model royal navy vessel type designation

[chuck]

since the 1950s the Royal navy has designated its warship designs with a type number, so type 42 is the sheffield class destroyer, type 82 is bristol class destroyer, type 22 is broadsword class frigate, etc

How are these type numbers assigned? is there a range of numbers reserved for a particular type of ship or class of intended missions?

[chuck]

but how are these numbers assigned? they do not appear to be sequential. for example the soviet/russian project number scheme appears to be roughly sequential in the order with which the design requirements were issued.

[maxim]

The numbers are sequential, but there are different series of Types and for me it does not appear to be logical in all cases.

ASW/GP Frigates: Type 12 - 32

Anti-aircraft ships: Type 41 - 45

Aircraft direction frigate (?): Type 61

???: Type 81 - 83 (81: sloops of the Tribal class, 82: large guided missile of the Bristol class, 83: large guided missile destroyers replacing the Type 45)


I do not understand the 80s series and I also do not understand, why the Bristol class is Type 82, the Daring class Type 45 and the replacement for the Type 45 is the Type 83...

[Admhawk]

This mostly sums it up,

https://en.wikipedia.org/wiki/Type_syst ... Royal_Navy

There were also many design studies and proposals that didn't get a type number and changing design criteria, weapon and sensor system development, and budget constraints and political whims meant definitions were flexible.

After WWII Frigate designs kept growing and Destroyer designs started to look like cruisers then shrank again, so there was an overlap between them which is why you see mixing of the numbers.

The book British Destroyers and Frigates by Norman Friedman goes into the history of the designs in detail if you want to understand the intricacies of each design.

[maxim]

The Wikipedia explains it also only partially.

Why there is a 30s series of "general purpose frigates" and a 80s series of "general purpose frigates/destroyers/sloops"? And why there there are general purpose frigates between the anti-submarine frigates, e.g. the Type 12I and the Type 21?