I purchased both iSail and iHike apps this year and they are both TERRIFIC! They were easy to download and easy to used. I sailed both offshore and inside small harbors in New England and found the iSail app to be incredibly useful. I chartered a sailboat this year and the chartplotter mounted on the boat was old and lacked detail. I found the iSail app especially useful when going in and out of small harbors, which required knowing precisely where I was relative to the shallow areas, which I needed to stay away from. It was no problem holding my iphone while steering the boat. I still brought hard copy maps and used the boats compass, but this app greatly enhanced my ability to safely navigate, especially in tight places. iHike performed just as well when I went horseback riding on 80 miles of unmarked trails in Colorado in a area that was "off the grid" (I gave a separate review on the iHike site). Thanks for making such great apps!
i Sail GPS : NOAA Charts, v6.3.1