ISTR something about boat batteries where you need certain amps draw for pounds of thrust for trolling. That determines whether a battery can do the job if it can do the amps for how long at how many amps.
The boat starting battery is no good for that apparently. Not sure if it said you can use the trolling batt for starting. Perhaps you can find info in that from Google.
EDIT
Here is that article--scroll down to where he talks about trolling motors and lbs of thrust etc.
https://www.deepcyclemarinebattery.com/reviews/upg-ub121000-deep-cycle-agm-battery.html