In one of the many pictures I've seen there was a good one of the port side in which this "turret" looked more like a windlass of sorts. So that may very well play to the docking tether idea. Regardless, take a look at the camera in each of these two shots. Looks as though someone might be keeping an eye on the photographer. http://www.flickr.com/photo_zoom.gne?id=102997978&size=o http://www.flickr.com/photo_zoom.gne?id=102997982&size=o In case you don't see them, look on the underneath side of the sponsons.