You need two deep cycles wired in series for 24 to run the TM, separate from the engine starting battery. You can take 12V off of that bank. You'll need a three bank charger since you will essentially be charging three separate batteries.
2015 Seaark 1872 MV CC Etec-90
Two Helix 12 CHIRP SI's, , MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
Bitter Gun Owner