No need for a bracket. I just used a 3/16" OD x 3' long nylon line as a leash connected via a snap shackle to another line I run across the deck, in front of my seat.
I store my hawg trough on the R/H side of the deck , going forward to the rod tubes.
When I need to use the HG, I pick it up, lay the fish on it and don't worry about losing it with the leash attached. More than once I have let the HT hang over the side while I attend to more pressing issues.....like getting the fish on my stringer if I decide to keep it or quickly releasing it.......I normally release rainbow trout that do not measure 18" minimum.
This photo shows my white NWKA hawg trough on the r/h side of the deck.....it does not get in the way and is quickly available when needed.
And the leash is still connected in this photo on shore.