Would be a bit wobbly if it was only on top... That might be how the containers ended washing up on the beaches near here a while back.
We crossed the northern Pacific 4 years ago on an "upper berth" with the Fleetwood. (YES, it was insured via marine insurance)
We were being unloaded in Taiwan to catch a different bus, so got to ride further up than most.
We then went on the CAT service, China, Australia, Taiwan, but we scored a spot down a bit, as it went Mel, Syd then Bris.
Logistics on who goes where would be a head fukk I reckon.
As for Shit lasting, car batteries last about 17 minutes past the 2 year warranty...... but....
The battery in the Fleetwood, was new in 2013 in Los Angeles and is still going like a trouper 7 years later.
It is a big fukker, @ 950 CCA, but it did go flat on the trip here from the US when some Muppet left the ignition on acc in the USA.
It was flat as a battery could ever be..... charged it up and never an issue since.
Just goes to show, a battery can be built to last like they did in the old days, they just choose not to.