If the boat is pushing, the net gets to the leaves first. If the propeller finds the leaves before the net, it will end badly.
Best bet is probably something substantial to push the net on its frame, but send it out with a line attached. That way, when the amount of push gets to be too much, you have a way of recovering manually.
The amount of energy required to lift a netful of soggy leaves will far outweigh any benefit gained from draining them, which will probably not happen until well after you get it back to the bank. Keep things simple. i don't see leaves being lifted - I do foresee the net and boom being dragged down. A shorter span might work better - less to push.