Mark 49 Gun Director

Documents | Gallery | Data Tables

In the years leading up to the second world war, many countries grappled with the problem of making anti-aircraft fire more accurate. The speed of an aircraft, plus its distance from a gun meant that if a gunner simply put the sites directly on the plane and fired, the shells would always fall behind the aircraft and miss. Additionally, smoke and vibration from the gun could make the target harder to see and follow.

The solution that many world navies chose was a gun director, mounted near the gun, that could accurately determine range, vector, and speed. Early units were purely optical in nature, but by the end of the war state-of-the-art included radar powered units that could control multiple gun mounts at once.

The Mk 49 director was a short-lived anti-aircraft fire director used on some US warships in the middle to late phase of World War II. It was a replacement for the earlier Mk 45, which had turned out too large, heavy, and complex for most shipboard installations. The Mk 49 itself, however, suffered from high complexity and maintenance needs itself, and the success of the simpler Mk. 51 design caused its withdrawl starting in October of 1943.

Unlike the Mk 51, wherein the operator stood behind a pedestal-mounted unit and aimed it by turning and tilting with his arms and body, the operator sat inside an enclosed ball with an opening at the top front. Entry was through a hatch on the top rear, and once energized the ball portion would rotate on two axis for train and elevation. Originally designed to be used with the 1.1" mounts early in the war, they were mainly used with the twin and quad 40mm anti-aircraft mounts that replaced the quad 1.1" mounts in 1942.

The one advantage the Mk 49 had over the Mk 51 was that radar could be mounted, allowing for directing during attacks within periods of night time or low visibility. For this reason, radar equipped units were kept on some larger ships until later in the war, when newer systems such as the Mk 57 and 63 came online. The radar, when mounted, was always to the right of the operator on the side near the pivot point. Two types of radars were carried although for all practical purposes they would be indistinguishable in conventional ship modeling scales.

Schematics for the Mk 49 have not, at this time, been located, but some details are known from the textual records which have been located. If a Mk49 was to be encased in a splinter-shielded tub, minimum diameter of 6', was called for, and it was to be built in segments to facilitate maintenance. The maximum height for the tub was 3' to allow the Mk 49 to depress enough to be used during periods of moderate rolling.

Nearly 350 were delivered before installations were halted in October of 1943. The first 269 were built without radar, nearly 50 with the Mk 11 radar, and an unknown number, possibly the balance (roughly 30), with the Mk 19 radar. A November 1944 Bureau of Ordnance letter stated that ships had been authorized to replace the Mk 49 with the Mk 51 and that all directors no in use afloat or in shore activities (training facilities for the most part) should be scrapped.

Once the viewer is familiar with the "R2D2" is appearance of the Mk 49 and the locations they were normally mounted, it is generally not too difficult to locate them and differentiate between somewhat similar sillouettes such as searchlights. Below is a gallery of photos showing some of the variations of the unit and installations, as well as lists of ships that we know carried the Mk 49. When specific dates are known for the installation or removal they are given, or a specific date that we know that they were at least present; the modeler or research may use yard visits to guess at the installation and removal dates in some cases.

Schematics have not been located at this time, but thanks to the help of others we know that the mount's working circle was 8-ft, 2-in and Max overall height was 6-ft, 11-in. There were six different versions, used for different purposes and with different characteristics:

Mk 49 Mod 1 440 VAC (Used on quad 1.1" guns)
Mk 49 Mod 2 230 VDC (Used on quad 1.1" guns)
Mk 49 Mod 3 115 VDC (Used on quad 1.1" guns)
Mk 49 Mod 4 440 VAC (Used on twin or quad 40mm guns)
Mk 49 Mod 5 230 VDC (Used on twin or quad 40mm guns)
Mk 49 Mod 6 115 VDC (Used on twin or quad 40mm guns)

If you have any corrections or additions, please contact the webmaster of this site or Tracy White.

  Documents:

