chrome dog:
from the pic, looks like your options are a bit limited. One is to lay the rods on both benchs, and use some straps or something similar. I got a rubber stretch bungee type rod strap at bps for like $10 I think. It screws down so it would somewhat permanent and one of the ends would extend out into the seat/bench and be in the way to some extent as well. you could also bungee the rods up against the upper part of the side of the boat.
Could also mount some 1.5 - 2" pvc pipe on the support wall (either front or back side) of a bench in a vertical position, so the rods would stand up while in transit, and possibly while fishing if you placed them in the right spot. Wally world has the white ones in the boat parts sections, 'bout $5/ea, I used gray 1.5" pvc and plastic half circle clamps from HD to make mine, mounted them on the sidewall of the rod box so I could get my rods off the floor while fishing. I troll 99.9% of the time, so they are only in my way if I move to the back of the boat for something. Spent < $10 for pipe, clamps and screws.