View source for Indefatigable Class Battlecruiser (1909)

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|-
! colspan=6 align=left|Overview of 3 vessels
|-
| colspan=6 align=left|<small>Citations for this data available on individual ship pages</small>
|-
! align=center | Name 
! align=center | Builder 
! align=center | Laid Down 
! align=center | Launched 
! align=center | Completed 
! align=center | Fate
|- align=left
| {{Template:UK-Indefatigable}}
|[[Devonport Royal Dockyard]]
|23 Feb, 1909
|28 Oct, 1909
|1911
|Sunk 31 May, 1916
|- align=left
| {{Template:UK-NewZealand}}
|[[Fairfield Shipbuilding and Engineering Company]], Govan
|20 Jun, 1910
|1 Jul, 1911
|1912
|Sold 19 Dec, 1922
|- align=left
| {{Template:AU-1Australia}}
|[[John Brown & Company]], Clydebank<br>(Ship no. 402)
|23 Jun, 1910
|25 Oct, 1911
|Jun, 1913
|Scuttled 12 Apr, 1924
|}
</div name=fredbot:ships>
==Radio==
According to the ambitions of 1909, these ships had [[Service Gear Mark II]] wireless upon completion.{{ARTS1908|Wireless Appendix, p. 13}}

==Searchlights==
{{UK-Indefatigable}} and {{AU-1Australia}}, at least, were fitted with Siemens' No. 3 Twin Mountings for 24-in projectors.  In 1914, some or all of these were to be modified to permit 90 degree elevation for use in anti-aircraft work.{{ARTS1914|p. 52}}

==Armament==

===Main Battery===
This section is sourced in ''The Sight Manual, 1916''.{{TheSightM|pp. 4, 34, 106, 108-109, Plate 10}}

The eight 12-in guns were Mark X mounted in B. VIII* turrets.   The mountings could elevate 13.5 degrees and depress 5 degrees.<ref>I assume the B. VIII* elevation is as in the B VIII</ref>

The gun sights were cam-worked sights limited to 15 degrees elevation.  

The deflection gearing constant was 67.75, with 1 knot equalling 2.42 arc minutes, calculated as 2700 fps with 4 CRH shells at 5000 yards.  Range drums were provided for 2 CRH projectiles at full charge at 2625 fps, reduced charge at 2250 fps, as well as 6-pdr sub-calibre gun and .303-in aiming rifles.  By some time in 1916, dials and drums were on hand for 4 CRH heads.

Muzzle velocity was corrected by adjustable scale plate.  An adjustable temperature scale plate could vary between 60 to 100 degrees Fahrenheit,{{FC}} and a "C" corrector could alter the ballistic coefficient by at least +/- 15% and possibly 20% as in other sights.{{FC}}

Drift was corrected by inclining the sight bracket by 3 degrees with a permanent correction of 2.07 knots left.

The side position sighting lines were 37.25 inches above and 38.25 inches abreast the bore, and the central scopes were 49.25 inches above and 42 inches abreast.  

The mountings had free trainers sights, though perhaps only in the centre position.

===Secondary Battery===
This section is sourced in ''The Sight Manual, 1916''.{{TheSightM|pp. 7, 89-90, 108, Plate 39}}

Sixteen 4-in B.L. Mark VII guns on P. II* mountings were arranged for broadside fire.  They were similar to the P. II and P. II* equipment fitted in the ''Bellerophon'' class, {{UK-1Neptune|f=p}} and other ships.

The mounting could elevate 15 degrees and depress 7 degrees, but though its sight could match the 15 degree elevation, the range dial was only graduated to 11.5 degrees (10,000 yards).

These cam-worked sights had range dials for 2750 fps, and 1-in and .303-in aiming rifles.  MV could be corrected by adjustable pointer through +/- 150 fps.

