[Bob Ireland]

***Three!***

The problem, I surmise, is proximity. #2 I presume you mean left center about same level as #1, but it seems perilously close, given lack of depth of field - and me being a land lubber! #3 - a long shot - somewhat below #1 ... still seems awful close, however. Of course they might not be Los Angeles class subs, just diesel putt putts.

[STARLIT]

Reading

Periscopes on submarines may be as long as 60 feet (18 m). When a submarine is submerged to a depth that is equal to the length of the periscope tube, it is considered to be at periscope depth.