I planed the bottom of the board and for my first time I was quite surprised at how well it turned out, but on the deck I tried the planer when I reached the top quarter of the board the curve of the board lifted the center of the planer and nothing cut.
Due to the nose rocker curve in the deck of a surfboard planer blades cannot easily get to the foam in that area. A trick is to turn the planer on an angle so the barrel is more parallel to the stringer in the nose curve area. It's not easy and most beginners just use a G-rasp or tigershark paper on a hard block to shape that area.