No one remembers why the Gryph-hound went down but she was lost with all hands in the malignant forest many years ago and it was months before a passing sky-ship found the wreck. It was already overgrown and rotting on the forest floor. The forests of the Harrowmark are a dangerous place for a sky-ship captain who does not know his trade!
Edit: I've been asked a few times for paint recipes for the wreck and the anchor:
It's a Playmobil anchor, with the hollow middle filled with greenstuff that I "dimple" textured. I painted it with Typhus Corrosion (over a dark grey base) then washed it with 10-1 Lahmian Medium / Ryza Rust, then a wash of Agrax Earthshade.
The timbers of the wreck are just sprayed black undercoat, zenithal spray Mechanicus Standard Grey, drybrushed Ushabti Bone, washed with Nuln Oil. The green mossy stuff is Plaguebearer Contrast paint. The barnacles are painted Wraithbone then Skeleton Horde Contrast.