There are many iphone apps that support tactics and navigation for sailboat regattas. TACTIMEM has the advantage of being easy to operate with one hand. Tacticians can take iphopne out of their pockets and take notes with one hand instead of notes. That is very important. Even if you have a high-performance app, if you can’t handle it easily, you will give up using it during a yacht race. It’s important that the minimum required functionality is easily accessible. Many tacticians take notes to complement their memories. Even a simple tool, notepad and pen, requires both hands. Hold the notepad in one hand and the pen in the other. Once you download TACTIMEM, go to the sea for sailing and record your boat heading. Many people tap the keypad with their thumb to enter a direction. Record a starboard tack or port tack if you are sailing upwind. The same is true for downwind sailing. The change of the wind direction can be grasped from the history. This is a feature of TACTIMEM. Other functions will be introduced later. Please try it first. Trial is free.