is aware of the problem and should have an update on 6 April 2013.
I have the same problem and more on iPhone6 and 6s and on iPad.
Launch the App and press OK then nothing happens for about a minute
When It does launch it is agonizingly slow to populate the chart. as you move around or zoom in or out, it takes forever to re-populate or redraw the chart.
Hitting the route button crashes the HD version running on the iPad and freezes the iPhone 6s. The iPhone 6 doesn't crash but the other issues are there.
I also heard that the iPhone 6s 56GB model may have hardware
Now running iOS 9.3.1 on all three devices and still no joy. The only thing that the iOS update did was to solve the freezing issues that many of us have had with Apple Mail and Safari but it did not solve the freeze or crash issues with Navionics.
Very fustrating! I did speak to Navionics on 30 March 2016 and am told the next update should resolve all these issues.