To get your gear back in rough landing in the peruvian jungle in Shadow of the Tomb Raider go up to the plane. Go down into the pond and swim down to the plane and grab a sharpened object. To collect salvage to sharpen the knife walk around the area and find salvage boxes.
Once you have found 3 return to your camp and craft a knife. Go back to the pond area and cut both ropes holding up your gear.