Navy sailor here. Trained in celestial navigation. The 3 clocks thing is for real. On my first ship we still had mechanical clocks, on the theory that an EMP wouldn't bother them.
Captains have navigated oceans in rowboats to fetch rescue and survive mutiny.
It all starts with knowing where you are and where you intend to go.
Also: Ships aren't neccesarily killed by EMP - mechanical engines still work, they can be tuned by hand, rudders are operated by levers and hydraulics, these can be manually moved, etc.
Yes, but the scenario where you're relying on a mechanical clock because it survived an EMP attack is the scenario where you're getting attacked with nuclear weapons. Which... I dunno, the idea of rowing to safety seems a bit implausible in that scenario?
As for mechanical engines still working -- I would assume there's electronics in any modern hydrocarbon engines, for efficiency reasons (adjusting engine timing etc), never mind nuclear powered ships.
Well, EMP bursts going off overhead is not the same as being attacked by such weapons - the scenario planned for would be maximal operation after an EMP burst.
Dunno about you but I still have my working early model Sun workstation (pizza box years) rated to survive EMP with shielded casing, monitor, etc.
> I would assume there's electronics in any modern hydrocarbon engines
assume .. so, you've never worked on a container ship as a mech engineer babysitting a Wärtsilä RT-flex96C and you think the navy has a lot of nuclear powered ships then?
Have a deep think on this - do you think the US military designs ships to be useless when the electronics go?
No capability for manual weapons aiming, no ability to operate the engines or steer?
We've got a navy person commenting upthread here about having three mechanical clocks for longitude estimation in the event of no GPS .. what do you think that's all about?
early model Sun workstation (pizza box years) rated to survive EMP with shielded casing, monitor, etc.
Obviously, while it might survive some EMP, there's a limit to the efficacy of the shielding. Anything your Sun workstation would survive is trivially survivable by a quartz watch sitting in a shielded box.
you think the navy has a lot of nuclear powered ships then?
My understanding is that the entire submarine and aircraft carrier fleets are nuclear powered, yes.
Have a deep think on this - do you think the US military designs ships to be useless when the electronics go?
I think in a nuclear war scenario, surface ships are already useless (and most likely vaporized) so maximizing the efficacy of their navigation systems in such a scenario is probably not a priority.
We've got a navy person commenting upthread here about having three mechanical clocks for longitude estimation in the event of no GPS .. what do you think that's all about?
My guess is that the three mechanical clocks was more a matter of tradition than efficacy in modern warfare.
> Obviously, while it might survive some EMP, there's a limit to the efficacy of the shielding.
It was EMP rated by US nuclear agencies and used for nuclear test monitoring and radiometric surveys.
> the entire submarine and aircraft carrier fleets are nuclear powered
which leaves a lot of other ships .. and avoids the puzzle of why they wouldn't be able to function after an EMP burst - do you think you're the first to think of such a thing and no one has modelled about such an event?
> surface ships are already useless (and most likely vaporized)
You're assuming that an EMP burst high in the skay also vaporises all ships (or other weapons do), the design of military ships is to assume that they still need to function when damaged to a degree.
> My guess is that the three mechanical clocks was more a matter of tradition than efficacy in modern warfare.
You're hung up on warfare .. navigation may fail for all manner of reasons and three clocks for reference in determining latitude (after allowing for mechanical error) is a matter of sound numerics rather than crusty tradition.
Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time by Dava Sobel is decent introductory read if you'd care to guess less and learn more.
