The problem is that the values vary depending upon what you want to do. However, in the spirit of the thread:

Two parameters: Ship type and Technology level, both subjective to some extent, but that’s life. This will give something that everyone can critcise anyway 😎 🙂

I am ignoring SSBNs, because they are used then everyone loses

Type/Size
Supercarrier: 10
Medium Carrier: 8
Small carrier: 5
SSN: 6
SSK: 2
Guided missile ship >6000 tonnes: 4
Guided missile ship 3000 to 6000 tonnes: 3
Corvette/OPV/other ship incl auxiliary supply vessel: 2
Small craft : 1

Technology levels:
Class Design post 2000: 6
Class design post 1980: 3
Prior to that: 0
Add one if it has had a major refit in a later period than its design