Estimating Distance From Shore

June 18, 2015

Question: I have a question that’s a bit off the wall. If I am on the water, how can I accurately estimate when I am around one mile from shore? Assuming great visibility, if I am on a boat and standing 10-20 feet above sea level and I have 8x binoculars, how can I tell if I am less than or more than one mile from shore? I seem to recall someone saying to estimate half to horizon and then half of that. Does that sound correct? (Craig N.)

Answer: Because of swell conditions, it would be nearly impossible to estimate the distance from shore in the method you describe. The most reliable method would be to use a GPS or plotter. You can also use a compass pointed toward known locations on land and triangulate your position fairly accurately on a chart.