Hi, I have an 1988 Catalina 30 which has been recently upgraded and refitted. Off and on during the last couple of days we are hearing a squealing noise aft,like a loose belt. It seems to come on when in gear over 1200 RPM's.The steering mechanism and gear and throttle cables were just serviced a couple of weeks ago, checked and everything seem OK. Mechanic on vacation until jan 5th. Any ideas? Thanks.