Passage to Fudaraku

One theme is religious piety. The whole story is centered on a voyage to Fudaraku. Fudaraku is an isle that is said to be the Pure Land of the deity of mercy, Kannon. However, the voyage almost always means certain death, which makes it even more divine to embark on. Those who take on the journey are revered by the people and are said to be more spiritually connected. However, it is not necessary to take on the voyage but it is expected by the people for the abbot to do it. Hence, Konko reluctantly undertakes this task. If he did not, he believed it would do injury to the faith. For him it wasn’t for his personal piety but it was for the sake of the religion itself.
Personally, it seems crazy to confine yourself in a box that is nailed tightly to the bottom of a boat, with little food and only an oil lamp while the boat drifts away in the sea. However, some of the characters earnestly believed they would reach Fudaraku to acquire a new life, an eternal life.
A contrasting theme is doubt. While the previous voyagers like Shokei and Bankei had high hopes for a new life, Konko seemed to be struggling with whether the island was real or not, whether it was worth the fatal endeavor and whether the ritual was necessary. Konko seemed doubtful of the island’s existence when he asked about its location. He didn’t seem to know how it looked. Others could see it but not once did he mention seeing it. Moreover, while people were constantly praising him, Konko was trying to “[cultivate] willingness to sail for Fudaraku (pg. 211).” In a way he is like the character Reverend Dimmesdale of the Scarlet Letter. They both grapple with their faith all the while people increasingly idolize them.
Throughout the story, from recalling the past to secluding himself, he seemed to dread the day he would drift off. Perhaps, his recollections of the past made him fear death. He recalled two young voyagers who were sick. It makes sense why they would endure the ritual. They were going to die so might as well die in a holy fashion. Konko, although 61, didn’t seem to be facing mortal illnesses. He also recalled Shokei’s surprising vision about the voyage; instead of reaching Fudaraku, Shokei will drown at sea. This disturbed Kanko. Furthermore, he was not content with an end like that. Unlike Konko, he didn’t reach enlighment. He simply chose to take on the voyage because he felt obligated by the fact that his predecessors did it. There was no holy meaning behind it.

Question: What is the meaning behind what Kanko wrote in the end of the story: "Should you seek Kannon, Believe not in Fudaraku. Shpuld you seek Fudaraku, Believe not in the sea."?