The range dial may have been 14 inches in diameter with markings that came closer together at higher ranges, as in the P II.  If so, the marks were {{frac|3|4}} inch apart for 50 yards difference at 500 yards and was {{frac|1|8}} inch for 50 yards difference at 9,000 yards.

Unlike some P. II* sights such as those on ''Neptune'', these sights were F.T.P. sights.

The deflection gearing constant was 64.277 with 1 knot equal to 2.41 arc minutes, corresponding to 2800 fps at 2000 yards.  Drift was corrected by inclining the sight 2 degrees.

The layer's sight line was 14 inches above the bore, and 15.25 inches left.  The trainer's sight line was 15.25 inches above and 12.5 inches right.

The sight had a temperature corrector, but not a "C" corrector.

The layer had an open sight.  The trainer's sight could be used as a [[Free Trainer's Sight|free sight]] with a counterweight.

In February, 1913, these mountings, along with many other 4-in and 6-in mountings in various capital ships and cruisers were to have illumination added for their training index racers.<ref>Admiralty Weekly Orders. {{TNA|ADM 182/4}}.  21 Feb, 1913 entries.  pp. 3-4.</ref>  In August of 1913, [[Portsmouth Royal Dockyard]] was to supply head rests for the guns in {{UK-Indefatigable}} and {{UK-NewZealand}}, to be fitted in the dockyard when the opportunity arose.  {{AU-1Australia}} was omitted from this order, presumably because she was on her Australian cruise.{{AWO1913|470 of 22 Aug, 1913}}

===Torpedoes===
* two 18-in submerged broadside tubes forward, depressed 3 degrees.{{UKAddenda1911TorpM1909III|p. 155}}
In 1909, it was decided that ships of this class were to carry 10 heater torpedoes.  The goal, when supplies were made good, was to have these be [[18-in R.G.F. Mark VI* Torpedo|Mark VI* H.]] or [[18-in R.G.F. Mark VI** Torpedo|Mark VI** H.]].{{ARTS1909|pp. 13-4}} 

In 1913, it was approved, as part of a general reallocation of 18-in torpedoes, to replace the torpedoes on these ships with Mark VII* or Mark VII** torpedoes.{{ARTS1913|p. 8}}

==Fire Control==

===Range Dials===
As of 1920, ''New Zealand'' had two [[Range Dial Type B]]s and a single [[Range Dial Type C|Type C]].  ''Australia'' had a single Type B and a single Type C.{{UKManGun1920III|p. 44}}

===Rangefinders===
''Indefatigable'' was completed in the same form as the ''Invincibles'' with two 9-ft rangefinders, one in each control top.  The delay in bringing ''Australia'' and ''New Zealand'' along permitted them to incorporate a new wrinkle:  a third 9-ft rangefinder added atop "A" turret.  ''Indefatigable'' received her "A" turret rangefinder during a refit between 1911 and 1914.{{RobertsBattlecruisers|pp. 90-91}}

Rangefinders were added to the echelon turrets by at least 1917 when photos depict them on ''Australia''.{{RobertsBattlecruisers|Photo page 30}}  ''Australia'' had a small one on her after super structure, but ''Indefatigable'' did not.{{Burt1986|p. 98}}

Sometime during or after 1917, an additional 9-foot rangefinder on an open mounting was to be added specifically to augment torpedo control.{{ARTS1917|p. 198. (C.I.O. 481/17)}}

===Evershed Bearing Indicators===
Only ''Indefatigable'' is explicitly mentioned in ''Handbook for Fire Control Instruments, 1914'',{{HFCI1914|pp. 33-9}} but the other ships were approved to receive equipment in 1916 (see their ship pages).

