More info on the history of the Drews, the Drew Lumber Co., and the Florida railway can be found at www.taplines.net.
Most likely because, at that point in time, most sailing ships either used sails of were powered by a motor and had large smokestacks that would have likey hit and damaged the bridge. That's just a theory though.
Does anyone know why it was used as a rotating bridge? Why not just have a solid bridge installed?
Unfortunately no preservation efforts have been made. It has been sitting in this position, untouched since the 1920's. At one point there was the idea to use it as a normal traffic bridge, but no efforts towards that have been made either.
Have any preservation efforts been initiated?
All I can say is wow! This may be one of the oldest and most important historic bridges in Florida. If it was moved in 1899, think how old it may be in reality.