Underline the specific name of individual air, sea, space, and land craft.
Captain Bligh commanded the Bounty (sea)
He called the Chevy Greased Lightning. (land)
If an italicized or underlined name appears in the title of a work or some other writing which is otherwise italicized or underlined, the writer has a choice:
1. Normally the specific item reverts to standard type. This is always done in bibliographies and formal references.
Example: Mutiny on the Bounty by Nordhoff and Hall
(Book title contains name of ship)
2. Or you may italicize or underline the title or otherwise italicized or underlined writing without regard to the further italicized words. This may be necessary to avoid confusion.
Example: The Mutiny on the Bounty film starred Marlon Brando.
(Using the style of #1 for this would be more likely to confuse the reader.)