The elements of dead-reckoning are course and distance; the compass tells you the course steered, and a 'log' measures distance sailed. The common type of log is an electronic instrument that shows speed and distance run, much like the speedometer and milometer in a car. Overall, this product is loved http://productos-nauticos08549.bluxeblog.com/20519536/examine-este-informe-sobre-navigation-compass-for-boat