This poem begins with a reflection on two kinds of time: time as the clock measures it, and time as the speaker experiences it. Clock time, "moved by little fidget wheels" (fussy little gears), is "not my time," the speaker firmly declares. Rather, he's in a kind of time he describes as "the flood that does not flow," a metaphor that suggests a supernaturally still ocean. ("Flood" here means "sea," not "overflowing water.") Unlike clock time, this kind of time doesn't "flow," doesn't move relentlessly forward at a steady rate; unlike clock time, this kind of time isn't "little," but vast as the sea.
In this unmoving "flood," the speaker says, he can live "many lives" in the space "between the double and the single bell / Of a ship's hour"—in other words, in the half-hour interval that marks out a watch (a period of work) on a ship. That image occurs to him as he looks out at a "dark warship" down "below" him in the water of what readers will discover is Sydney Harbor. As this ship's bells ring out, he seems to be in a pensive mood, lost in this mysterious kind of infinite-but-motionless time.
In particular, he's living out "one life" over again, and it isn't his own. It's the life of "Joe, long dead." Readers who are familiar with Kenneth Slessor's life story will know that this "Joe" is a real person: Joe Lynch, a friend of Slessor's who accidentally drowned in Sydney Harbor. No wonder, then, that the speaker is brooding over Joe's life as he looks out over the waters.
This poem will become an elegy for Joe, written in dignified blank verse—lines of unrhymed iambic pentameter. (That means that its lines are built from five iambs, metrical feet with a da-DUM rhythm, as in "Between | the dou- | ble and | the sin- | gle bell.")
Joe, the speaker goes on, now "lives between five bells"—a line that suggests that Joe's "life" only goes on in the kind of time that clocks can't measure. He's not even in the half-hour interlude between "a round of bells," but in the space between each individual chime that makes up "five bells," the signal that marks either 6:30 p.m., 10:30 p.m., or 2:30 a.m.
Joe, in other words, only lives on in memory, which isn't bound by the rules of clock time.