The old idiom "The devil's in the details" has, in my experience, been proven true time and time again. The "big picture" may look fine and dandy, but there's always something, some little detail that's escaped attention, that can screw it up to a fare-thee-well.
The Norwegian Navy learned that the hard way last year, when its frigate Helge Ingstad collided with another vessel, and subsequently sank.
The subsequent inquiry revealed that after the collision, the watertight compartments of the frigate functioned as intended . . . except for one crucial detail.
While there was some uncertainty as to whether the steering engine room, the aftmost compartment, was also filling up with water, the report states that the crew definitely found that water from the aft generator room was running into the gear room via the hollow propeller shafts and that the gear room was filling up fast.
From the gear room, the water then ran into and was flooding the aft and fore engine rooms via the stuffing boxes in the bulkheads.
Based on the findings, AIBN has recommended Spanish shipbuilder Navantia, the vessel’s designer, to look into the issues identified during the investigation and to determine whether this was also an issue with other vessels.
There's more at the link.
Uh-huh. The "technologically advanced" hollow propeller shafts may have been as much of an advance as claimed during normal operations; but they had to penetrate more than one watertight bulkhead to get from the engine-room to the propellers. When the shaft(s) was/were breached by the collision and/or the subsequent grounding of the frigate, inrushing seawater had a clear path from one compartment to the other, effectively destroying the ship's watertight integrity and leading to its total loss. The cost of repairing it will be greater than the cost of a new ship, so it'll be scrapped.
I wonder how many other modern vessels have incorporated this technology? After the experience of the Norwegian Navy, how many of them will have their "advanced" hollow propeller shafts replaced with the good old-fashioned version? Is that even possible, given that a ship's propulsion systems are a series of machines finely tuned and adjusted to work with each other? Can the engines handle the increased mass and inertia of heavier, solid shafts? If they can't, those ships will have to live with reduced watertight integrity. That's not going to make their crews happy . . .
Devil, meet details. Details, devil.