A sailor steps onto land and finds the ground won't hold still. That's the small moment at the center of this short poem. The title, "Shore Leave," suggests time off from a ship, and the speaker seems to be in that position: on land, but still carried by the motion of the sea.
The imagery does a lot in five lines. The day is "bright as silver," so the scene feels dazzling and clean. Then the women in black appear, and the speaker sees them as boats "swimming in the sea." It's a strange, lovely mix of images, with dark shapes moving across a shining background. The poem doesn't say who they are, so we're left to imagine them.
In the last two lines, the speaker calls himself a captain, yet he "rolls" and can't stand. The pride of the word "captain" gives way to a wobbling body. The mood is playful and a little dizzy, with a hint of vulnerability underneath.