Total Newb Question

I am putting together an aquacopter (waterproof quad) for my scout troop to use in the Florida keys this summer, and I want to use the APM flight controller. But I won’t have access to the internet (or online maps) while out at sea. What flight modes require Droidplanner or internet to function? The most important to me are Alt Hold, Loiter, Circle, and Follow Me. I will not be using waypoints or trip planning, obviously. I will have a Galaxy Note 4.

You might want to consider using a Pixhawk instead of an APM, as the APM is no longer supported by new versions of the firmware. If you don’t want to fly any missions, you don’t actually need Droidplanner at all (except for Follow Me). For neither of the flight modes you describe, maps should be necessary. Everything but Follow Me can also be achieved with only a remote control.
For safety reasons, you should always have a remote control transmitter, to be able to take manual control in case of e.g. a GPS problem, and Copter will normally also refuse to arm without one.
The importance of being able to have full(!) manual control is illustrated e.g. in a mishap which I had recently (see … p-your-uav).

In my opinion I’d stick with the APM.
If you’re aquaquad has a possibility of not being 100% water tight and does go in the water, an APM is a lot cheaper to replace.

Besides, 3.2.1 which is the current stable release still works fine on it, it’s only from 3.3 onwards you would have to have a Pixhawk. If you’re happy to stick with the features of 3.2.1 you wouldn’t HAVE to upgrade either.

Thank you both.

Mark, that was my thought exactly. I’m trying to save some money, just in case it does get flooded.

Stefan, my next question is can I use Droidplanner for Follow Me without having internet or online maps available?

Also, I only want to fly my quad with a radio. I only plan on taking an Android device so that I can change settings or use certain flight modes, like Follow Me. After the trip this summer, when I have more time and internet access, I will explore the other possibilities.

I’d have to test to be 100% sure but it SHOULD work because follow me doesn’t use maps. It only uses the phone’s GPS.