[Schöneboom]

In daylight (submerged) attacks, I use only electrics, never steam torpedoes. Also, at 500 m & closing, there is the risk of the periscope being spotted if a) it's up for too long a time, &/or b) the U-boat is going over 2 kts, i.e., making a periscope wake. Taking many brief peeks with the periscope is better than one long view. Hope that helps!