Tides:
A correct and extensive knowledge of the tide is essential to good work, if navigating salt water. A constant study should be made of the tides, learn their strength, direction and height. Always carry a tide book, and make a habit of consulting the tables. By knowing the exact time of the current changes and the locations where they change earliest you will save hours of time in getting from port to port. In estuaries and sounds the current generally runs longest in mid-channel and changes on the inshore first. So if carrying the last of a tide keep in midstream; if using the first of it keep inshore. Eddies can be found by examining the shore line, and drawing conclusions from the trend of the coast. Much distance can sometimes be gained by working eddies if sailing against an adverse current.