Dr Nof is Missing 3 - Michael Brin, Homicide Detective Series, #7

The shape-shifting robot could be aboard the platinum spaceship. If it is, Detective Brin must find the ship and capture his fugitive. The only beings on Wacev, the Dooyen, fishermen, and fisherwomen, spend most of their time at sea. Because Brin doesn't know any of them, getting these strangers to help him find the platinum ship will be a challenge.