Multiple bright strobes in a circular pattern over Puget Sound near Mebane Point navigational bouy.September 8, 2012, Performing a boat delivery five nautical miles north of Shilshole marina Seattle WA. The time was approximately 2100. I was traveling southbound at between 5 and 6 knots in a southerly breeze of 12 with a disturbed sea state. Clear skies very little ambient light.I was distracted by a flashing strobe type light from astern (North) looked back and discounted it as air traffic. About five minutes later took another look and lights were much closer and well defined. The strobes were flashing from my right to left (east to west) in the front of the craft. Continued to monitor the craft as it neared.As the craft passed over head I could determine that the flashes were distinct separate lights moving around the craft. The lights were bright enough for me completely lose my night vision. I could not make out any sound (please note that I was running a diesel engine at full throttle in building seas and breeze). I would approximate the altitude around 2000 to 3000 ft. Please note that I did not see any navigational lights or spots.The craft continued south, parallel to numerous commercial flights heading north prior to their east bound turn (out of Seatac). It passed at least three jets heading north and if this was odd they could not have missed the lights. I tracked the craft as it made an easterly turn over the shipping canal toward Lake Union. At this point I thought it might have been a strange lighting configuration on a sea plane which would land on lake union. Or a new lighting configuration on a plane heading for Boeing Field.My curiosity was piqued when the craft did not land in lake union or turn south to Boeing Field but instead turned north (probably over lake Washington) and continued that course until I lost it behind the rise (this is how I approximated the altitude) I was about two miles off shore and to lose it behind the hill the angle would not allow for much height.Strange occurrence and thought if you got other reports this might help to substantiate them. Times and heights are all approximated so use with a grain of salt. But I hit the Shilshole dock at 2200 so speed and time are pretty close.