Those numbers, 37/33 represent the middle numbers for a position based on latitude and longitude.For example,the weather bouy 45005 location is
41' 40' 36' N
82' 23' 54' W
For quick reference to that location we would say the bouy is located at 40/23.That will put you within a mile if that precise location.Each middle number of latitude is close to one mile in distance and each middle number of longitude is roughly .85 miles.Charters and fishermen use and share these numbers to let others know where their location is on the lake.