ThanksFuruno quality and support.
Furuno GP1870F - https://www.boemarine.com/products/...er-combo-w-525stid-600w-plastic-tm-transducer
$100 factory rebate - http://www.furunousa.com/Company/Furuno-Product-Rebates.aspx
C-Map 4D Chartography - https://www.boemarine.com/products/c-map-4d-na-d941-block-island-to-norfolk
See screen shots here: www.facebook.com/ifishmd or here: http://www.tidalfish.com/forums/showthread.php/479754-Viewing-dual-frequencies-with-your-fish-finder
Machine is excellent with target separation without expensive CHIRP transducers. Furuno digital signal processing allows for clear returns both on the wide cone low frequency 50kHz and narrow beam high frequency 200kHz. It also does great picking up water layers and bottom density changes. There is a reason most commercial users trust Furuno stuff. It is a little slow on the redraw for the plotter side but the charts are C-maps best. The sounder makes up for the slowness on the plotter side.
Here is from yesterday jigging fish to 31" showing excellent target separation.