Tribal class frigate

The Type 81, or Tribal class, was a class of seven general-purpose frigates for the Royal Navy designed during the 1950s that served throughout the 1960s and 1970s with limited service during the 1980s.

History

The Tribals were designed during the 1950s as a response to the increasing cost of single-role vessels such as the Type 14s. They were first such 'multi role' vessels for the Royal Navy. They were designed specifically with colonial 'gunboat' duties in mind, particularly in the Middle East. They were therefore designed to be self-contained warships with weapon and sensor systems to cover many possible engagements, air conditioning to allow extended tropical deployment and such 'modern' habitability features as all bunk accommodation (as opposed to hammocks).

Design

They were the first class of the Royal Navy to be designed from the start to operate a helicopter and the first small escorts to carry a long-range air search radar, the Type 965 with a single 'rake' AKE-1 antenna. They were armed with two 4.5 inch Mark 5 main guns salvaged from scrapped Second World War destroyers. Although these mountings were refurbished with Remote Power Control (RPC) operation, they still required manual loading on an exposed mounting. From the outset they were designed to carry the new GWS-20 Sea Cat anti-aircraft missile system but all except "Zulu" initially shipped single Mark 7 Bofors guns in lieu. In the event, budget restraints led to only "Ashanti", "Gurkha" and "Zulu" being so fitted.

The Tribals were the first modern RN ships designed to use a combination of power sources, a feature which had been trialled with limited success in the 1930s in the minelayer HMS "Adventure". An additive mix of steam and gas turbine called "COmbined Steam and Gas" COSAG was used. This gave the rapid start-up and acceleration of a gas turbine engine coupled with the cruising efficiency and reliability of the steam turbine. They would cruise on the steam plant and use both systems driving the same shaft for a high-speed "boost". They suffered however from being single-shaft vessels which severely limited manoeuvrability, acceleration and deceleration.

hortcomings

The costs for the Tribals escalated above the costs first envisaged, and the original order of ships, over twenty, was cancelled after the first seven ships had been completed. The ships were rather small, at 360 ft (110 m), which prevented much modernisation and were always going to be limited by the single-shaft propulsion. The class were still good warships despite their cost, proving the usefulness of the general purpose frigate concept, as perfected in the excellent Type 12M "Leander" class and modern Type 23 class.

ervice

The class served throughout the 1960s and into the 1970s fulfilling their designed general purpose "colonial gunboat" role. When change in British foreign policy made this role redundant they found themselves being pressed into service in home waters in the "Cod Wars" of the 1970s. They were not particularly suited to these duties however, as they had a hull form optimised for the calm, shallow water of the Persian Gulf and with only a single shaft were unable to manoeuvre with the Icelandic gunboats at close quarters.

All were decommissioned from the Royal Navy during the mid-to-late 1970s with the manpower crisis also attributing to the rapid removal of the class from service. They were however given a brief reprieve by the Falklands war, with 3 mothballed Tribals,HMS Gurkha,HMS Tartar and HMS Zulu being reactivated to cover ships deployed to the South Atlantic or undergoing long-term repairs after the conflict. These ships were sold in 1984 to Indonesia.

hips

References

* "Jane's Fighting Ships 1977-78", Jane's Yearbooks, ISBN 0-5310-3277-9

ee also

*Tribal class destroyer (1905)
*Tribal class destroyer (1936)