The transmitting positions for ''Indefatigable'' were 
* Fore control platform (transmitters to port and starboard with a local switch to select one in use)
* "A" turret
* "X" turret
* Upper aft conning tower

The protocols for how her crew should handle [[Wooding|wooding]] of the turrets was outlined in the ''Handbook for Fire Control Instruments, 1914''.{{HFCI1914|p. 36}}

In 1917, it was approved that capital ships of [[H.M.S. Dreadnought (1906)‎|''Dreadnought'' class]] and later should have Evershed equipment added to their {{CT}}, able to communicate with either the fore top or a control turret.  If there were not enough room in the C.T., a bearing plate with open sights and 6-power binoculars would be added to the C.T..  At the same time, all directors were to be fitted with receivers and, "as far as possible", ships were to have fore top, {{GCT}} and controlling turrets fitted to transmit as well as receive, though this was noted as being impossible in some earlier ships.{{ARTS1917|p. 230}}

===Mechanical Aid-to-Spotter===
At some point, ''Australia'' and ''New Zealand'' were equipped with a pair of [[Mechanical Aid-to-Spotter Mark I]]s, one on each side of the foretop, keyed off the Evershed rack on the director.  As the need for such gear was apparently first identified in early 1916, it seems likely that these installations were effected well after Jutland.{{FCHMShips|pp. 25-6}}

In 1917, it was decided that these should have mechanical links from the director and pointers indicating the aloft Evershed's bearing.{{ARTS1917|p. 230}}

===Gunnery Control===
The control arrangements were likely as follows.{{HFCI1914|pp. 7-8. (some inferences drawn due to fundamental differences between this design and that of ''Orion'' to which it is likened)}}

====Control Positions====
* Fore top
* Main top (''Australia'' lacked one){{INF}}
* "A" turret{{INF}}
* "Y" turret{{INF}}

Some ships had C.O.S.s within the control positions so they could be connected to either T.S..{{HFCI1914|p. 7}}

====Control Groups====
The four 12-in turrets were separate groups, each with a local [[C.O.S.]]{{INF}} so that it could be connected to 
* Forward T.S. 
* After T.S. 
* Local control from officer's position within turret 

===Directors===

====Main Battery====
The ships were fitted with a tripod-type director in a light aloft tower on the foremast below their forward control top along with a directing gun in the Y turret.{{DirectorH|pp. 88, 142}}{{Burt1986|p. 98}}  The battery was not divisible into for split director firing.{{DirectorH|p. 88}}

The turret [[Elevation Receiver]]s were pattern number H. 2, capable of matching the 13.5 degree elevation limit of the mountings.  The [[Training Receiver]]s were the [[Single Dial Turret Training Receiver|single dial type]], pattern number 7.{{DirectorH|pp. 144, 146}}

====Secondary Battery====
The 4-in broadside guns are not listed as ever having had directors before the war's end,{{DirectorH|pp. 143}} but in July, 1922, {{AU-1Australia}} apparently had director firing for her secondary battery, as spares were ordered to be set aside for her.<ref>Admiralty Fleet Order 1832/1922.  (G. 2475/22.&mdash;7.7.1922)</ref>

===Torpedo Control===
By the end of 1917, common torpedo control additions to all capital ships were to be adopted where not already in place.  Those for ''Dreadnought'' and later classes with 18-in tubes were to include:{{ARTS1917|p. 209.  (C.I.O. 4212/17.)}}
* duplication of firing circuits and order and gyro angle instruments to allow all tubes to be directed from either {{CT}} or {{TCT}}
* navyphones from both control positions to all tube positions
* bearing instruments between "control position, and R.F., and course and speed of enemy instruments where applicable, between the transmitting stations and the control positions."
* range circuits between R.F.s and control positions

===Transmitting Stations===
Like all large British ships of the era prior to [[H.M.S. King George V (1911)|''King George V'']] and [[H.M.S. Queen Mary (1912)|''Queen Mary'']], these ships had 2 [[T.S.]]es.{{HFCI1914|pp. 6-7}}

