I am using the Lowrance x50ds I got from my Hobie dealer and the mounting foam transducer pad 72021011 (about $3) and Marine Goop (about $7) mounting it just aft of the sail mast well in my Revolution. I am usually in the ocean where it can get pretty rough at times and have been very pleased with the performance. I did not use the Hobie kit though but purchased a 7ah sealed battery which I recharge with a solar panel (could be easily charged with a small trickle charger). I recharge weekly whether I use it daily or just once and never ran it down. I already had the solar panel ( 5watt) so this was by far the least expensive option for me and very easy also. I just use a velcro strap from Home Depot to hold the battery to the mast well and use a little
Superlube (a Teflon lube, could use substitute) on the terminals to eliminate corrosion. The main unit is mounted on a RAM 5 spot mount along with my GPS, a rodholder and marine VHF or multi band ham radio (may eventually add an mount so I can mount both since I have another hole in the 5 spot left).
Fishing, freediving and SCUBA diving off my Revolution when not just pedaling or sailing