Talk:HMS Queen Mary

Main armament elevation
An editor has changed
 * The guns could be depressed to −3° and elevated to 20°, although the rangefinders controlling the turrets were limited to 15° 21' until prisms were installed before the Battle of Jutland in May 1916 to allow full elevation.

To
 * The guns could be depressed to −3° and elevated to 20°, although the director controlling the turrets was limited to 15° 21' until prisms were installed before the Battle of Jutland in May 1916 to allow full elevation.

The stated basis of this change was "elevating prisms were part of the director, not the rangefinder".

I have reverted this edit because the original information was backed up by a citation, and the change was not. I do not have a copy of NJM Campbell's Battle Cruisers, Warship Special 1 so I cannot check what it says.--Toddy1 (talk) 05:24, 28 July 2011 (UTC)

I'd need to see a copy of the cited work, but either the citation is wrong or the work itself in error. Coincidence rangefinders have prisms in them, but every such rangefinder is intrinsically capable of measuring ranges to infinity (albeit, with errors approaching infinity). The gun sights on a director (or the local ones on a gun), however, have a range of elevation that is finite and in some weapons, less than the elevation limits of the mounting. It is on these sighting telescopes to which super-elevating prisms are attached, and new cams on the sight's range dial expressed the relationship of range to these +6 degree elevations.

Page 4 of "The Sight Manual, 1916", ADM 186/216: The following methods of increasing the range to which guns can be laid are under consideration.

...

II. Telescope Sights, Director or otherwise. --Providing an optical attachment which can be clamped on the end of the telescope, and which deflects the line of sight 6 degrees downwards. These attachments have been supplied for Ottway 5-15 power telescopes to "Indomitable" and all later classes of battleships and battle cruisers in the proportion of one to each aloft director sight. No inaccuracy need be anticipated from constantly taking off and putting on the 6 degree attachment, whose accuracy is within one minute.

Whether these were provided to Queen Mary before her destruction I'd have to further research, but if prisms and cams were provided her to help her achieve greater elevation and hence range, there is no question that these were part of the pitch angle difference between her gun barrels and her sighting scopes, an optical/mechanical relationship entirely unrelated to rangefinder use. DulcetTone (talk) 17:31, 28 July 2011 (UTC)


 * thanks--Toddy1 (talk) 18:09, 28 July 2011 (UTC)
 * I'll second that. I'll have to check Campbell this weekend to see his exact wording, but I'm fairly certain that the manual trumps his book. Just be sure to cite it properly and we'll be OK.--Sturmvogel 66 (talk) 23:32, 28 July 2011 (UTC)

rangefinders in all four turrets
My comment wasn't as convincing as it could be... the photo on page 86 of Roberts's book augments the phrasing and the plan drawing he provides, clearly showing the ship had RFs in A and B in 1914. Apparently, QM was the first capital ship to enjoy this level of RF installation upon completion and it was to be retrofitted as possible in coming years in the earlier vessels. DulcetTone (talk) 19:09, 16 February 2012 (UTC)

There seems to be a common error in describing the function of the Director. According to J Brookes Dreadnought Fire control & Jutland, the Dreyer table provided elevation and deflection data for the gun turrets not the Director. The director provided another source of target bearing (the Rangefinder mounts being another), target range and range rate change. This data was fed to the Dreyer table and from it data was then transmitted to the turrets relating to elevation and bearing, including deflection. The Director did fire the guns. This information is not made clear in the written piece. Revisionist99 (talk) 13:25, 11 February 2013 (UTC)

salvage company looting the wreck
in 2016 reports of the wreck being looted by a Dutch salvage company http://thepipeline.info/blog/2016/05/22/exclusive-named-the-salvage-company-which-looted-jutland-war-graves-as-mod-fails-to-act/ — Preceding unsigned comment added by Man74 (talk • contribs) 14:48, 16 October 2016 (UTC)

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suggestion
change

HMS Queen Mary was the last battlecruiser >>> built <<< by the Royal Navy before the First World War.

to

HMS Queen Mary was the last battlecruiser >>> COMPLETED <<< by the Royal Navy before the First World War.

151.29.105.180 (talk) 10:30, 21 October 2021 (UTC)
 * Better, I think, to delete it entirely as a trivial point.--Sturmvogel 66 (talk) 00:17, 22 October 2021 (UTC)