A wind instrument makes no sense because of the missing sector. You need to know it all the way around the compass especially on a carrier where you have to turn into it - how do you do that if you can't see it in a certain sector? No, it isn't that. Arguing that the dead sector is because of the island makes no sense because the island is on the stbd side, not port. You can't "use" wind from astern on carrier air ops either so why would it be calibrated all the way to astern on one side and not the other? You can't "use" the wind 40' either side of dead ahead in a sailing boat but the wind instrument still shows it because you still need to know it.
All the rudder position indicators I've seen have been clearly annotated as such and only range 30' or so either side of ahead. No rudder can turn 180', so why annotate it?
It could indicate logically as a repeater for a rotating power-pod type thruster but they're far too modern for this instrument, aren't they? Even so a rotating thruster is a bit handicapped of it has such a large dead sector on one side.