The Diamond Princess passing SF on the way to Oakland

[Amberjack]

Beautiful image taken a couple days ago of the Diamond Princess making it way through San Francisco Bay on the way to Oakland. Taken by my daughter in law from her office window. My son who is a sailor was tracking the ship and let her know when it was passing her view slot of the bay.

[Rocky]

Neat shot Doug,
It always amazed me how such a top heavy appearing ship could ever even venture past a bay but I guess they have more than the eye sees displacing water!

[Amberjack]

Hello Rocky--I have seen them out of the water and I agree, there doesn't seem to be enough there to keep them upright. They have dynamic roll dampers in the form of underwater wings to minimize roll but those are only effective underway. I'm with you, it doesn't seem as though they should float upright. Maybe someone reading this can enlighten us.

BTW, my son says the ship has left Oakland and no one seems to know where it went.

[Carl]

From what I have been told, these "Cruise" ships are the Bayliners of the ship world. They are not meant for Ocean going voyages as the norm, ships built for that are called Ocean Liners, like the Queen Mary 2. The Ocean liners sit deeper in the water with a lower center of gravity and big full bows to cut through large waves.

Still your right they look like they should flop over, but motors, equipment, fuel, water and ballast tanks are all down below keeping center of gravity low. While its huge up top, much of it is all lightweight materials with open spaces. When looking at the upper portion its all cabins, dinning rooms, bars and theaters. When at sea as mentioned they use stabilizers.

[Bruce]

" While its huge up top, much of it is all lightweight materials with open spaces"

Carl,
You just described half of Hollywood actresses.

[Carl]

Carl,
You just described half of Hollywood actresses.

Bruce - You owe me a keyboard...I lost a cup of coffee on that one. Funny stuff right there!


...needed that.
Thanks

[ranjr13]

Most use water ballast in tanks which works great, until the pump system fails as happened last fall in a Car Carrier cargo ship that had just dropped off a load of Hyundais in Brunswick, GA. Exiting the harbor (notice green buoy on port of vessel where it lies) the pilot felt it listing 30 degrees, and continuing to lean more until it was intentionally beached to safe crew. No fatalities. It's still there, being cut up this spring/summer.

https://dronedj.com/2019/09/09/drone-vi ... argo-ship/

[Rocky]

All I can picture is a potential loss of rudder control with all that windage and yawing in a downwind quarterly!
Even with ballast, having the superstructure a sail seems dangerous. The rudders must have some depth and power.

[Amberjack]

The more recent ones have multiple directional propulsion pods driven by electric motors so steering is done that way. A year or two ago one of the ships took a massive lurch to one side after a computer issue with the steering. I think the ship went over about 30 degrees which is a shock on a ship set up with an interior more like a hotel than a ship.