I have heard the turine boats around the docks make a noise like a am radio losing tune... it is in this video at around 2:40 and throughout the rest of the video

http://www.youtube.com/watch?v=KQdY_...eature=related


also in the powerboat article they were talking about the throttle set up in copelands phenomenon...and it lead me to believe they had to do some engineering to get it down from 12 levers, and they indicited a seperate throttle for n1 and n2......

what is n1 and n2 and do they require sperate throttles and if so why?

thanks...