Hemmingway liked to use very simple sentences. This brings you closer to the old man, in my opinion. It seems more realistic to use simple sintax. It is as if the old man himself is talking.
Hemingway is famous for his specialized and simple syntax; it's recognizable very quickly to anyone who has read much of his work. The above posts are quite effective in discussing the musicality of his prose; in The Old Man and the Sea there is also the rather clipped and staccato rhythm of an old man from Cuba who doesn't speak often and speaks in a particular rhythm when he does. Take the following line, for example:
Now the man watched the dip of the three sticks over the side of the skiff and rowed gently to keep the lines straight up and down and at their proper depths.
The rhythm of the line (the up and down movement the voice naturally does) mimics the bobbing of the baits on sticks over the side of the boat: "to keep the lines straight up and down and at their proper depths."
Santiago sounds like exactly what he is in this line:
Only I have no luck any more.
It's simple, it's just a bit stilted compared to standard English, and it's quite clipped.
Hemingway's syntax is noteworthy in every way, one of the reasons we still read and study him.
There is musical term known as staccato. The definition is "marked by short clear-cut playing or singing of tones or chords." The musician accents short and simple notes, allowing silence in between. The music does not flow, but "drums" along, note by note.
Hemingway's writing is often staccato. Look at this passage from "Old Man":
They sailed well and the old man soaked his hands in the salt water and tried to keep his head clear. There were high cumulus clouds and enough cirrus above them so that the old man knew the breeze would last all night. The old man looked at the fish constantly to make sure it was true. It was an hour before the first shark hit him.
This is a paragraph of simple sentences. But the purpose of these sentences are not just to provide simplicity, but to create flow. The staccato sense adds to the mood of the novel, the sense of time hammering away at the old man as he tries each passing day to succeed. The pace is stilted, harsh. There is little sense of being "swept along" by the language. Instead, the language - like the conflict - requires constant, repeated, attention.
For a last note, see how different the pace seems if we combine the first two sentences:
They sailed well, the old man soaking his hands in the salt water, trying to keep his head clear while the high cumulus and cirrus clouds looming above let the old man know the breeze would last all night.
Yes, Hemingway's syntax definitely affects the way the prose flows in this story. A sense of flow is produced in part by syntax and in part by word choice. The combination is how sentences are constructed, which, when read, leads to flow. Here's an example: "He no longer dreamed of storms, nor of women, nor of great occurrences, nor of great fish, nor fights, nor contests of strength, nor of his wife. He only dreamed of places now and of the lions on the beach. They played like young cats in the dusk and he loved them." Look at the long first sentence, and at how it lists a series of negatives in parallel phrasing: "no longer," "nor, "nor," "nor." That creates a rhythm, which is part of flow.
Syntax refers to the author's sentence structure. Like many of Hemingway’s early stories, the novel takes full advantage of the author’s widely imitated syntax—a mixture of simple sentences, limited adjectives, and limited but suggestive description. "As Hemingway himself explained in his examination of bullfighting in "Death in the Afternoon", good writing should move like an iceberg, only one-eighth of which appears above the water. The writer who truly knows a subject should be able to leave much of the content unstated, and the reader will 'have a feeling of those things as strongly as though the writer had stated them.’'( from "The Deceptive Simplicity of The Old Man and the Sea" at enotes.com/oldmanandthesea.) Consequently, the simplicity of the syntax does not affect the flow of the prose; it simply makes the reader dig deeper to find more meaning
in this story, which has many hidden layers.