[Closed] Offline android phone for cycling navigation?

Hello,
I am too cheapskate to buy something like a Garmin 810 so I am wondering if I can use an old android phone (e.g. Galaxy S3) without a data connection to navigate when cycling?

I'm going to test out maps.me over the next few days but I am wondering if anybody else has any good experiences of any other apps for offline route planning/navigations (I will be using it in Singapore BTW).

Also, I am finding it a little hard to find a good waterproof phone case to mount on handlebars, any suggestions? I am currently using a Lidl one which is ok, but it rattles around a fair bit when travelling at speed and probably wont be fully waterproof in a downpour (in Singapore when it rains, it torrents).