The problem here ERC is that I don't know what "civilian" standard means, and I doubt if anybody knows.
Manning is much more a function of the duty of the ship at stake.
Take a modern bulk carrier. It gets out of harbour and basically, comes up to transit speed, switches over to heavy bunker, and stay at that speed (and almost on that course) for the whole transit to say Europe. It has a single medium speed diesel engine turning fixed pitch screw through a simple straightforward gearbox, a single diesel generator and one emergency generator. The chance of a breakdown in the engine room is pretty low, and if it happens, then you just drift while the chief engineering mate and his crew make the repair. A total engineering department of one Chief mate and two assistant, none of which stand watch, to deal with ongoing maintenance (limited really to cleaning the oil filters in rotation and the injectors sets) is more than enough. Same goes for bridge crew: one officer to plot the GPS fix every hour and otherwise keep an eye out for the one or two other large ship they may cross path with in any given watch (remember they are mid-ocean), 90% of which encounters require no maneuvering , is more than enough. As there is no "ongoing drills" all the time, and they have all the same watches all the time, six people are enough. Add the captain and the cooks and you get a crew of eleven. And that's enough for what is, in effect a truck.
But go onboard a cruise ship, where the seaman's crew is responsible for thousands of human lives, and suddenly, this truck like basic manning is far from sufficient. You will see bridge crew and engineering watches much closer in composition and number to the ones we use in the Navy, and the overall number of seaman goes up accordingly, with most cruise ships having "seaman" (i.e. excluding the "hotel" personnel) crew closer to about 120-150 members, about half of which are engineers of some description.
You have the same situation for, say, a deep diving support ship: crew of more than 100, in large part engineers, to make absolutely sure that nothing, underline nothing, breaks down or malfunctions while the divers are at depth.
And you have everything in between depending on the ship's task. So I ask again what does "civilian" standard crewing means?
Now, for the Navy, if all we ever did was drive around at constant speed going from A to B, (I am sure Lumber will agree here) we could reduce the number of people on watch, and with nothing else but watch keeping going on, we'd be standing one in six or seven with the numbers we have onboard. But that is not what we do. We are warships and when out of harbour, we are either on an operation or training for it. Either way, it requires more people and it takes a much higher toll on all the equipment - which is constantly and harshly solicited by our maneuvering - which in itself requires more maintainers and since we have a lot more equipment (read engines/gearboxes/mechanical devices) than the standard merchant ship that also means more maintainers.
But there are still ways to reduce personnel in the navy overall or reduce manning to face critical shortages. One way is to accept that, other than the ships deploying on operations, where you do need everyone (try do an Ocean Safari, for instance, without a full crew) when going out to train only, you could reduce the operations side to a single watch and do all the training during the work day only, then just steaming around with minimal watch on deck at night. You then augment such crew when it is about to go on operations somewhere.
A word of caution, however: This can work as a temporary measure when critical shortages exist or as mean to provide the non high-readiness ships with leave and sending personnel on career courses or easing the tempo for family reasons but it cannot be a long term plan. If all hell broke lose, you have to be able to fully man every ship in the fleet, so overall, you need to have the numbers available to do that. In the end, automation is the only way to go long term for crew reduction, as long as we accept that in case of breakdown it may reduce the ship's fighting efficiency.