Interstate makes a group 24 with 1000 cranking amps. The dealer rigged my last boat with one when new and I constantly had issues with running low/out of power. I moved up to a group 27 flooded cell Deka and had no issues. Eventually went with the Duracell grp31 AGM from Sams Club for a cranking/electronics battery after seeing tons of positive reviews and Sams running a killer sale on them. Same battery is going strong with a different owner.