Charts and GPS help sailors stay out of harm’s way. But for navigation in those more remote destinations that may not be well-charted, relatively small and affordable forward-looking sonar is added security. Longtime cruising sailors Andy O’Grady and Ulla Norlander sea-trialed Interphase’s new SE-200 Sonar Engine aboard their 42-foot sailboat Balaena. They used the sounding equipment primarily in Brazil’s muddy rias and shallow rivers. After six months of forward-looking sonar tests, O’Grady and Norlander found that getting the most out of the device had a big learning curve. Sailors need to master the art of reading the sonar, adjusting the equipment, and determining false echoes. Common problems testers had with…