I have a lowrance HDS 5 with an Airmar B60 thru hull transducer as a fish finding unit and an older Lowrance LMS-332c as my chart plotter with the great lakes chip. I absolutely love my set up. The only issue with Lowrance products is that if you dump 1500 dollars into say an HDS-10 unit and after two years it goes bad, you’re up S%^$ creek without a paddle as they will not repair/replace their product after the 2 year window. You can send your broken unit in as a small rebate towards the purchase of a new/reconditioned unit. -Something to think about...

ReelTime is correct about the transducer. If I’m not mistaking, the B60 is 50 times more sensitive than the transducer you receive standard with your Lowrance unit.