Each year the Thunder Bay NMS staff deploy and retrieve all of the seasonal mooring buoys on sanctuary shipwrecks. The harsh winter conditions on Lake Huron make it impractical to leave the buoys out all year. The mooring buoys are re-deployed each spring at the beginning of May and retrieved each fall after October first. Also in the spring any newly permitted mooring systems are installed. Currently, 21 sanctuary shipwrecks have permanent moorings, which makes for safer diving and eliminates anchor damage at these often fragile sites. New moorings are installed as necessary permits are obtained. Check back often to find out which new sites have mooring buoys.