- Excerpt from Niku I
- On the lee side, the reef typically descends rather gently to a depth of about 12 meters, then becomes increasingly steep to about 40 meters, and then drops precipitously into the depths. Particularly off the northwest side of the island around Tatiman Passage there are arroyo-like features three or four meters deep and a meter or two wide, which the divers thought could easily catch and hold aircraft parts falling down from the reef flat, though none were noted. A shelf was noted at about 10-12 meters deep along the lee side, extending for some distance to the northwest from the vicinity of the Norwich City wreck. On the windward side the pitch of the reef is somewhat less precipitous and the reef is cut by "spur and groove" features--high energy channels radiating out from the island, generally quite straight, and one to two meters wide. The windward side also features a number of crater-like features that trap sand and could easily trap airplane wreckage were there any to be trapped. The reef on this side is also undercut at some points.