when you take the coral tunnels to get to the springs, look to the left near the edge of the rocks, there are lots of crabs in this area,look on your maps, the circle area is the tunnel that will take you to the back area and you will find 2 thunder eggs,(Ship Wreck and Nest Egg), a cog and a bilby.

It is near the quick sand area first you find the biggest water hole from where you swim into the quicksand area then you dive in and face the quicksand go down and you'll see a hole swim throught the hole and you found the Ship wreck

look on your map. by the quicksand there are 4 circles. go to the circle on the far left and dive in. there will be a tunnel. go through it and you will find another area with a cog, a bilby, the nest egg challenge and the ship wreck challenge.

you go in the hole when you come out on the other side of the ship there is a hole under
water on the side of the ship its not big enough to swim in but theres a button use your
aquarang to hit the button on the other side a door opens swim in and there it is