2002 Cobalt 226 (5.7 Volvo) conks out on the lake with no warning

Was on the lake today. My 2002 226 with Volvo 5.7 power started normally, and then idled out of the bay for about 2 minutes. I then took it up to 3,000 RPM to plane out and it went dead instantly. All electrical other than the blower and trim showed no signs of life. No click of the starter, nothing. The batteries are new this year, all connections look fine. Is there a main fuse on this boat or fusible link? If yes, anyone know where it is? Lucky a good Samaritan towed us back to our island, as it was pretty windy today. Opinions and theories greatly appreciated. Thanks