Humminbird Cable tray- cover needed

Hi Guys,

I have a Helix 9 with the factory cable tray.  Since I'm in a kayak I take the head unit off when I have it in the truck and leave the tray hanging.  I did that with my Helix 7 when it was just 2 wires hanging.  Sometimes I would throw a baggie over the wires but that was more trouble than its worth.  I use dielectric grease on all of my plugs which keeps the water of the metal pretty well, but I'd like to put a better/more permanent cap on it for wet days and when I leave the boat in the truck and it rains overnight.  I've searched the web but can't find one.  Anyone know of a humminbird factory part that is a cable tray cover?  If not, I guess my best route will be a snap top plastic box with a cutout for wires but I don't want to go that route if I don't have to.

thanks

rick