you dont need the tray open to install a trim tube but i use a long drill bit and either 3/8 copper tubing or aluminum tubing.i have seen one of the water lines used as the trim tubes and the bilge eliminated and used for cooling. depending on where you need the tube. if you are putting a backflip nozzle setup on a SJ, its a waste of time. if you got the tray open, put another tube in there the same way the other tubes are in there.