ACR MLG ACFT EXPERIENCED A TCASII ALERT WARNING ON FINAL WHICH APPARENTLY CAME FROM A BOAT IN THE HARBOR.

Narrative

FALSE TCASII RA AT 500 FT AGL. SHORT FINAL AT BOSTON LOGAN ARPT. VISUAL APCH 4L. SINCE THIS WAS OBVIOUSLY A FALSE INDICATION WE DID NOT INITIATE A GAR. NORMAL LNDG MADE. CALLED LOGAN TWR AREA MGR TO DISCUSS TCASII ADVISORY. HE SAID HE WOULD MAKE RPT TO WASHINGTON; DC. POSSIBLE CONTRIBUTING FACTOR WAS ANOTHER ACFT LNDG 4R SIDE BY SIDE. HOWEVER; TCASII SHOWED THAT ACFT AS A TA. POSSIBLE BOAT IN HARBOR SET TCASII OFF. ONLY 1 SMALL (APPROX 40 FT) DOCKED BOAT WAS NOTED BY US. TWR SAID THEY SAW NO BOATS IN HARBOR. NO OTHER EXPLANATION FOR TCASII ADVISORY. SUPPLEMENTAL INFO FROM ACN 205793: IT WAS OBVIOUS TO BOTH OF US THAT THIS WAS A FALSE RA. THE TWR WAS QUESTIONED ABOUT SHIPS IN THE HARBOR AND SAID THERE WERE NONE. I'M WRITING THIS BECAUSE COMPANY POLICY IS TO RESPOND TO EVERY RA. I BELIEVE OUR COURSE OF ACTION CORRECT; BUT A FORMAL RPT WILL PROBABLY NEVER BE FILED DUE TO THE VIOLATION OF THAT POLICY. IT'S A SAD STATE OF AFFAIRS WHEN A CAPT CANNOT RPT INCIDENTS SUCH AS THIS WITHOUT FEAR OF FAA ENFORCEMENT ACTION. I'M ALSO VERY CONCERNED THAT THE FAA IS GOING AHEAD WITH TCASII INSTALLATION WITH SOFTWARE THAT DOES THIS. A GAR FROM THIS SITUATION WITH A LARGE CHANGE IN PITCH ATTITUDE; REQUIRES A LOT OF PLT SKILL; SCARES THE PAX; AND CAUSES POTENTIAL TFC PROBLEMS FOR TWR. ALL OF WHICH CAN BE DONE OK ON A VFR DAY. BUT WHAT IF THIS WERE 4R; IFR. BOTTOM LINE: SHIP OR BOATS OF ANY KIND SHOULD BE PROHIBITED FROM STOPPING OR TYING UP AT THE END OF ANY RWY AT BOS OR ANYWHERE ELSE.