I was able to find this egg without coords. It can be found at the northeastern tip of the Riplash Ruins. Swim down a short distance just below the temple foundation where quest objective Raknar Drakkarlund is found. There is a pillar leaning against the crack's left side.The crack is large enough to swim into. The Terky egg lies in a pile of bones and rocks past the large egg on a pedestal. Happy hunting!