Hi Steve, Glad to know that there still are others out there who know how to run a slide rule. That was always a part of my navigator's tool kit. You can drop it, and it can get wet, but it always functions - and doesn't need AA batteries! GPS is really spoiling the world. It does so much, so elegantly, in such a small package! and it isn't sensitive to steel objects in it's vicinity...................! Years ago on our big boat, my compass was mounted on the bridge deck - between cockpit and companionway. If I was on the look out for traffic, buoys, light houses, or other aids to navigation I would stand at the front of the cockpit with the tiller between my legs and I could brace myself by holding the edges of the companionway. One time I was heading East on Long Island Sound, for Fisher's Island Sound, in the above described piloting position, when I noticed that I was way off my desired heading - but the compass course was correct. I changed heading (at this point it was all visual piloting in home waters) and when I got to Noank and moored the ship, my next question was, why was the compass so far off? Why did it give me a false reading? Some head scratching later, and several trips into the cabin and out again made me realize that as I went down the companionway, the compass heading changed. Why? I emptied my pockets. Still the same compass behavior. Then I had a flash of inspiration and grabbed the small magnet I always carried in my tool box, and checked the brass belt buckle on the webbed military belt I was using to hold up my pants. BINGO! The magnet stuck to "brass" belt buckle. So, my buckle, that I had bought at an Army / Navy store was not brass, as it appeared to be, but was brass plated steel. Buckle was removed and given a mighty heave into the ocean. Then I went back to the store and complained about their brass buckles being made of steel, and the problems that it caused. However, the clerk probably never was on a boat; and he didn't know what a compass was................................. So, I checked their buckle supply with my magnet, and finally bought a new one that was brass, and that passed the magnet test.................... .................but if I had been trying to find my way home in the fog...........................????? Connie M15 #400