plawolf
Lieutenant General
The circular inner tube is needed for cold launch SAMs to create a tight seal around the missile to maximise lift from the gas charge and minimise the size of charge needed. It also doubles up as a guide tube to ensure the missile stays properly aligned when launched so suddenly. Without that inner tube, there is every chance the missile would tumble even before it fully exists the VLS.It would make sense if you wish to retain the older VLS and simply use the canisters from the land based missile. But I don't see the sense and effort of putting tube canisters into the square canisters as that lengthens the process, and this is likely done at the factory. Which means you still have two separate stock keeping units instead of one.
Even if a round based inner canister is used inside the square canister, it does not assure that this inner tube canister is the same as that used for the land based missile.
The reason why I like to get rid of the circular VLS is that its mechanically complicated, with each VLS requiring its own mini crane to help load the missile. But this disadvantage might still be livable.
An update to the main radars is necessary. Its not an issue of technological obsolescence, even if an AESA design of 20 years old like needs to have some update, but its necessary for parts attrition and wear. In an MLU a lot of things are replaced for new, even if they are identical parts. The older parts are due to expire, simply because wear and tear and electronics do have an expiration.
For an older radar you would have to stockpile all the T/R modules originally used with the radar at the time of its launching. Or you can do is replace the old T/R modules with that of a much more recent radar that's currently in production, as each of the older modules burn out and ran out of supply. So a radar refresh is absolutely necessary from a logistical viewpoint and with the collateral benefit of a big boost from the tactical standpoint, making the refreshed radars much more closer to the performance of the radars used in the latest Type 052D iteration.
So logistically and from a servicing standpoint, it would make sense replacing the modules used on the Type 346 to the modules used in the latest Type 346A subvariant. The replacement operation would take place within the ship itself and no need for dry docking. You can also update the back end electronics. If the newer generation modules perform better than the old one, you have the bonus of the refitted radar to perform superior to the original. Part of an MLU is to bring the ship as close as possible to the same maintenance standard as the other ships (hence why I still think the VLS change needs to happen). This isn't being done for the cost or the tactical viewpoint but from a logistical standpoint. This is why the Project 956E refit is mostly a sidegrade rather than an upgrade and the same goes to the 052B refit.
All cold launch VLS uses the circular inner tubes. The UVLS gives the PLAN the added option to use hot launched missiles as well, which don’t need the inner tube.