To my mind, there should be two “must haves” to greatly increase both the usefulness and the survivability of the T31s.
1. A Sonar (whether this be a HMS or a TAS)
2. A Mk41 VLS Silo (I will not comment here on numbers, but obviously the more there are, without getting
ridiculous, then the greater the potential capability).
No objection. But please only AFTER the 5 remaining T26s order contract be signed ... As much as RN make T31 look like a full fat frigate, not only the review, but also just a new Prime Minister will be able to easily cut some T26 saying "I am reluctant to ...., but we now need a new way of blah-blah....".
In other words, only after 2024 or 2025 or so. Yes, this means most (or all) of the T31 hulls will be delivered without it.
So, seriously speaking, PERSONALLY, "up-arming" T31 issue shall be focussed on addition, not re-design.
- Sonar, both HMS and TAS, is good. We know there are spaces reserved for them. Of course, adding SeaSentor ship torpedo defense system (if not budgeted yet) will be of very high priority, anything before adding a sonar.
- VLS, I'm afraid there is not space left for Mk.41, without significantly cutting the hull. But, for "more missile", doubling CAMM (12 -->24) will be easy. Adding I-SSGW is also doable, even 16 of them.
- But, I'd rather improve the 57mm gun. Add radar FCS, add guided rounds. By 2025, at least anti-surface guided rounds will be there, I think. (On 40 mm, I can find no future improvement program on-going in the world. It's another concern on 40 mm).
- Also making it a USV-tactics lead-ship will be a good way to go. But, I have no good idea, what two (or three) "9.5m-class" USVs can do, other than surface patrolling (which is very important in gray-zone duty).
PS T31 has passed the "whole ship preliminary design review (WS PDR)" on August this year. Assuming the word definition is the same to that of my field, it means "all options fixed and now writing down the final design". Here design includes not only the blue print (actually 3D CAD), but also parts procurement timeline, assembly process, verification process (testing and qualifying) etc, virtually everything until the ship delivery. In general, it also includes staff/engineer/labour training timeline (seriously).
It is a huge amount of documentation (surely exceeding 100 kg or even reaching 1 tonne, if printed in paper). After the critical design review (CDR), which I think will come early next year, there is no chance to change the design. (No chance here means "without significant MORE MONEY to re-do many many details". If money is there, anything is possible!)