USS RIGEL (AD-13); later (AR-11)
RIGEL (pronounced Rye' jell - but you probably already knew that) was originally commissioned as a destroyer tender in 1921. Refitted and redesignated as a repair ship in April 1941, she was at Pearl Harbor during the attack on 7 December (which, of course, was before your father-in-law's time, but there's more).
No vets association so far as I can determine but you might contact Pearl Harbor Survivors Association (you can e-mail via their website at < http://members.aol.com/phsasecy97/http://members.aol.com/phsasecy97/ > - click on address to go there).
Brief ship's history at < http://www.hazegray.org/danfs/auxil/ad13.htmhttp://www.hazegray.org/danfs/auxil/ad13.htm >