Sisters travel to a new realm accidently [s]

[Ac]

This book is for young adults and is about two sisters, it starts off and one walks too far into the sea and the other goes in to get her and they are both washed away. One gets hauled up into a sailing ship while the other is on an island or something. One is blind.
The series is old but not complete. The only other bit I remember is that it ends with the blind one going to an island that only she can go to.
any ideas?

[Ac]

I almost forgot, the blind one plays music. before they were washed away the sister would write music (the blind one) and sell it to artists.
(probably not helpful but you never know)

[Ann aka Iftcan]

How long ago did you read this?

[Ac]

It was 4 years ago, but my sisters read it probably 5 years before that. The series is incomplete, I think only 1,2 perhaps 3 is out.

[Ac]

Thanks everyone, but I found it. It is Isobelle Carmody's The Legendsong series:
Darkfall (1997)
Darksong (2002)