positive to positive. Thinking about doing this myself. Batteries in my CC are not an easy swap. On my Ranger I could leave batteries in place and just run motor cables to other battery.

I have one of these, not the same exact model, but same thing...
I carry it with me all the time in the truck or boat... YOu can use it to charge/recharge a phone and jump a battery if needed... small and hand held/portable..

https://www.amazon.com/Beatit-18000mAh-P...words=jump+boxs

Make a cable long enough to permanently connect to one of the trolling motor batteries and your cranking battery, positive to positive. Make the second cable attach to the negative terminal of the cranking battery, make it long enough to attach to the trolling motor battery negative terminal but just wire tie it to the cable that is already on the battery, you can wrap some electrical tape on the terminal end if your concerned about the cable touching something (although it won't do anything bad even if it did). Then if you ever need to, you can loosen the negative terminal connection on the trolling motor battery and attach the cable. No need to disconnect the trolling battery's existing cable connections. Connecting the cable will not effect the use of the trolling motor. No need to disconnect it after starting the big motor, just undo the cable after you get home.