Leonhart
Imagineer
Since Team Rocket managed to infiltrate the S.S. Anne easily I've always wondered if Giovanni owned the cruise ship. When Ash gave up Butterfree for Raticate, it was a betrayal.
I don't think Sakaki owned the vessel. I think he merely planned ahead and placed all those Rocket-dan grunts there with help from Musashi, Kojirou, and Nyasu.