Image Gallery 
- Click for Full Size -
Close-up shot showing basic components of Mk 49 director including enclosed operator compartment and and Mk 19 radar antenna. Both the Mk 11 and Mark 19 radars were used.
USS New Jersey (BB-62) at the Philidelphia Navy Yard on October 29, 1943. Port side looking forward towards armored conning tower.
Photo from the records of Puget Sound Naval Shipyard, Seattle NARA.
Photo from the rear of the Mk 49 showing the operator's seat and controls. Note that this version has both the optical site and a radar; early versions lacked the radar unit and sites that the later ones possesed. Navy documentation in late 1943 indicated that the optical-only units were no better than the alternative Mk 51s and required much more maintenance; the only advantage the Mk 49 had was in nighttime and low-visibility environments when the radar was installed.
Photo from the records of Puget Sound Naval Shipyard, Seattle NARA.
Stern installations of unknown version of Mk 49 aboard BB-56 Washington, August 1942. These units may have been outfitted with optical range finders on the sides, or perhaps they are gyros.
Official USN Photo from photo files at NARA II.
Source: Rick E. Davis
Midships installation on BB-38 Pensylvania, May 1943, looking astern from forward superstructure.. Pennsylvania carried these Mk 49s during her actions in the Aleutians campaign at Holtz Bay and Chicago Harbor, Attu.
Official USN Photo from photo files at NARA II.
Source: Rick E. Davis
Gleaves-class destroyer USS Bristol (DD-453) on 7 January 1943 after she received the two twin 40mm AA mount upgrade. View is looking aft on the starboard side. Note the crewmen in and next to the director for scale purposes, as well as the absence of radar seen in the above photos.
Photo from the photo files at NARA.
Source: Rick E. Davis
Fletcher-class destroyer USS Caperton (DD-650) on 15 August 1943 at Boston Navy Yard. She was completed with three Mk 49 directors controlling the aft three twin 40-mm mounts and two Mk 51 directors in the bridge wings controlling the two forward twin 40-mm mounts.
Official USN Photo from the BuShips photo files at NARA (19-N-).
Source: Rick E. Davis
USS Trathen DD-530 near Mare Island August, 1943. Three Mk 49s without radar are present.
Photo from NARA San Francisco "Mare Island Naval Shipyard Ship Files"
Close up of aft Mk 49 on DD-530 with twin 40mm mount the day prior to the above picture. Note lack of radar on this earlier unit, sliding plexiglass windscreen, and open access hatch on the pedastal. View is looking aft and to starboard.
Official USN Photo from the BuShips photo files at NARA (19-N-).
Source: Rick E. Davis
USS Hall (DD-583) a Boston Navy Yard built unit on 4 August 1943, is one of the earliest photos found with the radar (Mk 11 or Mk 19, but probably Mk 11) installed. This is about as close-up a view as has been found so far on a Fletcher.
Photo from the BuShips photo files at NARA (19-N-).
Source: Rick E. Davis
USS Cotten DD-669 with two oh her Mk 49s in view on the aft stack. Not that the radar is in the same side of the unit regardless of what side of the ship the unit is mounted. Not too, that the reflector dish is solid, likely making this the earlier Mk 11 variety of radar.
Photo from the BuShips photo files at NARA (19-N-).
Source: Rick E. Davis
Forward installation of a Mk 49 and radar on CV-16 Lexington, December, 1944. This mount was installed right on top of the bridge pilot house and controlled the mount to the right of it in the photo.
Official USN Photo from RG 80-G at NARA II.

DATA TABLES: 

The "Verified Install Dates" at this point are dates we have photographic evidence that a director was present. If we have records that indicate install and removal dates that will be noted.

Aircraft Carriers | Battleships | Cruisers | Minelayers | Destroyers

Aircraft Carriers 

Essex Class
Ship # of Mk. 49s Installed Known dates:   Removed
CV-9 Essex 2 (above Bridge & between aft island 40mms Commissioned   ~March 1944;
CV-11 Intrepid 1 (Behind #2 twin 5" mount & between aft island 40mms) Commissioned  - after shakedown?
CV-16 Lexington 2 (Above Pilot House and ???) Commissioned - until April-May '45 Overhaul

Battleships 

Pennsylvania Class
Ship # of Mk. 49s Installed Known dates:   Removed
BB-38 Pennsylvania 2 January, 1943 June?/July? 1943

Tennessee Class
Ship # of Mk. 49s Installed Known dates:   Removed
BB-43 Tennessee 2 (inboard #3 & 4 twin 5" mounts) January, 1943 - ?? Before Jan, 1944

South Dakota Class
Ship # of Mk. 49s Installed Known dates:   Removed
BB-60 Alabama 2 (One Above bridge, port,
On aft, stbd stern quad 40mm)		 Commisioned

Iowa Class
Ship # of Mk. 49s Installed Known dates:   Removed
BB-61 Iowa 4? ? ? ?
BB-62 New Jersey 4 ? October, 1943 ?

Cruisers 

Omaha Class
Ship # of Mk. 49s Installed Known dates:   Removed
CL-4 Omaha 2 February, 1943  
CL-12 Marblehead ? October, 1942  

Northampton class
Ship # of Mk. 49s Installed Known dates:   Removed
CA-29 Chicago 2 (stbd superstructure, port stack) December '42 lost with ship, Jan 30, 1943

New Orleans Class
Ship # of Mk. 49s Installed Known dates:   Removed
CA-34 Astoria >=2   June '42  
         

Cleveland Class
Ship # of Mk. 49s Installed Known dates:   Removed
CL-60 Santa Fe 2  

Baltimore Class
Ship # of Mk. 49s Installed Known dates:   Removed
CA-68 Baltimore 2 February, 1943
     
     
     

Minelayers 

Terror Class (Mk 45s)
Ship # of Mk. 45s Installed Known dates:   Removed
CM-5 Terror 2 (above bridge [Mk45s?])   Operation Torch  

Destroyers 

Farragut class
Ship # of Mk. 49s Installed Known dates:   Removed
DD-348 Farragut 2   December, 1943  
DD-350 Hull 2  ? May, 1944 August-November, 1944
DD-351 MacDonough 2   Jan-Sept, 1943  

