Annie Hil wrote:
.Phones and GPS. I must have this wrong, but on occasion I've used the GPS on my phone, via Maps, and when it's lost its phone signal, it also loses its map. Could one trust it as an alternative to GPS offshore?
I have the Navionics App on my phone and have found it to be incredibly useful and reliable. I even use it in my work situation. Even a not expensive smart phone, provided it has a GPS receiver, (which most of them do), can become a chart plotter which may not have all the functions of a full blown marine chart plotter, but comes at a small fraction of the cost, considering that we already have the phone. You do need to download the charts onto the phone, and when using Google maps on a phone the maps need to be downloaded. I have used Google Maps in areas where there is no mobile reception. I did also once manage to get a longitude and latitude out of my phone GPS, but I cannot at present remember how I did that. I don't know that I would trust my phone as a method of offshore navigation without some kind of back-up such a good old reliable sextant. But I imagine that by now there are offshore sailors who have crossed oceans using their phone as a navigation tool.
I also have a very useful tide app on my phone which provides accurate tidal predictions for all of NZ including all secondary ports. And this was free, apart from the annoying banner of adverts which scrolls across the bottom of the screen, still there is no such thing as free lunch! Tidal predictions are also built into Navionics, but seem to only be for the current month whereas I often need to plan for a month or more in advance with regard to depth of water at different wharves we use.