Notice to Mariners – North Coast Cornwall – Wave Hub Buoy Posted on September 23, 2013 at 12:00 am. Please be advised that the Wave Hub SW special mark (charted position 50 deg 20.70’N 05 deg 37.24’W) is reported missing. The buoy is a 3 metre diameter yellow steel structure approximately 4 metres high with a cross top mark. Mariners are advised to navigate in the area with caution.