Found: Kids book scientist family telepathic dolphins

I borrowed this book from the lancaster county library system as a kid in the early 2000s. It was a large hardcover library bound book with lots of color illustrations. The illustrations were more realistic than cartoon. This fiction book was about a family whose parents were scientists and they had maybe 2-4 kids. They lived in this huge submarine with a kitchen, bedrooms, lab etc. They discovered this new species of dolphins that had these unique frills on their heads. I think the leader of the dolphin group was named Frill. As the family was studying the dolphins from inside the sub, pictures started flashing on the screen. They figured out the dolphins could communicate with these special frills on their heads - kinda an extention of sonar. The family found a way to communicate verbally with the dolphins (I think they invented something) and the dolphins helped them explore the ocean. I remember one of the kids hurt thier leg. Frill told them to put thier leg in the water and she swam up and used her sonar/telepathic thing to heal the leg.

The Secret Oceans by Betty Ballantine?

Openlibrary.org search frill dolphin
The secret oceans https://openlibrary.org/books/OL1085564M/The_secret_oceans

That's it! Oh thank you thank you guys! Your awesome!

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