I hate cross posting so I won't repeat what I posted in the general section. I probably should just have posted here as this is a racing app. I will just explain that this app was developed by racing and I didn't quit until it actually got me to the starting line on time, going fast. As readers of L-36.com may know, I tried several of the existing apps and found that they either did not really help you get to the line on time, or they were impossible to read because of low contrast displays. Some of them are very pretty and StartLine has all the beauty of a knot meter but it works. StartLine (search for that on the Google Play store -- one word) uses large high contrast lettering and all the programs navigation is done off these large letters. You don't have to hunt for the small phone nav buttons that are impossible to see in the cockpit.
While mainly developed to get fast starts, it also has a flexible waypoint capability that is easy to use and displays the relative direction to the next mark, the time to that mark (compensated for tacking by the way) as well as speed and heading.
I will also add that a lot of work went into the accuracy of the GPS system. Readings are once a second as that gives the brain time to process the readings but if you ping one end of the line, that location is interpolated between GPS events to the milli second. There is also velocity compensation of location so that the delays and processing time don't end up telling you where you were rather than where you are.
It is a stand alone GPS based application and if that is what you are looking for, I think you will like it.
Check out a complete users guide at http://L-36.com and hit the Android StartLine tab.