The cause for that accident seems to have been strong wind, which apparently makes these huge ships very hard or even impossible to maneuver when they are going slow.
If true, then the "systemic issue" is only that ships are getting too big.
If true, then the "systemic issue" is only that ships are getting too big.
Ships of ANY size are hard or impossible to maneuver when they are going slow and have a blackout. The size doesn't matter.
The control surfaces only work when they move with regards to water.
The ship that does not move is uncontrollable with rudder and it needs to use something else to help it maneuver. This something else can be a tugboat that rotates the ship by the force it can generate, or it can be thrusters. Thrusters aren't propulsion method and they are relatively small and can counter only so much wind.
I think the biggest issue is complexity and resulting unreliability. On a ship that has to be in constant use for decades you want things that are simple and reliable.
"The latest design, the Azipod X, incorporates these improvements, with a view to a service interval of five years, and features bearings that can be taken apart and repaired from inside the pod while the ship is harbored normally"
Yeah, that pretty much sums it up. They are working on it:)
Also an important factor on large vessel is fuel efficiency. You don't want anything sticking out unless absolutely necessary, so these would have to be meant for propulsion. But because of complex construction I can expect they are less efficient than just straight through axle and a huge propeller on it.
I expect things like this to be useful on utility vessels of small to medium size where you don't necessarily need so much efficiency but the utility comes from being able to maneuver quickly and in various conditions.
They're quite efficient (although maybe only for lower speeds) and provide extreme maneuverability.
When the fuel efficiency and reliability drive your competitiveness that is a huge issue.
They use large two stroke diesel engines which can be stopped and started in reverse. They use an extra valve in the engine head to admit air for starting and have valve gear which controls the direction.
Cruise ships on the other hand have electrical house loads which are almost the same as their propulsion loads. In addition to the manoeuvrability advantages this makes diesel electric drive advantageous.
And yet, they were unable to prevent the wind from pushing them into a moored ferry they were passing.
The engine can most likely work both directions equally.
The propeller is optimized to work in forward direction, so it will have worse efficiency going in the other direction.
The rotation would have to be limited when going in reverse because of cavitation (and maybe other structural limitations). That again is a result of the wrong shape of the propeller (when in wrong direction).
The hull will have significantly more drag when in wrong direction.
Now, engine power is defined as whatever it can put out and if the engine works the same way in both directions then power is the same also.
So you can think this way: most likely it has the same power as going forward but it can't use it and whatever it can use will be much less efficiently translated into motion.
The more descriptive cause is the failure to pay for adequate tug support/escort.
"(Escort tug charge) = 6,600 SDR/tug"
The article cites a tug captain as saying that they have a very limited ability to react to big ships being pushed by strong wind. They compare it to driving a care on ice.