Frigates
WHITBY and
ROTHESAY class (Type 12)
BLACKWOOD
class (Type 14)
LEANDER
class (as built) (Improved Type 12)
AMAZON
class (Type 21)
BROADSWORD class (Type 22)
DUKE class (Type 23)
SALISBURY
class (Type 61)
TRIBAL
class (Type 81)
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British frigate designs of 1950
descended directly from the Loch-class frigates of World War 2.
Needing long-range convoy escorts but with naval shipyards already
saturated with war construction and repairs, during 1942–43 the Royal
Navy designed the Loch class for “American methods.” The design
parceled 80% of the ship into modules for prefabrication, largely by
British structural engineering factories that were underutilized
without their peacetime market for bridges and other exports. Since in
general such firms could cut but not bend steel, curved plating was
minimal. Small shipyards around the UK assembled the modules into
frigates. Drawings numbered four times those for standard methods and
construction costs were at least 25% higher but ship delivery was rapid
and if necessary could have been much more rapid. Although many
operational histories of the Atlantic campaign ignore frigates, David
K. Brown has noted that the Loch-class frigates, armed with precision
sonar to aim their new Squid mortars, were “the most deadly U-boat
killers of the war.” This design also proved flexible. As several
frigates
neared completion they were armed instead with anti-aircraft guns to
create
the Bay-class frigates.
Forecasting that the new, fast Type XXI U-boats would
flee underwater toward the waves to force a defending frigate to
abandon
pursuit lest slamming damage her hull, late in 1944 the RN began
studies
for a new escort with a thin, deep bow and 25-knot speed in high seas
for
a 10-knot advantage over a fast submarine. The studies considered a
ship
design to use the successful prefabrication method established for the
Loch
and Bay classes that could support either antiaircraft or antisubmarine
armament.
Strategic concern about possible Russian aggression
using captured German technology soon supplanted the conflict with the
defeated Axis powers. Designs for the postwar frigates were connected
with British strategic expectations of another long war similar to
World War 2. Provisions for prefabrication, dispersed
assembly under mobilization conditions, and alternative
packages or armament characterized
British frigate designs of the first postwar decade. Frigate
construction and crew training would need to be rapid during
mobilization. The Royal Navy designed two standard propulsion plants
for mobilization production: Y-100 high-pressure steam and Admiralty
standard range (ASR) diesels. The steam plant was matched to the
twin-screw ASW frigate.
In March 1947 the designs for anti-aircraft and
fighter-direction frigates were split from the original plan for a
common-hull frigate class. The anti-aircraft and
fighter-direction designs instead became a separate
common-hull frigate class with ASR diesel propulsion and with
alternative armament packages for the different missions. In 1950 these
alternatively-armed common-hull diesel frigates became Types 41 and 61.
The steam-powered twin-screw ASW frigate became Type 12.
© Mike Potter 2004.
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