The construction arrangements came courtesy of Edward John Trelawny, whom I’ve mentioned several times here. As I said, he entered the Shelley circle early in 1822 via Bysshe’s cousin Thomas Medwin and quickly established himself—through some considerable flash and exaggeration—to be someone whom the Shelleys and the others enjoyed. He was full of adventure stories (some were sort of true), and he later published his own memoir—with Mary’s help (for which she received little of his gratitude)—Adventures of a Younger Son (1831). Even later, he would publish a self-serving memoir about his experiences with Shelley and Byron, called, frankly, Reflections on the Last Days of Shelley and Byron (1858). It, too, bore some resemblance to the truth.
Anyway, Trelawny was a robustly, romantically handsome man—a sort of Johnny-Depp-as-Pirate look—and Mary was taken with him. In Pisa, in February 1822, the group had agreed to Byron’s suggestion that they mount a production of Othello in Byron's Pisan mansion (with all of Pisa to be invited), and Trelawny, swarthy, was to play the Moor. Byron, we know, was good at suggesting things—like midnight ghost-story competitions—but his initial excitement sometimes faded with the dawn’s early light. Othello was one such project.
Still, the cast would have been fantastic. Byron as Iago (Medwin raved about his thespian skills), Mary as Desdemona, Edward Williams as Michael Cassio, Jane Williams as Emilia. Who wouldn’t pay to see that?
But all came to naught. Byron’s latest lover, Teresa Guiccioli, did not speak English, and, according to Medwin’s account, pouted, so Byron, after a few rehearsals, let the project die—just as he’d given up on his own ghost story back in 1816.
But if Byron suggested ghost stories and Shakespearean productions, it was Trelawny who fueled the fires of both Shelley and Byron to build their own boats for an idyllic summer by the sea.
 For two brief accounts of this, see William S Clair’s Trelawny: The Incurable Romancer (New York: Vanguard, 1977), 60; Leslie A. Marchand, Byron: A Biography, 3 vols. (New York: Alfred A. Knopf, 1957), 974–75.