GW58 June 1955
GW58 was an upgraded version of GW52A with the DNC's desired 4% growth margin and corrections to machinery weights (+200 tons). The result was effectively a repeat of the GW25C except for only two Bofors mounts. Armour was much reduced (1.5in Vs 4in) but stability was better 8.5ft GM Vs 6.75ft GM) and the missiles were stowed one deck lower. GW58 was considered the basis for a final design and for the first time reliable detailed calculations were made. The design was handed to the Controller on 15 June and sketch Staff Requirement TSD 2305/55 was written around it. Displacement was 15,400 tons (deep); dimensions 637 (oa) x 78 x 20ft 3in. Speed was 32kts deep and clean with four 30,000shp YEAD sets producing 120,000hp (32kts on 105,000shp), endurance 4,500nm at 20kts. Armament was two twin 6in, two twin 3in L/70, two twin 40mm L/70 and 48 Sea Slug missiles. The radar fit was one Type 901 director, six MRS-3, Type 984, Type 992 and Type 974. Self-defence Type 176 and Type 177 sonars were also fitted. Armour protection was 1.5in side and deck except for the machinery areas which had 1in deck armour. Complement was 80 officers and 970 ratings.
Drawing Note: This drawing based on official sketch drawings of GW58
GW60 August 1955
GW60 was the result of sketch Staff Requirement TSD 2305/55 was written around the GW58. The main differences were the provision for a VDS set instead of the usual Type 176/177 self-defence Asdics and space for the Y200 powerplant then under development.
Displacement was 15,800 tons (deep); dimensions 657 (oa) (645 wl) x 78 x 20ft 3in. Speed was 33kts deep and clean with four 30,000shp YEAD sets producing 120,000hp (32kts on 105,000shp), endurance 4,500nm at 20kts. Armament was two twin 6in, two twin 3in L/70, two twin 40mm L/70 and 48 Sea Slug missiles. The radar fit was one Type 901 director, six MRS-3, Type 984, Type 992 and Type 974. A self-defence Type 176 sonar was likely too. Armour protection was 1.5in side and deck except for the machinery areas which had 1in deck armour.
Further developments came at the request of the DNO who wanted either four twin 3in L/70 or two twins and two sextuple 40mm L/70 mounts. These became GW64 and GW69 respectively, while GW64A was DNC's design project with 6 extra Sea Slug missiles (54 total).
Drawing Note: This drawing based on official sketch drawings of GW60