Went off Swanage Pier again this time with Mike Westbrook. Visibility was better than previous dive and got down to a better depth. This time we tried to swim along under the old pier, but found it very difficult to stay under it. We found ourselves coming up some way from the old pier in danger of being run down by boats. Saw a bigger crab and found a fold-up beach chair which I erected and tried to sit on...very difficult underwater! We got separated many times and at one point waited a few minutes at the surface for Mike only to find he was behind me all along. Lesson learned: on being separated from buddy rotate continuously on the surface.