I have a water tight box where I plan to store my wallet, phone, keys etc. so it needs to also have a spot to keep that close and handy. The design I ended up with has a frame to fit the water tight box and then on top of that another box to hold the tackle containers. I'll attach rod holders to the side of the top box.
The bottom frame around the water tight box.
The top box to hold the tackle containers, sitting on a top that will house the rod holders.
Marking out the box joints for the top box.
Cutting the joins.
Chiseling out the waste.
Trial fitting before gluing.
Here the lid has been trimmed to size. The side flaps are where the rod holders will be located.
All glued up. The lid is temporarily screwed on, whilst I figured out how best to attach the rod holders.
This is where the PVC rod holders will go. I'll add some extra layers of marine ply under the flaps to strengthen then holders.
On top of this box that holds the tackle containers will be a lid made out of a plastic chopping board. This will double as a bait board and I'll mount a bait knife somewhere handy.