What is a good exploration fleet? (the size, composition ect)

[Das Pugenstien]

Im having trouble trying to discover Australia, it seems that most of my ships just die off imeadeatly due to attrition. P.S. im new

[Triggerhippy]

one single light ship is the best fleet.

The key is that a ship takes less attrittion passing through a known sea zone than they do discovering an unknown one. Keep a constant eye on what % the ship is at, as soon as it's starting to drop to about 90% bring it home,wait for it to repair back up to 100% and then push a little bit further (you'll get back to where you were with less attrittion because it's known allowing you to push on a bit more before you need to head home)

Always stick to coastal zones where ever possible, hold shift down to select your path if the auto pathing takes you accross deep sea zones.

[Xander Tyrann]

Similiar to what trigger said, but bring a few light ships to te nearest province you own, then detach a single ship and use that to explore, it depends how far away it is, i'd say bring it back at about 80% at first so you get an idea on how fast it will lose health on the return journey, then you can decide how far by yourself.
when it rejoins your fleet, merge it and then send out another ship with the explorer while the last one repairs.
this is the quickest way i know anyway.

you can shift click to add a move order onto the end of your last one, so you can tell it to go there and back, if you dont want to watch it, or are worried about forgetting it and it dieing of attrition (happened to me a few times).

Fleets have a chance of discovering nearby land provinces every time it goes past, so if you want to discover a certain provence, it might be a good idea to line up multiple move orders past it or set up a patrol.

[Das Pugenstien]

Thanks this has helped alot!

[HardyKnox]

Another non-obvious discovery I made. Look at the Trade perspective that shows Trade Centers and paths of commerce. These follow the prevailing winds, which also show up as small arrows. You'll sail much faster with the prevailing winds than against. So, Northeast America east along the GIUK gap along is with the wind. West Africa west to east Brazil is with the wind.