===Dreyer Table===

As of 1918, the ''New Zealand'' and ''Australia'' carried Mark I Dreyer tables{{DreyerH|p. 3}}.  As to time of installation, one secondary source asserts that ''Indefatigable'' and ''New Zealand'' had Mark I tables at the [[Battle of Jutland]],<ref>Sumida, Jon. ''In Defence of Naval Supremacy'' p. 300.</ref> but no primary source confirms this.  Moreover, a first-hand account seems to suggest a manual plotting board was being used in the T.S. of ''New Zealand''.<ref>Midshipman Gordon Eady quoted in Steel & Hart.  ''Jutland 1916'', p. 75.</ref>

The ships were never given [[Dreyer Turret Control Table]]s.{{DreyerH|p. 3}}

===Fire Control Instruments===
The ships used [[Vickers]] {{FTP}} Mark III range and deflection instruments to send data to gun sights (likely with cross-connected Mark III* range transmitters{{ARTS1910|p. 148}}), retaining [[Barr and Stroud]] (probably Mark II*{{INF}}) instruments for other destinations.{{HFCI1914|pp. 72}}

''Target Visible'' and ''Gun Ready'' signals mounted in the TSes and control positions indicated which turrets could see the target and which guns were ready.{{HFCI1914|p. 11}}

==See Also==
{{WP|http://en.wikipedia.org/wiki/Indefatigable_class_battlecruiser}}
*[http://dreadnoughtproject.org/models/ships/HMAS_Australia/ 3D Model] of ''Australia'' available for licensing

==Footnotes==
{{reflist}}

==Bibliography==
{{refbegin}}
*{{FCHMShips}}
*{{DirectorH}}
*{{DreyerH}}
*{{SumidaIDNS}}
*{{BrooksDGBJ}}
*{{RobertsBattlecruisers}}
*{{SteelHartJutland1916}}
{{refend}}

{{Footer Indefatigable Class Battlecruiser (1909)}}

{{DEFAULTSORT:Indefatigable}}

{{CatClassBattlecruiser|UK}}


<!-- data

nat=UK
cat=Battlecruiser
type=battlecruiser

chain=Major Cruisers

{ship
name=Indefatigable
pend=13 (1914){{DittColl|p. 35}}
builder=[[Devonport Royal Dockyard]]{{Conways1906|p. 26}}
order=1908 Programme{{Conways1906|p. 26}}
laid=23 Feb, 1909{{Conways1906|p. 26}}
launch=28 Oct, 1909{{DittColl|p. 35}}
comm=1911{{Conways1906|p. 26}}
fate=Sunk
fate2=at the [[Battle of Jutland]]
fatedate=31 May, 1916{{DittColl|p. 35}}
}

{ship
name=New Zealand
pend=08 (1914)<br>90 (Jan 1918)<br>53 (Apr 1918){{DittColl|p. 35}}
builder=[[Fairfield Shipbuilding and Engineering Company]], Govan{{Conways1906|p. 26}}
order="
laid=20 Jun, 1910{{Conways1906|p. 26}}
launch=1 Jul, 1911{{DittColl|p. 35}}
comm=1912{{Conways1906|pp. 26-7}}
fate=Sold
fate2=Scrapped
fatedate=19 Dec, 1922{{DittColl|p. 35}}
}

{ship
name=Australia
nat=AU
prefix=H.M.A.S.
pend=C6 (Feb 1915)<br>09 (Jan 1918)<br>81 (Apr 1918){{DittColl|p. 35}}
builder=[[John Brown & Company]], Clydebank<br>(Ship no. 402){{JohnstonClydebankBattlecruisers|Footers}}
order="
laid=23 Jun, 1910{{Conways1906|p. 26}}
launch=25 Oct, 1911{{DittColl|p. 35}}
comm=Jun, 1913{{Conways1906|p. 26}}
fate=Scuttled
fate2=off Sydney{{DittColl|p. 35}}
fatedate=12 Apr, 1924{{DittColl|p. 35}}
}



data -->

[[Category:Featured Ship Classes]]