TR1 wrote:I would be very hesitant to use that chart for anything, even relative comparison.
Dont use those chart numbers as Gospel Truth but more like trend and then try to co-relate it to USN ONI release showing trends in quitening.
Even Russian sources dont differ much on that front.
You would get a good idea on where Borei would stand without depending on the numbers of the chart or other sources.
The problem is there is no fixed number to pin when it comes to acoustic quitening , there are other factors that would infulence subs quitening in a specific environment like temperature , salinity of sea , wind condition , depth , surface layers etc these are very dynamic depending on the month of the year and could change drastically in few km distance add to that complexity these condition also varies on the ocean like barrent sea , Artic ,Atlantic , Indian ocean these condition would vary on month and time of day.
Hence you need huge amount of ocean data spread over many months and years to get a good picture of your surrounding to aid your sensors and that itself needs to be periodically updated.
Submarine is a very complex subject unlike aircraft where your RCS values wont vary much if you fly over american airspace or russian airpspace.
I would honestly be surprised if the smaller Astute can match the sound dampening the Virginia and Severodvinsk achieve.
Astute were designed to hunt the Akula/Shuka-B , so expect it to be as quiter as virgnia , infact in a latest exercise between USN Virginia and RN Astute some where in US water the Astute did well and came out top.
Smallness does not affect the acoustic condition as much they affect the ability to carry more weapons and consequently more people to man them , a small submarine can have same or better acoustic quality as big subs , where they would get hurt is the ability to carry large and different sensor array for eg their nose will be smaller and consequently the sonar array impacting detecting range , and their ability to carry less amount of weapons affects persistance in enemy territory in actual war.
Yasen is actually double hull sub so it appears to be always bigger than single hull US,UK sub but yasen carry more amount of weapons and can fit bigger and more varied sensor array , ofcourse they would cost more as big ness also impacts other areas like manning , power needs , food storage etc