For the sake of an example, if we assume the Baltimore bridge ship was hacked to crash, I think it's doubtful crew could have gotten to and manually actuated the rudder (assuming that was possible) fast enough to prevent the collision.
They got the engine restarted, though, right? If there's a manual override for the rudder hydraulics it stands to reason that would also be located in the engine room, or at least very nearby. So I suspect this incident actually proves they could have responded to a fly-by-wire anomaly, but can't know without reading the report.
My guess is that the rudder hydraulics are not located in the engine room, rather they're in a compartment directly over the rudder (or over both rudders, on a twin screw ship). That's how it was on the destroyer I was on, admittedly a very different kind of ship.
That's what I'm thinking too, and furthermore that the mechanical advantage in that system means that the rudder can only be moved by hand very slowly.
There's probably no way to move it by hand on a ship of sufficient size, only hydraulically, but emergency steering would be a completely separate hydraulic system (separate pump, rams, and mechanical controls) powered by a separate generator or engine. The mode of operation is a person goes down into the steering gear room (as parent mentioned) and responds to instructions telephoned, shouted in person, radioed, or some other way communicated. E.g. "starboard 15°". So your "fly-by-wire" controls can be all kinds of messed up, so long as you can disconnect them and operate the backup system by hand you maintain control.
On a small boat we just have a small cover in the cockpit over the rudder pin where we can insert an emergency tiller and steer "by hand" (realistically need to quickly rig some lines for mechanical assistance but that's okay because the secondaries are right there).
I assume it would be a hydraulic system using hand-power. If it's got electrical/mechanical power and is intended to be an infrequently used emergency system, then you probably have to count on it being poorly maintained and still have a fully manual fallback.
From what I understand, these sort of systems on old 20th century warships ar least are all hand-crank powered.
If they were standing by to do so, then yes, they would be able to take action in a timely fashion. (It is a standard practice on some ships to have such personnel standing by during high-risk situations.)
The question is how much time does it take to realize what the emergency actually is? I'm sure the protocol for "X is broke and doing Y" is probably much different than "X is not broke but is actually being controlled by someone else who may also have control with other systems"
Yeah if they control the systems you use to navigate and assess the status of the ship you might not notice it isn't under your control for quite a while.
