LordFess

I am exploring the last jungle area in the Peruvian Jungle that you come to before you get to the Village. There is a campsite there near a crash site with a lot of crates lying on the ground next to a small lake where part of a plane is submerged under water. When you come near the crates near the water's edge there is a beeping sound coming from somewhere. When I do a perception check I see a crate just under the surface of the water that is high lighted which I assume where the loud beeping is coming from. How do you access this crate? I have tried everything I can think of to open it. Also there are some collectables I see displayed on the map not far from the crash site area that I can see with my perception in a hole underneath a bamboo like cover. I have spent waaaay to much time trying to get to these goods. How do I get down in that dang hole? LoL !! Sorry if these answers have been posted before.... I did do a search.... Honest I did do one..... I have the PC game version.