OK, while all of their properties are still being tweaked, here is the list of buyables as it stands at the start of the game (before the US or Japan might add to the list),
ITEM ----------------------------- Example of ships outfitted with item,
AXIS
15in double turret --------------- Bismarck, Tirpitz (main guns)
11in triple turret --------------- Scharnhorst (main guns)
11in double turret --------------- Schleswig-Holstein (main guns)
8in double turret ---------------- Prinz Eugen (main guns)
6.7in antiship guns -------------- Schleswig-Holstein (2nd biggest caliber)
5.9in antiship guns -------------- Bismarck, Tirpitz (2nd biggest caliber)
4.1in antiship guns -------------- Prinz Eugen (2nd biggest caliber)
4.1in multirole guns ------------- (hard to discern, depends on turret structure)
4in antiship guns ---------------- Scharnhorst (3rd biggest caliber)
4in multirole guns --------------- (hard to discern, depends on turret structure)
3.5in antiship guns -------------- Graf Spee (3rd biggest caliber)
3.5in multirole guns ------------- (hard to discern, depends on turret structure)
40mm AA cluster ------------------ MANY
37mm AA cluster ------------------ MANY
20mm AA cluster ------------------ MANY
quad torpedo launcher ------------ Cruisers & Destroyers (usually on deck), Subs
double torpedo launcher ---------- Cruisers & Destroyers (usually on deck), Subs
single torpedo launcher ---------- Cruisers & Destroyers (usually on deck), Subs
hedgehog cluster ----------------- primarily Destroyers, not many AXIS examples
depthcharge cluster -------------- primarily Destroyers
antisubmarine 'hooks' ------------ JAPANESE Destroyers, available nonetheless
hanging plate armor -------------- seen primarily in tanks, but plausible
welded plate armor --------------- refits
torpedo bulge ------------------- no prominent AXIS example
improved antiship radar ---------- refits
improved antiair radar ----------- refits
advanced antiship radar ---------- refits
advanced antiair radar ----------- refits
sonar ---------------------------- refits
improved sonar ------------------- refits
ALLIED
16in triple turret --------------- Nelson, Rodney (main guns)
15in double turret --------------- Hood (main guns)
14in quad turret ----------------- King George V (main guns)
14in double turret --------------- King George V (main guns)
13.5in quad turret --------------- Centurion (main guns)
13.5in double turret ------------- Centurion (main guns)
6in antiship guns ---------------- Nelson (2nd biggest caliber) ,Newcastle (main guns)
5.5in antiship guns -------------- Furious, Hermes (main guns)
5.25in antiship guns ------------- King George V (2nd biggest caliber)
4.7in antiship guns -------------- Nelson, Rodney (3rd biggest caliber)
4.7in multirole guns ------------- (hard to discern, depends on turret structure)
4.5in antiship guns -------------- Formidable, Ark Royal (main guns)
4.5in multirole guns ------------- (hard to discern, depends on turret structure)
4in antiship guns ---------------- Hood (3rd biggest caliber)
4in multirole guns --------------- (hard to discern, depends on turret structure)
3in antiship guns ---------------- Dunedin (2nd biggest caliber)
3in multirole guns --------------- (hard to discern, depends on turret structure)
40mm AA -------------------------- MANY
20mm AA -------------------------- MANY
0.5in (13mm) AA ------------------ MANY
quad torpedo launcher ------------ Cruisers & Destroyers (usually on deck), Subs
double torpedo launcher ---------- Cruisers & Destroyers (usually on deck), Subs
single torpedo launcher ---------- Cruisers & Destroyers (usually on deck), Subs
hedgehog cluster ----------------- primarily Destroyers
depthcharge cluster -------------- primarily Destroyers
antisubmarine 'hooks' ------------ limited examples, a rareity
hanging plate armor -------------- seen primarily in AXIS tanks, but plausible
welded plate armor --------------- refits
torpedo bulge ------------------- Vanguard (ship was completed late)
improved antiship radar ---------- refits
improved antiair radar ----------- refits
advanced antiship radar ---------- refits
advanced antiair radar ----------- refits
sonar ---------------------------- refits
improved sonar ------------------- refits
The values, or more succinctly, what all these lovely things do will be posted later (soon I hope)!