AN SMA HAD A PARTIAL ENG FAILURE.

Narrative

WE HAD TAKEN OFF FROM BAYPORT; NY (23N) AND HAD TURNED E FLYING ALONG THE LONG ISLAND SHORELINE; BELOW THE FLOOR OF THE CLASS C AIRSPACE. AT ABOUT 3 NM SE OF THE ARPT; WE EXPERIENCED A SIGNIFICANT DROP IN RPM AND SIMULTANEOUS DROP IN OIL PRESSURE BELOW RED LINE. WE TURNED IMMEDIATELY TOWARD THE ARPT AND CLBED TO 1000 FT; TRADING EXCESS AIRSPD FOR ALT. THE ENG STILL PRODUCED ENOUGH PWR TO MAINTAIN ALT. HAD THE ENG QUIT AT THIS TIME; WE PLANNED TO DITCH IN THE WATER ALONG THE SHORE OR IN A MARSH BORDERING THE SHORE. WE INVOKED OUR AUTH AS PIC IN AN INFLT EMER AND HEADED INLAND TOWARD THE ARPT AT 1000 FT; EVEN THOUGH 1000 FT PUT US IN THE CLASS C AIRSPACE ABOVE THE BAYPORT CUTOUT. BUT 1000 FT ALSO PUT US WITHIN GLIDING DISTANCE OF THE ARPT OR THE SHORE AT ALL TIMES. THERE WAS NO PLACE TO LAND SAFELY BTWN THE SHORE AND THE ARPT. TO FLY AT A LEGAL (AND LOWER) ALT WOULD HAVE BEEN RECKLESS. THE ENG CONTINUED TO PRODUCE PARTIAL PWR AND WE LANDED SAFELY AT BAYPORT. WE WERE SQUAWKING 1200; MODE C. WE DID NOT CONTACT ATC. IT SHOULD BE NOTED THAT THE 700 FT FLOOR OF THE CLASS C AIRSPACE IN THE BAYPORT CUTOUT DOES NOT ALLOW A SAFE TRANSITION ALT FROM THE SHORE TO BAYPORT; SHOULD THE ENG QUIT. SUPPLEMENTAL INFO FROM ACN 271384: THE LINEAR DISTANCE FROM THE CTR OF THE ARPT (23N) TO THE S SHORE OF LONG ISLAND IS APPROX 2.5 NM. PERFORMING A STRAIGHT-IN LNDG TO RWY 36 PLACES THE ACFT AT AN ALT OF 600 FT MSL AT A DISTANCE OF 2.5 NM FROM THE RWY. I SUSPECT THIS IS BEYOND THE PWR OFF GLIDING RANGE OF MOST OF THE ACFT USING 23N.