first of all, dew is meant to replace ciws and its under testing for a long time. considering high speed and low flying ashm, both usn and israel navy replace gun ciws with missiles- ram,sea drome. both are ciws. essm is medium range, camm-er medium range. aster 15 srsam. camm - qrsrsam like barak1 replacement. sm2 series from long to exo with near hypersonic.each sam have its own advantage and disadvantages. quad packing. packing depend on vls, not missile. if a missile designed upon a common vls, then packing is good and right now, only usa, eu, china having such one, india dont. brahmos use its own vls. barak1 its own. baral8/er its own etc, so no quad packing for now. issue is with brahmos, huge and 3ton. and smart. just image 128 uvlas, a boat of 150000t plus. and not going to work because torpedo decoy, depth charge etc cant fit. also drdo having zero plan for such. back to sam. barak8 vs er. barak8 - qr/sr/mr sam[unique] and barak8er lr sam, means if p18 choose barak8, then it need qrsrsam like camm, or like you said, high speed AShM's and other low flying high speed plus low speed/high speed thermal low flying sea skimming stealth missile can easily target p18. quad packing means. putting four missile in one cell and navy dont need such capability right now and until drdo develop and certify 1500km hypersonic anti air/space missile, 1500km naval ssm both cruise and non, or replacing brahmos with 1t/1.5tkg missile and no to ship based smart. or keeping common vls for air defence missile and another for surface/sea attack missile, and you see drdo dont have any such plans. drdo also dont have plans for barak8/er replacement. quad packed missiles- essm medium sam similar to barak8, sea captor qrsrsam, cammer er mrsam, except medium range sam, srsam having single packed vls. your theory is not correct for p18, becz why quad pack. usn vls too big and carry four folding wing sea sparrow[essm], and sylver big enough for 4 camm and sylver having different versions, none of them applicable to IN and DRDO. I still need suggestions on iep of p18 and rf sensor, plus eots. quad pack only possible if barak8er vls capable of carrying 4 qr/sr sam. and building a suitable canisters