On his first day, Mr. Piailug took stones from the garden and made a map of the stars on the ground, Mr. Thompson said. Slowly, he learned to pay attention to ocean currents and read the weather from the color of the light at dawn.

Since then, he has guided the canoe on six major voyages totaling more than 140,000 nautical miles, inspiring a revival of canoe building and wayfinding. According to the Polynesian Voyaging Society, there are now 25 deep-sea voyaging canoes in the Pacific, and more than 2,000 active voyagers from 11 Pacific Island nations.

Mr. Thompson spent six years repairing Hokule’a and training 350 crew members in preparation for the canoe’s global voyage. (At any given time, Hokule’a has 11 to 13 crew members aboard who rotate in and out every four to six weeks.) In particular, he focused on passing on the core concepts of traditional wayfinding to younger crew members who he believes will be committed to sharing them with the next generation.

One of those is Jenna Ishii, a 29-year-old apprentice navigator who also works as an education coordinator for the Polynesian Voyaging Society. On training sails, she said, Mr. Thompson teaches apprentices skills like how to stand and sleep simultaneously — “he will stand up and put his hands on the railing with his elbows locked so that he can sleep for a few minutes at a time,” she said — and how to observe the ocean and the sky for cues.

“Nainoa says that a navigator will make over 1,000 observations a day, and make two key decisions — at sunrise and sunset — about how far you have gone and where to go next,” Ms. Ishii said. This includes plotting a course that will ensure the canoe travels upwind for most of the journey before switching to downwind to reach its destination, avoiding what is known as tacking — sailing back and forth against the wind.

While the crew aboard Hokule’a will, for the most part, use wayfinding techniques, the canoe is equipped with modern instruments in case of emergencies, and to navigate around more dangerous straits and channels, like the Mozambique Channel and the Cape of Good Hope in South Africa.

“If we can navigate without them, we will,” Ms. Ishii said. “But if the weather compromises us, or it becomes an issue of speed, we will use instruments.”