I wasn't real clear on the hopper.
I've already mounted the hopper, it's alloy and it has doors (like trap doors), all the builder would need to do is figure out how to operate the doors by the servo inside the hull (I guess by servo arms), the doors fall, or open, whatever... and the feed falls into the water. The hopper looks just like the one in the finished version.... I've attached it to the deck already with screws. I haven't taken a photo since I've done that.

That's quite more then I had in mind