From the looks in the pic, not sure the 90 degree angle is needed, just cut a piece of plastic into a rectangle and mount the plug with a water proof cap and be on your way. My TM plug has a cover that keeps water/ spray off the plug. Or, you could buy a small hatch to mount on a rectangular piece of plastic/ wood that fastens to the yellow dash, open the small hatch to acess the plug. I have one on my boat where the power cord come thru for the onboard charger. Lots of options, just how original does the owner want to be,.........