[hteas]

Most of my diving when spearfishing is without a rope, and in low visibility. I fairly regularly dive down and discover that the bottom is sloping very steeply. When I turn upright I discover that the steep slope was me, not the bottom : o
On a related note, diving the ropes at Hounaunau in Kona I discovered myself swimming horizontally down the rope. While followint the rope I could see the bottom way down there, and look back between my fins at the surface, but the sensastion was absolutely that I was swimming horizontally along a vertical rope.
I guess Eric F is right, but I sure haven't learned the secret yet.
Howard