Editing Turret ship (section)

===American developments===
[[File:USS Monitor plans.jpg|thumb|Inboard plans of {{USS|Monitor}}.]]
The gun turret was independently invented by the Swedish inventor [[John Ericsson]] in the United States.<ref name=Sandler>{{cite book|url=https://books.google.com/books?id=i9-0ZuKsMvIC|title=Battleships: An Illustrated History of Their Impact|author=Stanley Sandler|year=2004|publisher=ABC-CLIO|pages=27–33|isbn=9781851094103}}</ref> Ericsson designed USS ''Monitor'' in 1861. Erickson's most prominent design feature was a large cylindrical gun turret mounted [[amidships]] above the low-freeboard upper [[Hull (watercraft)|hull]], also called the "raft". The raft extended well past the sides of the lower, more traditionally shaped lower hull. A small armoured [[pilot house]] was fitted on the upper deck towards the bow, however, its position prevented ''Monitor'' from firing her guns straight forward.<ref>{{cite book |last=Tucker |first=Spencer |year=2006 |title=Blue & gray navies: the Civil War afloat |ref=Tucker06 |publisher=Naval Institute Press |location=Maryland |isbn=1-59114-882-0|page=171}}</ref> {{efn|Ericsson later admitted that this was a serious flaw in the ship's design and that the pilot house should have been placed atop the turret.}} One of Ericsson's prime goals in designing the ship was to present the smallest possible target to enemy gunfire.<ref name="Thompson">{{cite journal|last=Thompson|first=Stephen C.|year=1990|title=The Design and Construction of the USS Monitor|ref=Thompson90|journal=Warship International |publisher=International Naval Research Organization |location=Toledo, Ohio| volume=XXVII|issue=3 |issn=0043-0374}}</ref>

The turret's rounded shape helped to deflect cannon shot.<ref>{{cite book |last=Mindell |first=David A. |year=2000 |ref=Mindell |title=War, Technology, and Experience Aboard the USS Monitor |publisher=Johns Hopkins University Press |isbn=978-0-8018-6250-2|page=41}}</ref><ref>{{cite book |last=McCordock |first=Robert Stanley |title=The Yankee Cheese Box |ref=McCordock |publisher=Dorrance |year=1938 |page=31}}</ref> A pair of [[donkey engine]]s rotated the turret through a set of gears; a full rotation was made in 22.5 seconds during testing on 9 February 1862.<ref name="Thompson"/> This design was technologically inferior to Coles', and made fine control of the turret difficult.<ref name=Sandler/>  If turret rotation overshot its mark it was difficult to make a correction. Either the engine would have to be placed in reverse or another full rotation was necessary.

Including the guns, the turret weighed approximately {{convert|160|LT|t|0}}; the entire weight rested on an iron spindle that had to be jacked up using a wedge before the turret could rotate.<ref name="Thompson"/>  The spindle was {{convert|9|in|cm|0}} in diameter, which gave it ten times the strength needed in preventing the turret from sliding sideways.<ref>{{cite book |last=Baxter |first=James Phinney, 3rd |author-link=James Phinney Baxter III |title=The Introduction of the Ironclad Warship  |url=https://archive.org/details/introductionofi00baxt |url-access=registration |edition=reprint of the 1933 publication |year=1968 |publisher=Archon Books |location=Hamden, Connecticut  |oclc=695838727 <!-- |url=https://books.google.com/books?id=4CQzAAAAMAAJ no preview--> |ref=Baxter|page=[https://archive.org/details/introductionofi00baxt/page/256 256]}}</ref> When not in use, the turret rested on a brass ring on the deck that was intended to form a watertight seal. In service, however, this proved to leak heavily, despite [[caulking]] by the crew.<ref name="Thompson"/>  The gap between the turret and the deck proved to be a problem as debris and shell fragments entered the gap and jammed the turrets of several {{Sclass|Passaic|monitor|3|warship}}s, which used the same turret design, during the [[First Battle of Charleston Harbor]] in April 1863.<ref>{{cite book |last=Canney| first=Donald L. |title=The Old Steam Navy |ref=Canney |publisher=Naval Institute Press|location=Annapolis, Maryland <!-- |url=https://books.google.com/books?id=GzAhAQAAIAAJ no preview--> |year=1993 |volume=2: The Ironclads, 1842–1885 |isbn=0-87021-586-8|pages=79–80}}</ref> Direct hits at the turret with heavy shot also had the potential to bend the spindle, which could also jam the turret.<ref>{{cite book |title=Our Iron-clad Ships: Their Qualities, Performances, and Cost. With Chapters on Turret Ships, Iron-clad Rams |last=Reed |first=Sir Edward James |ref=Reed |location=London |publisher=J. Murray |year=1869 |url=https://archive.org/details/ourironcladship01reedgoog|pages=[https://archive.org/details/ourironcladship01reedgoog/page/n295 253]–54}}</ref><ref>{{cite book |last=Broadwater |first=John D. |title=USS Monitor: A Historic Ship Completes Its Final Voyage  |publisher=Texas A&M University Press |year=2012 |isbn=978-1-60344-473-6 |url=https://books.google.com/books?id=ht7Im50Mec8C |ref=Broadwater|page=8}}</ref><ref>{{cite book |last=Wilson |first=H. W. |title=Ironclads in Action: A Sketch of Naval Warfare From 1855 to 1895 |volume=1 |ref=Wilson |year=1896 |publisher=Little, Brown |location=Boston |url=https://books.google.com/books?id=M3DgGKmaHDEC|page=30}}</ref>

The turret was intended to mount a pair of {{convert|15|in|mm|adj=on|0}} [[smoothbore]] [[Dahlgren gun]]s, but they were not ready in time and {{convert|11|in|mm|adj=on|0}} guns were substituted.<ref name="Thompson"/> Each gun weighed approximately {{convert|16000|lb}}. ''Monitor''{{'}}s guns used the standard propellant charge of {{convert|15|lb|kg}} specified by the 1860 ordnance for targets "distant", "near", and "ordinary", established by the gun's designer Dahlgren himself.<ref>{{cite book |last=Field |first=Ron |year=2011 |title=Confederate Ironclad vs Union Ironclad: Hampton Roads |ref=Field |publisher=Osprey Publishing |isbn=978-1-78096-141-5|page=33}}</ref> They could fire a {{convert|136|lb|1|adj=on}} round shot or shell up to a range of {{convert|3650|yd}} at an elevation of +15°.<ref>{{cite book |last1=Olmstead |first1=Edwin|last2=Stark|first2=Wayne E. |last3=Tucker |first3=Spencer C. |year=1997 |title=The Big Guns: Civil War Siege, Seacoast, and Naval Cannon |ref=Olmstead |publisher=Museum Restoration Service |location=Alexandria Bay, New York |isbn=0-88855-012-X|page=90}}</ref><ref>Lyon, David & Winfield, Rif ''The Sail and Steam Navy List, all the ships of the Royal Navy 1815-1889'', pub Chatham, 2004, {{ISBN|1-86176-032-9}} pages 240-2</ref>