Sounds like typical bass fishing patterns in a typical average to smaller sized TX tournament quality bass boat on sometimes windy Texas full tournament days. Watches batteries and wants full battey life so sizes batteries to never discharge them more than 50% before recharging:
If your 24V TM is a modern digital type 70lb, and is rated at pulling 40amps on high, you will likely most often run it about mid high trolling speed, so you may average using 30 amps when it is ON.
If you are trolling/pausing and fishing/trolling a moment and also sometimes are tying on lures, hopefully landing fish to two during the day, you may actually be on the TM power only an average of 20% or 12 sec/min during an an 8 hour day.
Two batteries each with an RC of 210 minutes used on a TM drawing 30amps at 24V being used 12 seconds of each minute would reach 50% discharge and need recharging after 7 hours, 15 min.
25amps RC/30amps =.833
0.833 X 210minutes X 50%discharge limit =87 min
87 min X 60second/12seconds =435minutes
435min = 7 hours 15 minutes.
Consider two deep cycle marine batteries each with a Reserve Capacity (RC) of about 210 minutes.....typical size 29M. Ignore the CCA and MCA ratings.