is the dish. Disable it, and you take out most (but not all) sat comms.

Your baddie could have access to vials of composite filled with acid. Such that after so many days the acid eats through the vial. Make it Cold War skullduggery tech. Who cares if it doesn’t exist. It’s more plausible than EMPs, etc. The electronics tech tapes a vial to the cable in the antenna coupling box for each SSB antenna. These coupling boxes are 8” x 8” or bigger. So no problem, He does the same to the drive motor of the sat dish.

After X amount of days the vials all leak acid at the same time. Eating through the antenna cables and disabling the sat dish drive.

You would still have to account for all the other personal electronics. Hence, put your story in the past +10 years.

Once last hurdle for you. All modern vessels travel in a Bubble of Accountability. Because there are so many ways for a vessel to communicate nowadays, she is expected to communicate. There are daily reports back and forth between the home office, and even more comms between the crew and their families.

Once this bubble goes down, people go ape shit. Forget about the EPIRB. If a ship with passengers goes black nowadays, SAR forces are going to go looking for it immediately.


Assume we are talking about an actual ship: The answer is not really,. The ship will have VHF, HF, and Satcoms permanently installed along with a number of handheld VHF and UHF radios plus at least one EPIRB, one or more AIS units, and however many PLBs/EPIRBS are in the lifeboats and personal gear of the crew.
A bunch of pirates would have to very quickly overwhelm the crew and go about finding and disabling a whole bunch of gear. I know of at least one sat-com system with a “pirate button” you can push pretty fast.
Realistically it would have to be an inside job.

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The choke point in the GMDSS, both sat and radio is the AC/DC power supply.


Ship’s service generators (SSG), Emergency Diesel Generator (EDG) and battery all pass there. Both SSB (radio) and Inmarsat-C (satellite) depend on power.

Edit: Power for the bridge VHF radiotelephone also is via the AC/DC power supply.


We’re all telling him how to do it with very good technical information. Surprise he’s actually planning a real life heist/murder.


In that case, I suggest spraying the ship with whipped cream. It is a known to be opaque to RF and mariners are afraid of it and will jump off the ship to their deaths rather than be exposed to dairy products.
You also could come alongside with a big neon sign saying “Whores 50% off today only” and they might all abandon ship voluntarily. While they make the unwelcome discovery that 50% off was describing the status of their sex change surgery, you climb on their ship and make a hasty exit from the area.


It’s a yacht. Doesn’t that describe the second night out dinner party or is Down Below got it wrong?


Heh. Strokes white cat.

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This is brilliant. Thank you. I’m beginning to think it’s a mixture of this and jamming for hand held devices.

We are talking a kind of GRU/KGB operation so tech is theoretically no problem.

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Yep. It is an inside job and I think that the PLB/EPRIBS stuff is OK because, if I understand it right, (and I’m googling a lot of acronyms here!) it shows position and the fact that there is an emergency, but doesn’t allow direct communication with the outside world, which might suit my plot.

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The problem with going after the power is that jury rigging a fix is such a trivial matter that even the dimmest of engineers would stumble upon the idea pretty soon. If we’re talking about temporarily powering a single radio, that can be done with torch batteries or pretty much any other power source on hand.

Wide spectrum RF jammers are easy to construct and even easier to buy on alibaba. If I were to contemplate such a thing for myself, I’d choose one that sweeps the spectrum at a rate of 50 Hz, so as to convince the troubleshooting engineers that it’s a power issue.

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Thanks again. I’ll have to give that some thought.

Do note if someone was taking my boat/ship someplace and it suddenly vanished off of Marine Traffic (https://www.marinetraffic.com), I would be trying to find out why pretty quickly.