Unless I am being completely thick (always possible), they seem to be looking for something capable of hitting a submerged target beyond the range of its current or future heavyweight torpedoes. Assuming an entry point fairly close to the target, they are therefore looking at a c.35Nmi + range, so something exceeding three times the range of the Mk41 VLS launched RUM-139 VL-ASROC (or for those of us of a certain age, that of Ikara) or more than one and a half times that of the Japanese Type 07 Vertical Launch Anti-Submarine Rocket (also Mk41 VLS launchable).
The LRAW concept provides an extended range delivery means for a Lightweight Torpedo (LWT) or Very Light Weight (VLWT) Torpedo effector against submarine contacts, cued by organic or third-party sensor detection. Engagement ranges are to comfortably overmatch those of current and forecast threat Heavy Weight Torpedoes.
The solution requires an interchangeable, stand-off, quick-reaction, all-weather ASW weapon delivery capability that enables a UK LWT to reach a water-entry point for a targeted submarine from any Mk41 VLS-fitted platform. LRAW will need to integrate with RN Combat or Sonar Systems and must be ‘Secure by Design’.
(My emphasis)