Cache is located approximately in the middle of the island and contain pencils and logbook. Cache is small green box, hidden at the stone barrow - see photo hint, It is located near the ruin of some old house. I recommend to have a swimming or other shoes because you have to go a short walk to the cache. You can see photo hint and GPS isn't necessary - specially for swimmer 😉.
Terrain 4 is if you will swimm about 400 metres to the island from Primošten beach. You can also use sea taxi, rent paddle boat, kayak, boat , jet ski or maybe swimm on air mattress, but in this case is easier terrain 😉