Reddit reviews Demon Drums

Her first fantasy book was called Demon Drums. It's off Amazon for $4.

Carol took care with some aspects of Polynesian culture. In Hawai'i, an emphasis is placed on song and oral tradition as well as writing in native culture, so when Carol's characters want to cast a spell in her books, they don't point magic wands. They sing and gesture like dancers. They whisper into their hands and place it into the water for water magic, or they sing into the air for storm magic, or they hum a song while applying salve to make wounds heal better. I think it's actually cool the way she depicts it and her worldbuilding, and some other well-known authors have commented that Carol has been criminally ignored. Not even Hawai'i knew much about her, and they normally celebrate locals who make it big. I haven't read many authors who's attempted to branch outside of the "wand casts magic missile" version of magic in fantasy, probably because it's hard to do. I might copy her someday in that regard.

Full disclosure: my mother and some of my friends took her writing course. A couple were Hawaiian. They all said she was a hard teacher, had her favorites, and was apparently gunshy of anyone who had talent approaching hers, as many teachers do. She was hired because UH liked the prestige of hiring published authors as all colleges do. But she was more geared toward academia than writing, and I wasn't aware of anything she published while she was teaching. I understand she died a few years ago.

Carol Severance's Island Warrior trilogy has a tropical islands/reefs setting and plenty of focus on the ocean. The author spent many years living and working in Micronesia. First book is Demon Drums.