We just completed our second extended cruise with Belle-Vie using a Garmin 178C map plotter sounder. Our 700 mile cruise several seasons ago was a dream with the 178C the fam got me for my birthday in 2005. I purchased a 32meg data card, which holds two chart regions (250 charts) that covers Puget Sound to the north end of Vancouver Island inside and outside.

Belle-Vie has a 1991 Autohelm ST7000 course computer with a ST6000 head. I wired (22AWG stranded copper communications wire, black and blue) the Garmin data out lead to the head data in lead NMEA interface port. The two systems use different NMEA versions, but Im happy with the results. Just make sure that you connect the Garmin data in lead (blue) and head data out lead (black) to ground. Otherwise, it will not work. It took alot of Raymarine and Garmin help desk time to figure it out.

I still carry paper charts and a Garmin 38 hand held GPS just in case. The 178C is right on, easy to use and loaded with chart data. The unit has saved our fanny more than once. I mounted it on top of the instrument pod, right above the 6000 head. Running the wires through the SS pedestal guard conduit was a chore. The external antenna is mounted on the stern rail, starboard side and the shoot through the hull sounder transducer is located on the port side of the shaft strut inside the aft cabin beneath the sole board.

The sounder works great. Water temperature, fish display, type of bottom, tide state, etc. Very happy with the systems performance, Everything at your finger tips.