New tactics for U. S. Submarines in W. W. II
 

High periscope watch

A submarine on the surface with its periscope at full rise from about a 40 ft. height could view a great area. The submarine could study targets but also check the surface and sky all around. The only danger was if the sun glanced off the periscope lens. Otherwise how could anyone on the target spot a periscope tip two dozen miles away?

 

End run chase to attack

Submarines often used end runs to sneak well ahead of a target to work into the optimum position to attack. Using radar, they remaining unseen to overtake targets, because their surface speed was faster than "marus." Once ahead if a moonless night, they often remained on the surface with radar and lookouts guiding. They "ghosted in," presenting minimum silhouette. With moon light they sometimes submerging to radar depth so only radar antenna and periscope could be seen by the enemy, but speed was lower.