Mark Ayers

I don’t think those will be battery selectors at all. rocker type switches are usually 15 amp or less load.
they are clearly aftermarket and probably replaced two of the original rocker switches in those locations.
Panel would indicate that they are fused. you can check the fuses and see what value they were fused at.
I’m going to guess this is power for some accessories, could be pumps, windless, etc… Or they could be main power on/off to the accessory panel itself.