Editing O'Brien-class destroyer (section)

=== Comparisons with other "thousand tonners" ===
The "thousand tonners" were the 26 United States Navy destroyers of five classes—''Cassin'', ''Aylwin'', ''O'Brien'', {{sclass|Tucker|destroyer|5}}, and ''Sampson''—so named because they were the first U.S. Navy destroyers to have displacements greater than 1,000 long tons<!-- not converted since it's converted in previous paragraph -->.<ref name="Con-122-123" /><ref group=Note>The {{sclass|Aylwin|destroyer|4}} is considered a part of the {{sclass|Cassin|destroyer|4}} by ''Conway's All the World's Fighting Ships 1906–1921'' (p. 122), but is classed separately by the United States Navy. See, for example, {{cite DANFS | author = Naval History & Heritage Command | author-link = Naval History & Heritage Command | url = http://www.history.navy.mil/research/histories/ship-histories/danfs/a/aylwin-ii.html | title = Aylwin (Destroyer No. 47) ii }}</ref> The ''Cassin'' class, the first of the thousand tonners, displaced about a third more than the preceding {{sclass|Paulding|destroyer|4}}.<ref name=Con-122-123 /> The introduction of the thousand tonners led to the ''Paulding''s and other older, smaller displacement destroyers of previous classes to be dismissively called "flivvers",<ref name=Con-121 /> a nickname also commonly applied to the [[Ford Model T]].<ref>Cashman, p. 278.</ref><ref group=Note>According to Cashman (p. 278), a flivver—a [[portmanteau]] of "for the liver"—was any small, inexpensive automobile that shook the liver while in motion.</ref>

[[File:USS Melville (AD-2) and destroyers in World War I.jpg|thumb|left|''O'Brien'' class member {{USS|Ericsson|DD-56|2}}, between the closely related {{sclass|Tucker|destroyer|0}} ships {{USS|Jacob Jones|DD-61|2}} ''(left)'' and {{USS|Wadsworth|DD-60|2}}, is moored by destroyer tender {{USS|Melville|AD-2|2}} at [[Queenstown, Ireland]], in 1917.]]
The ''O'Brien'' class was the third of the five classes of "thousand tonners". The earlier ''Cassin''- (DD-43 to DD-46) and ''Aylwin''-class (DD-47 to DD-50) ships were about the same length as the ''O'Brien'' ships and all had median displacements in the range of {{convert|1020|-|1050|LT|MT}}; the later ''Tucker''- (DD-57 to DD-62) and ''Sampson''-class (DD-63 to DD-68) ships were about {{convert|10|ft|m}} longer and had median displacements of {{convert|1090|-|1100|LT|MT}}. All five classes were armed with four 4-inch guns, but the torpedo size and complement varied. All were equipped with four twin torpedo tubes loaded with eight torpedoes except for the ''Sampson''s (which had four triple tubes carrying twelve torpedoes), but the ''Cassin''  and ''Aylwin'' classes were armed with {{convert|18|in|mm|0|adj=on}} torpedoes. The ''O'Brien'' ships were the first armed with the new 21-inch Mark 8 torpedoes; the ''Tucker'' and ''Sampson'' ships also used the 21-inch torpedoes. The ''Sampson''s were the only group originally equipped with anti-aircraft guns, a pair of [[QF 1 pounder pom-pom|{{convert|1|pdr|adj=on}} guns]] with a [[caliber]] of {{convert|37|mm|in|2|abbr=on}}.<ref name=Con-122-123 />