Because...
I mounted it up high so it can be seen better by both myself and other boaters. Sometimes anchor lights sitting directly on top of the mast are hard to see and I have a fairly wide mast head plate. Usually, when were going off in the dinghy during day light hours, but returning in the dark, I'll turn on the anchor light before we leave. In the day time, with it sitting on the mast head or very close to it, I can't see if the bulb is on. With it up high I can tell in broad day light that it's working without getting in the dinghy and going 100 yards away. It also gets it out of the way of the wind instrument for unobstructed 360 vis..Overkill yes but I like to be able to see it during daylight hours from my cockpit or deck for a quick check.. As we know incandescent anchor and mast head lights often get burned out due to mast vibrations so it's nice to be able to see it before it gets dark..The white board is Starboard and is mounted into the three holes that were already there from an old light. It allowed me to not re-drill my mast head. There are six screws. Three mounting the Starbord to the mast head using the old screw hole pattern and three offset from those mounting the light to the Starboard.. It also serves as a break between the aluminum and stainless for corrosion issues....