You are downloading the Seapilot APPX file v220.127.116.11 for Windows Phone. Seapilot is a free and useful Utilities & Tools app: Professional marine navigation used to require an expensive GPS plotter. Now, same technology used in merchant shipping is available for Windows. ... You can now download the offline APPX file to install & try it.
Download Locations for Seapilot 18.104.22.168 APPX file
Important Notice: Now Due To Unspecified Limitations, You Can Not Use The Offline APPX File To Install It Any More.
To try to install it manually from an SD card, you should choose one of the server location above to get the offline Seapilot APPX file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.