was sailing south in Costa Rica in the days of paper charts, dead reckoning and sextons when I had to pull into "Punta of your anus" for some work on my transmission. My paper chart ended about half way up into the Gulf of Necoya and didn't show the river. You had to sail up the river to the town back then and there was no marinas. I called on the VHF and got reply and was told to "head up the river and take the white ball on my starboard side and come up to the "yacht club". The white ball turned out to be a 50 liter jug which I failed to see and ended up going way up towards the end of the estuary. I realized my mistake and turned around heading back towards the gulf until I saw the "ball". I set my depth sounder for 10 feet and started heading for it and turn back to port every time my depth sounder went off. I'd keep towards port until the alarm cleared and finely made it to the ball and headed up the river. I got as far up as I dared but not all the way to the "club" and dropped the anchor in front of an old saw mill. A dutch couple, Edger and Anna, had converted it into a cruisers hang out and it was fine with us. We went ashore in the after noon and returned after dusk. The next morning we found out that we had arrived on one of the highest tides of the year and that there was a storm in the mountains that flooded the river and estuary. The tide was now down to normal and we figured out that we had sailed over a cow pasture complete with barbed wire fence and broken down tractor. Let's have a big hand for the guy who invented GPS!