Ferry loading has to consider where you are getting off and what's already loaded. I've had to back onto a ferry, U turn and backup inside a ferry.
Time is important and you won't be getting out to check where you're backing. Any you can't always see side clearance when going forward.
Few vehicles have the restricted ground clearance and hence ferry ramp angle changes than my present MH. I have a 13' rear overhang from the drive axle which is much more significant than the tag axle. Monaco reduced the ground clearance and increased the inside height.
I always check/signal to the ferry crew about my concerns but they have to date been on top of that. They do have blocks, etc should that be necessary at say lower tides.