The great-grandfather of the Chida, Reb Avraham Azulay zy'a, author of Chesed l'Avraham, lived in Chevron, Eretz Yisrael. Once, as he was traveling to chutz l'aretz to collect money for the poor in Eretz Yisrael, there was a great storm, and it seemed that the ship would capsize. Reb Avraham made a kabbalah that if Hashem saves him and the storm calms down, he will tell people about the miracle that happened to him. He will speak about this miracle every day of his life. Immediately after he made this kabbalah, the storm subsided. In memory of the miracle, he signed his name as a picture of a ship to praise Hashem and to publicize the miracle.
Indeed, the Chesed l'Avraham taught that when one is in a tzarah, he should accept upon himself to say Nishmas in front of ten people when Hashem will save him. Many people have practiced this segulah and found it helpful and accurate (see Kaf HaChaim 281:8).
The Midrash (Shochar Tov 70) writes, "The Yidden were redeemed solely because they talked about Hashem's kindness. Dovid said, 'If so, I will also discuss Hashem's kindness. Therefore, it states להזכיר לדוד למנצח להצילני אלוקים, 'For the conductor; of Dovid, to make mention. Hashem to save me...'"
