Commercial off the shelf

The Flower class corvette HMS Alisma was built using COTS components.

The Guardian class FSS David W. Panuelo was built using COTS components.

The term commercial off the shelf (COTS) technology is used when referring to military vehicles, military vessels, military aircraft, that are not built with military grade components, unlike vehicles, vessels, and aircraft built to the highest possible standard, because fighter's lives might depend on using the highest possible quality.

The choice to use commercial off the shelf components makes the initial construction faster, easier and cheaper.

During World War 2's Battle of the Atlantic the allies needed large number of convoy escort vessels. While destroyers would have been the ideal escorts, with high-speed steam turbine engines, and mounting the latest weapons suites, there were a limited number of shipyards capable of constructing destroyers. Moreover, the Royal Navy also wanted those shipyards to build and maintain larger warships.

The Flower class corvettes relied on triple expansion steam engines, an old technology, and could be built in older smaller shipyards. New Corvette hulls were much cheaper than destroyers, and could be built in a fraction of the time it took to build a destroyer.

In the late 20th century, and early 21st century, Australia chose to use COTS components to build almost four dozen small patrol vessels for its small neighours in the Pacific Island Forum. During the thirty year lifetime of these vessels they would rely on less experienced technicians for maintainence, and it would be best if the parts they used were widely available.