Salty Dog by Gloria & Ted Rand (1991)

Zack, a boatbuilder, acquires a puppy with the intention of making him a seagoing dog. The two ride the ferry between home and work, and tiny Salty wins the crew's affection. At Zack's boatyard, Salty is kept in a box to avoid danger. But as Salty grows too big for a box, he must be left home alone.

Missing Zack, Salty digs out under the fence and hops aboard the ferry on his own. Soon he becomes a regular commuter. When Zack finishes his building, Salty is outfitted with a life vest and taken on his maiden voyage on the boat that now bears his name. This engaging and affectionate tale is illustrated in brilliant watercolor spreads that pay close attention to detail.

The rich atmosphere of a seagoing community is nicely evoked, and Salty appears in every illustration, growing from adorable miniscule pup to well-behaved dog.