by Rick E Davis » Sat Jan 31, 2026 9:25 pm
On all destroyers with the newer "Square-Back" Mk 37 director, FLETCHER's and newer, initially had the Mk 12 radar replacing the Mk 4 radar and the Mk 22 when available. (production of the Mk 22 lagged the Mk 12 by about six months).
On the older destroyers with the "Angle-Back" Mk 37 director, SIMS, BENSON, and GLEAVES classes (the earlier Mk 37 directors didn't have room inside for Mk 12 radar equipment) couldn't have the Mk 12 radar. The USN tried installing Mk 22 radars on many of the units with the earlier Mk 37 Angle-back directors in combination with the Mk 4 radar directors, but the results weren't satisfactory. Eventually the newer Mk 28 radar (circular antenna), which had a smaller antenna and was less capable compared to the Mk 25 radar installed post-war on FLETCHER, SUMNER, and GEARING classes, but was better than the earlier Mk 4 radar.
Yes the added boxes on the back of the Mk 37 director were for the newer radar equipment.
For the larger units (battleships, cruisers, and carriers) which had the "angle-back" or "square-back" Mk 37 directors is a lot more complicated. Which units got which was depended on when they were built in the production line. For units initially equipped with angle-back Mk 37 directors, in some cases the original director was modified for newer radars. Basically, the shell needed to be modified.
On all destroyers with the newer "Square-Back" Mk 37 director, FLETCHER's and newer, initially had the Mk 12 radar replacing the Mk 4 radar and the Mk 22 when available. (production of the Mk 22 lagged the Mk 12 by about six months).
On the older destroyers with the "Angle-Back" Mk 37 director, SIMS, BENSON, and GLEAVES classes (the earlier Mk 37 directors didn't have room inside for Mk 12 radar equipment) couldn't have the Mk 12 radar. The USN tried installing Mk 22 radars on many of the units with the earlier Mk 37 Angle-back directors in combination with the Mk 4 radar directors, but the results weren't satisfactory. Eventually the newer Mk 28 radar (circular antenna), which had a smaller antenna and was less capable compared to the Mk 25 radar installed post-war on FLETCHER, SUMNER, and GEARING classes, but was better than the earlier Mk 4 radar.
Yes the added boxes on the back of the Mk 37 director were for the newer radar equipment.
For the larger units (battleships, cruisers, and carriers) which had the "angle-back" or "square-back" Mk 37 directors is a lot more complicated. Which units got which was depended on when they were built in the production line. For units initially equipped with angle-back Mk 37 directors, in some cases the original director was modified for newer radars. Basically, the shell needed to be modified.