Woman at sea in yacht (7)
I believe the answer is:
cynthia
'woman' is the definition.
(I know that Cynthia is a female given name)
'at sea in yacht' is the wordplay.
'at sea' indicates anagramming the letters.
'in'+'yacht'='inyacht'
'inyacht' anagrammed gives 'CYNTHIA'.
(Other definitions for cynthia that I've seen before include "Woman" , "Girl" , "Girl's name" .)