I have a problem with this quest. I can't seem to advance it. I'm doing it on my nightshade Jabstar.
I talked to Siobhan the smith but he doesn't have anything to say. It is possible that the first time he said something but i didn't see and now i can't see it anymore.
After reading up, i went to Meriach and whisper to her "Siobhan" and "I can hear the water calling" is several variations in /say and /whisper but nothing worked.

If anyone know what i'm missing i'd be most appreciative.

this is what my journal looks like:
https://imgur.com/Ode6i7Z

thanks in advance

EDIT: went back to Siobhan and said "Criostoin's Promise" to him. was so sure i had said that several time already to him.. and he gave me dialogue this time.. soo good news, no more help needed

When you talk to siobhan she tells you the exact phrase to recite to Meriach. I believe it is "I can still hear the waters calling"

I dont remember if it matters whether you whisper or say it, but spelling/plurals matters on the phrase.

Edit: just saw your edit :p