A Ship in the Harbor by Mary Heron Dyer

Meg Blake's life is at a crossroads: her 17-year marriage is no longer tenable since she's come out as a lesbian, her work within the Catholic Church has lost its meaning, and her first relationship with a woman has come to an end. In an effort to gain control over her life, she leaves her family and moves to the Oregon coast.

There she meets Jody, a young marine biologist, at a women's gathering and is immediately captivated by her warmth and vibrancy. That evening, Jody and her lover Susan are involved in a suspicious car accident in which Susan drowns. The police suspect Jody. But Meg knows they're wrong and teams up with Jody to expose the real murderer.