• Starting to notice any similarities? These guys are all laborers. They're all at work. Even more specifically, they are manual laborers, who work with their hands.
• Not everyone can sing at work after all. If you are a lawyer making your case in court, you can't exactly burst out into a rousing chorus of "America the Beautiful," can you? We think not.
• The singing workers are all dudes who do tough manual labor—the carpenter making his measurements, the deck-hand ready to work on the steamboat deck. This is unglamorous work for sure, but through their singing, these laborers take joy in what they do. Note the sense of ownership in the poem; the mason is "singing his" song, while the boatman is "singing what belongs to him in his boat."
• These guys are proud of what they do. And the speaker is proud to acknowledge their work (and their awesome singing voices) in this poem. He's shedding some light on people who don't often make appearances in poetry (especially in nineteenth-century America).
• But we've got to ask a question: is the speaker painting a too-rosy picture of these workers? These can be dangerous jobs, after all. What is he leaving out of this picture? Let's read on to see…