I just got a note from Captain Richard Rodriguez over at Bitter End. This concerns a specific model of Class A AIS transceiver…not something most recreational boaters are likely to have aboard. But this certainly is a strange phenomenon.

Remember, "The prudent mariner will not rely solely on any single aid to navigation."

Here’s the report from today’s Notice to Mariners:
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Reports have been verified that some SAAB R3-AIS Transponders, when combined with older GPS receiver, have stopped working while GPS Satellite PRN32 is in view. Vessels affected are reported being invisible to other AIS equipped in addition to some AIS equipped shore stations. It has been reported vessels equipped with the SAAB R3-AIS Transponders continue to receive AIS information from other AIS equipped vessels.

All vessels are advised to check the proper operation of their AIS and GPS equipment. GPS problems should be reported to the USCG Navigation Center at WWW.NAVCEN.USCG.GOV/GPS/USERINPUTGPS.HTM or contact the USCG Navigation Information Service at (703) 313-5900.