Sounds like it should work well and be sealed from water intrusion too.

The correct standard transducer for the 898c Si units is the XHS-9-HDSi-180-T, but the one for the trolling motor is the XTM-9-HDSi-180-T (same transducer just different mounting hardware).

That 8,000 Watt transducer is for very deep water and is only for the conventional 2D sonar – not something that most crappie fishermen would use.