Their streamlined conning towers were designed to give them an underwater speed of 15 knots.
Imibhoshonqo yazo yokukopola ngaphezulu kwenkwili ngezipili nemibhobho zikwazi ukubona nantoni engaba isendleleni zazenzelwe ukunika zona isantya saphantsi kwamanzi seshumi elinesihlanu samaqhina.