In the Northern Atlantic visibility is normally very poor, this is further compounded by the fact that not a lot of light penetrates to the extreme depth that the U-Who lies in. Visibility within shipwrecks is further reduced due to the silt and fine particles which normally reduce the visibility to zero. This lack of vis cause Chris and Chrissy Rouse to lose their way inside the wreck which wasted precious minutes as they looked for an escape. Furthermore, the low vis outside of the shipwreck caused them to not find their decompression tanks or the anchor line forcing them to do a free accent straight to the surface.