JAY spends all his free time high upon the cliffs of Dover, watching the sailing ships below. All he wants is to go to the sea, far away from the grief that lingers at home.
When his father introduces him to his uncle, a Portuguese merchant, he joins his ship. TRISTAO, RUI and MIGUEL try to help him, [Who are they?] but he does not trust anyone. [Try to help him do what? Why doesn't he trust anyone? Joining the crew of a ship on which you trust no one: not too smart.] [Too many pronouns in this paragraph.]
Arriving in Lisboa, Jay puts himself in his uncle’s service. [Not sure what that means. Didn't he put himself in his uncle's service when he joined the ship's crew?] His travels lead him to Venice where he meets a tavern wench, LAURA, who both puzzles and intrigues him.
With every journey he makes, he grows closer to Laura. This frightens him and he escapes, [Escapes? He's been leaving every time his ship leaves Venice. How is this any different?] joining his friends on an adventure. Not all goes as planned [What was the plan and what actually happened?] and adrift on the ocean, Jay reflects on his life.
He returns to Venice, but finds that Laura has a husband and a child. [How long was he gone?] Embittered [Crushed?] he leaves her behind. [What other option was there? Move in with them?]
Years later, Jay sails to England to see his dying father. Grieving, he returns to Lisboa and stays at land for a while. He is restless until he meets JOANA, who resembles Laura.
He again does not dare to get too close and Jay flees to the sea. During his next journey [voyage], he considers all that has happened and finds that he does not want to lose Joana too and upon his return, he marries her.
Meanwhile Rui struggles with life aboard and Jay gives him a position at land, helping Joana managing his affairs. [Something tells me his affairs aren't the affairs he should be worried about.] He is restless as ever, and his daughter’s birth does not change that. When she dies shortly after, he runs away once again, leaving Rui behind to comfort Joana. Over the years Jay finds that Rui becomes more important to her than he. When war rises again, [Again? There was a war?] he desperately tries to find death in battle. Miguel takes the blow in his place and Jay survives, troubled that his friend died because of him. [At least now he can finally trust Miguel.]
Guiltily, he decides to leave so Joana can be happy with Rui. However, Tristão exposes Joana’s adultery and forces her and Rui to go into exile. [When you're leaving your wife with another man so they can be happy, adultery is pretty much assumed, and doesn't need to be exposed.] Jay realises he does not want to be alone anymore and accepts to stay close to those that care for him. [Who are we talking about? Joana and Rui?]
Twenty years after, a man knocks at his door. He tells about his mother, and Jay finds Laura did not abandon him after all. [It was never suggested that she abandoned him. He got her pregnant, then left Venice long enough for her to get married and give birth. If anyone was abandoned, it was Laura.] The boy was his son and finally, he is at peace. [His son is now in his thirties. He missed out on his son's entire life. And he's at peace? I'd be tormented by the knowledge that some other guy raised my son while I was off feeling bitter and trying to get killed.]
These short paragraphs give the feeling of an outline. A list of some things that happen. To some extent that's what a synopsis is, but if you want to tell a story, you don't want years to pass between every two sentences. And you need to tell the story with more specificity. Some of this is vague: Jay reflects on his life. He considers all that has happened. Some of it is repetitive: he stays at land for a while; Jay flees to the sea; he runs away once again; he decides to leave; he accepts to stay.
It's hard to focus on the most important plot line when the book covers 35+ years of the MC's life. Maybe the synopsis (if not the book) should start when Daniel meets Laura on a stopover in Venice.