Answer:
The poem is loosely structured overall but does have some elements that make structure.
Explanation:
The poem does not rhyme and is very freely written. but it does start with "The" in most lines as it tells us who is singing:
<em>"The carpenter singing his as he measures his plank or beam,
</em>
<em>The mason singing his as he makes ready for work, or leaves off work,
</em>
<em>The boatman singing as he sits on his bench, the hatter singing as he stands"</em>
So, considering the verses above, it would be correct to say that it has some sort of structure.