First I created a 32 feet long drill-set, since I didn not know how far down the foam reaches inside the mast. To create this drill, I used a 48" long “⅜” flexible drill” from Harbor Fteight as drill-head and added 7 each 3/16" steel rods (48" long) from Home Depot.On both ends of these rods I cut10-24 treads at about 1" long. Then I made 7 couplers out of 3/8" aluminum-rod from Home Depot and drilled and cut inside treads. The whole set screws together as yougo and there are only 48" of notsupported drill at any time. To start the actual installation, I removed the bottom piece of the mastand removed the rivets, holding the mast-cap. After completing the install, I closed the old rivet-holes with electrical tape and drilled and tapped new holes for 8-32 screws. The actual drilling through the mast went really smooth since there are only about 12-15 feet of foam in the top portion of the mast.Once the drill reached the bottom of the mast, I attached the wires and an additional pull-cord, for future needs,with electrical tape and pulled them through to the top. After connecting and mounting the new LED anchor light I replaced the old motoring light bulb as well with a replacement LED bulb. I use reversed polarity to switch between the anchor light and the motoring light. To be save, I protected both LED-assemblies with blocking diodes (3A, at Radio Shack) against reversed current and wired everything at the bottom of the mast, using the original 2-pin deck connector.