I was at san clemete state beach with 3 friends around 12 midnight having a bonfire along a small canyon running from hills down to the beach. the night was quiet when suddenly a loud loud sound occured . it resembled a noise like a slowly revolving large centrifugal engine of sorts i guess i would say to describe it when i first heard it, over the next 10 to 15 seconds the speed of the revolutions increase in speed exponentially until the sound was a high pitched whirring sound. then suddenly the noise dissapeared. all 4 o us were running toward the beach as this was happening and by the time we reaches the beach thats when the noise was gone. i would say the noise was louder than any craft i have heard before taking off. it seemed to have come out of the ocean and take off into the distance at incredible speed. although i only could tell this by sound.