Raymarine DSM-30 or 300?

[Roy M]

Hi, I'm in the final stages of decisionmaking (about to haulout and cut holes) and trying to make a final decision on which of two fishfinder sonars to install. My boat uses a full E-series bank of electronics from Raymarine, integrated in one cockpit display and the laptop in the nav station.

The issue revolves simply around which of two sonars to use:
DSM-30 uses 12 volts, a smaller transducer getting signals from a couple thousand feet down, and includes a speedo/temp unit in the transducer.

DSM-300 uses 12-24 volts, has a much more powerful transducer, which is understandably larger, has no speedo/temp option, and reaches down about 5000 feet.

I'm leaning heavily toward the simpler, cheaper version, though the additional depth seems like a cool feature for coastal navigation in deep waters. Anyone have actual experience with these units?

My boat is a planing hull Searunner tri, 40 feet long, and I will be simultaneously installing the Interphase Sonar Engine blackbox scanning sonar. In operation, the Interphase will operate at 200k, while the Raymarine operates at 50k. When I actually need to monitor the deepest readings, I will switch off the Interphase and switch the Raymarine to 200k. Engineers for both companies assure me that this is an ideal combination for use of the two products in tandem, and it provides me with depth sounder redundancy, which is pretty nice.