Oosterdam’s original azipod, replaced in fall 2007 with a “spare” is back in action now and being reinstalled during this dry dock.
Work is also required on the bow thrusters, but how do you get them out when the hull is built around them? Simple!
You cut them out! Here you can see the piece of hull plating taken off the front to obtain access. What happens when the repairs are made? The thruster will be replaces and the hull will be welded shut again.