Benson/Gleaves class
Ship # of Mk. 49s Installed Known dates:   Removed
DD-433 Gwin 2   16 February 43 @ MINY
DD-453 Bristol 1 + one Unk   7 January 1943
DD-607 Frazier 2   5 August 1943 … Mk 51's by 26 September 1943
DD-626 Satterlee 2   22 September 1943
DD-628 Welles 2   10 November 1943
DD-638 Herndon 2   30 March 1943
DD-639 Shubrick 2   24 March 1943
DD-641 Tillman 1 + one Mk 51   14 August 1943
DD-647 Thorn 2   30 March 1943 & 28 May 43 … Mk 51's by Jan 44
DD-648 Turner 2   April 1943 & 23 August 43 … ship Lost 2 Jan 44

Fletcher class
Ship # of Mk. 49s Installed Radar(s) Removed
DD-465 Saufley 1 September 1942 None September 1944
DD-466 Waller 1 November 1942 None September 1944
DD-470 Bache 1 December 1942 None November 1944
DD-473 Bennett 3 March 1943 None November 1944
DD-474 Fullam 3 March 1943 None About September 1944
DD-513 Terry 1 January 1943 None November 1944
DD-514 Thatcher 1 February 1943 None About November 1944
DD-515 Anthony 1 February 1943 None November 1944
DD-516 Wadsworth 3 March 1943 None November 1944
DD-517 Walker 3 April 1943 None About January 1945
DD-519 Daly 3 March 1943 None About January 1945
DD-520 Isherwood 3 April 1943 None Before August 1944
DD-521 Kimberly 3 May 1943 None Before October 1944
DD-522 Luce 3 June 1943 Two Mk 11s, September 1943 About August 1944
DD-527 Ammen 1 March 1943 None Between Jun '44 and Jan '45
DD-528 Mullany 1 April 1943 None May-June 1945
DD-529 Bush 3 May 1943 None Before June, 1944
DD-530 Trathen 3 May 1943 None About November, 1944
DD-531 Hazlewood 3 June, 1943 None May-June 1945
DD-533 Hoel 3 July, 1943 None Before August, 1943
DD-534 McCord 3 August, 1943 None About July, 1945
DD-535 Miller 3 August 1943 Two Mk 11/19s, Sept 1943 After Feb, 1945
DD-537 The Sullivans 3 Spetember, 1943 None About December, 1943
DD-544 Boyd 1 May, 1843 None Before January, 1944
DD-546 Brown 3 July, 1943 None ??
DD-550 Capps 3 June, 1943 Three Mk 11, August 1943 Before March, 1944
DD-551 David W. Taylor 3 September, 1943 Two Mk 11/19, Oct 1943 ??
DD-554 Franks 3 July, 1943 Unknown Between October-December, 1943
DD-556 Hailey 3 Septmeber Two Mk 11/19, Oct 1943 ??
DD-575 McKee 3 March, 1943 None Before December, 1944
DD-576 Murray 3 April, 1943 None  About November, 1944
DD-577 Sproston 3 May, 1943 None ??
DD-580 Young 3 Juy, 1943 Two Mk 11/19, August 1943 Before September, 1944
DD-581 Charrette 3 May, 1943 Two Mk 11 After February, 1945
DD-582 Conner 3 June, 1943 1/2 Mk11/19 ??
DD-583 Hall 3 July, 1943 2 Mk 11, August, 1943 December 1943
DD-587 Bell 3 March, 1943 None ??
DD-588 Burns 3 April, 1943 1/2 Mk 11, August, 1943 ??
DD-589 Izard 3 May, 1943 2 Mk11, September, 1943 ??
DD-630 Braine 3 May, 1943 None ??
DD-642 Hale 3 June, 1943 2/3 - Mk 11/19
- September 1943		 ??
DD-644 Stembel 3/2 July, 1943 None 2 in 1944
DD-650 Caperton 3 July, 1943
August 1943		 2, then 3 Mk 11
by August 1943		 1945??
DD-657 Charles J. Badger 3 July 1943 2 Mk 11, August, 1943 ??
DD-659 Dashiel 1 March, 1943 None After January, 1944
DD-667 Chauncey 3 May, 1943 None About 1944
DD-669 Cotten 3 July 1943 2 Mk11, August, 1943 ??
DD-671 Gatling 3 August, 1943 2 Mk 11/19, September, 1943 ??
DD-673 Hickox 3 September, 1943 2 Mk 11/19 October, 1943 ??
DD-674 Hunt 3 September, 1943 None October, 1943
DD-675 Lewis Hancock 3 September, 1943 2 Mk19, October, 1943 ??
DD-681 Hopewell 3 September, 1943 2 Mk19, October 1943 ??
DD-685 Picking 3 September, 1943 None ??
DD-688 Remey 3 September, 1943 2 Mk11/19, October, 1943 ??

Additional Resources
"Operational Characteristics of Radar Classified by Tactical Application" - Navy History & Heritage Command
The Mechanical Analog Computers of Hannibal Ford and William Newell- PDF
Interview of Ivan Getting, MIT - PDF

Special Thanks to:
Rick E. Davis
AD Baker
Ron Smith