Five short lines, and the ground already won't hold still. The poem gives us a speaker newly ashore, a glaring day, and a crowd of women in black, and then it quietly swaps the roles of land and sea. The women become boats, the shore becomes water, and the one person who should feel at home, the "captain," is the one who cannot keep his footing. Its central idea is dislocation. A body that has lived at sea carries the sea with it, so when it steps onto solid land, the land seems to be the thing that moves.
The opening image is "a day bright as silver." The simile makes the light hard, metallic and a little blinding, and silver is also the colour of sunlit water, so the sea is present before we've seen it. Against that glare come "the women in black like boats / swimming in the sea." The picture is close to monochrome, dark shapes on a dazzling field. Black clothing might suggest mourning, though the poem never says so, and it may simply be a visual contrast. What matters more is the verb. Boats float, and "swimming" belongs to fish and people. By giving the boats that verb, Bonta makes the women's movement look alive and fluid. We can't tell whether the "sea" is the actual sea, or a street or quay that the glare and the speaker's dizziness have turned into one. The poem leaves both readings open.
The sentence structure helps. The first three lines have no main verb at all. They are a held picture, like a photograph of the scene, and nothing in it moves except through the participle "swimming." Then the speaker arrives, and with him the first real verbs: "I walk," "I roll." The colon after "captain" works like a hinge, turning the walk into an explanation. He walks like a captain, which suggests swagger and authority, and the next phrase takes that dignity apart: "I roll, not able to stand."
That last line is the most carefully built. "Roll" is the right word for two reasons. It describes a sailor's lurching gait on land, and it is also what a ship does on swell, so the ship's motion has moved into the man's legs. The comma after "roll" makes the line lurch as well, and the string of one-syllable words ("I roll, not able to stand") slows the reading until each step has weight. "Stand" may carry a second meaning. Besides being unable to remain upright, the speaker may be unable to bear the shore, though that second sense is an inference rather than something the poem states. Either way, it is the last word, and it is exactly the thing the body fails to do.
There is no rhyme and no regular metre. The lines are short, running from about five to eight syllables, and they follow speech more than any pattern. Sound does the binding instead. The hiss of "silver," "swimming," "sea," "shore" and "stand" runs through the poem like water, and "black like boats" packs its consonants tightly. The title then adds its own irony. "Shore leave" means permission to go ashore, which implies a temporary freedom and a ship waiting somewhere behind the poem. The word "leave" also hints that the speaker belongs to the water and is only visiting the land.
The poem is worth reading because it does so much in so little space. It never explains the speaker's feelings, and the reader feels them anyway, through a reversal of images and a stumbling last line. It also makes a quiet point about identity. The speaker calls himself a captain, a man in command, yet his body has its own loyalties and won't obey the solid ground. By the end the reader is slightly unsteady too, unsure which of the two, shore or sea, is the real one.