We've been thinking that the primary Leaf delivery ship so far as been the United Spirit. It made the trip from Japan to LA a few weeks before Gudy's delivery, and has made another trip to LA and now apparently to the Vancouver area.
Certainly the ship has more then just Leaf's on board.
Watching Oppama, it appears that ships sail assigned routes, as we've seen the same ships come and go from the same places repeatedly. That would leave us to believe that the United Spirit is worth the effort to continue to watch. We also saw one of the Aces sail from Japan to LA, so will keep and eye out for that too.
I haven't seen the United Spirit dock a Oppama - quite possible that I've just missed it. But with the small number of Leaf's delivered so far, I'm speculating that another ship has picked the Leaf's up at the Oppama plant and transported them to Nissan HQ, which is further north in Toyko Bay. (A number of ships have made that trip) We have seen the United Spirit stop at HQ before each crossing, so maybe the initial Leaf's are getting the CEO inspection (Carlos sat here!). Check those door panels for the seal of approval.
We are led to believe that March and especially April will see a significant increase in US deliveries. With this, I'd guess that the thousands of car we expect to be delivered will be loaded right from the plant. It looks like this takes 12-24 hours, based on how long other ships have been docked at the plant. So - keep an eye on Oppama and maybe we'll actually see the big shipment of Leaf's loaded. Assume two weeks for the crossing and at least two more weeks at the dock for US inspection.
It looks like a ship can carry about 2000 units (at least that is what is listed for the St. Petersburg), and it takes about a month for a round trip - so if Nissan intends to deliver more then 2000 Leafs in a month, there will have to be more then one ship involved.