For those interested in using a smart phone on a boat, especially an
iPhone, here's a great source of information from the
www.activecaptain.com web site. Jeff Siegal, author of the site, is
a very active boater himself and has done a lot of analysis. Jeff is
currently headed north for the summer on his trawler.

https://activecaptain.com/articles/m...ones/intro.php

If you register (free) with ActiveCaptain you get access to a wealth
of online charting and local knowledge. I use it frequently when we
are out cruising to get information anchorages, marinas and fuel
prices.