Sun Chaser is a Braavosi ship captained by Lady Elissa Farman, using the alias "Alys Westhill". The ship was constructed early during the reign of King Jaehaerys I Targaryen. Even before its construction, it had been the dream of Lady Elissa for many years.
The Sun Chaser was built for deep waters. Unlike most Braavosi ships, she is not oared. Instead, she is four-masted, with a lot of sail, a broader beam and a deeper hull.
In 54 AC, Lady Elissa Farman fled Dragonstone, taking with her three dragon eggs. She traveled to Pentos, and from there to Braavos, where she took on the name "Alys Westhill". Using that name, she was granted an audience with the Sealord of Braavos, who bought the three dragon eggs from her. Alys entrusted her new gold to the Iron Bank of Braavos and used it to pay for the construction of the Sun Chaser.
In 55 AC, the construction of the Sun Chaser was completed and Lady Alys began her journey. She stopped at Pentos to take on supplies, and next traveled to Tyrosh, where Lady Alys hired crossbowmen and sellswords as a defense for her travels through the pirate-infested Stepstones. Alys made it through the Stepstones unharmed, dismissed the men she had hired on Lys, and set sail for Oldtown. There, she arrived during the last days of autumn.
Alys desired to sail beyond "the sunset", to find lands between the far eastern shores of Essos and Ulthos that no one had found before. However, men willing to sail on such a mission were not easily found. With her gold, however, Alys was able to tempt men by paying higher wages than other captains did.
When word about Lady Alys reached the Hightower, Lord Donnel Hightower's grandsons, Eustace and Norman, were sent to question her and arrest her if need be. However, instead of carrying out their orders, the two men joined Alys's cause, pledging her their own ships, Lady Meredith and Autumn Moon. Afterwards, many sailors wished to join the crew of Lady Alys.
Lady Alys departed Oldtown on the Sun Chaser on the twenty-third day of the third moon of 56 AC. Although Lord Donnel Hightower, on the orders of King Jaehaerys I Targaryen, sent men after Lady Alys to capture her, the ships were unable to keep up with her and gave up one by one.
The Sun Chaser made her way down Whispering Sound. Alys was intend on sailing a southerly course, seeking warm blue waters and steady winds to bring her across the Sunset Sea. Once beyond the Arbor, Alys steered the Sun Chaser south by southwest. After twelve days without incident, the Sun Chaser and her companions were as far south as the Summer Islands, and farther west than any ship had been before, according to the calculations the men on the ship.
However, they had not seen a bird for four days, and soon after the winds disappeared. There was no breeze for almost a fortnight, and when the wind did finally return, the sky turned red as blood. Before morning the first storm began, followed by two more, each worse than the one that had gone before. Sun Chaser was separated from the other two ships by the storm, being driven westward, where the crew had spotted three small islands. Once the storm was past, Sun Chaser returned to fetch the Lady Meredith (Autumn Moon had gone down in the storm) and set sail again to the islands, which the crews named Aegon, Rhaenys, and Visenya. The two ships remained for more than a fortnight as the crew made repairs and replenished their stores.
When the two ships departed the islands, they parted ways. Alys Westhill sailed the Sun Chaser westward, and was never seen again as far as history knows. When Ser Corlys Velaryon sailed to Asshai-by-the-Shadow on the second of his nine great voyages, he spotted an old and much weathered ship which he believed was Sun Chaser.