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USS Oklahoma CIty CLG-5 (1971) 3D CAD model

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This tower originally carried a radar antenna, but it was removed to reduce topside weight. The basic structure was similar to the forward radar tower.





The tower rested upon the top of the O3 level radar room. Well, it was a radar room while the 3D radar antenna was on the tower, but after the antenna and associated radar equipment were removed the compartment became an office with very good heating and air conditioning. The large vent stack on the starboard side of the compartment was Charlie Noble. The arms extending from the deck house sides were the rests for the stowed boat booms.




The platform at the top of the tower carried four 35 foot whip antennas and a few other smaller antennas. A short stub mast carried the ship's Tactical Air Navigation (TACAN) antenna in the dome. It was used by helicopters to determine the range and bearing to the ship. It was also used by other ships to facilitate rendezvous. Another mast at the forward edge of the platform carried a few more antennas and the ship's AN/URD-4 radio direction finder at the top that was used for search and rescue operations. This mast was hinged about half way up so it could be folded sideways. There were a few bridges the ship might have to pass under that were lower than the raised mast.



Edited by Dr PR

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The ship had a good collection of small boats even after the weight reduction measures that eliminated two of the 40 foot utility boats. In addition to the ship's complement of four boats, when the ship served as 7th Fleet flagship it carried two additional boats on portable cradles atop the missile house (described later). Plans for most of the Navy's small boats and auxiliaries that were used in the mid 20th century are available from the Barbour Boat Works Inc. records (#758) at the J. Y. Joyner Library at East Carolina University, Greenville, North Carolina, USA. https://digital.lib.ecu.edu/11208


40 Foot Personnel Boat Mk 4



This boat was used to ferry personnel from ship to shore or to other ships.


40 Foot Utility Boat Mk 2





The utility boat was used for many things. We used it to carry the crew to shore for liberty and to bring back personal belongings that were purchased in places like Hong Kong. The center benches folded to make room for large cargo.


26 Foot Motor Whaleboat Mk 10



The whaleboat was used to carry personnel and mail between ships and to shore. It was also launched during man overboard drills - and the real thing - to fish people out of the ocean.


28 Foot Personnel Boat Mk 6 Captain's Gig



This boat was assigned to the USS Oklahoma City, and served as the Captain's gig.




28 Foot Personnel Boat Mk 6 Admiral's Barge




While the 7th Fleet staff was aboard the ship carried the Admiral's Barge on a portable boat cradle . It was stowed on top of the missile house aft. It was tricked out with more details and chrome than the other boats.



28 Foot Personnel Boat Mk 6 7th Fleet Staff Boat



The 7th Fleet Staff Boat was used by the Chief of Staff and other 7th Fleet officers - there were lots of them! It was tricked out better than the Captain's Gig, but not quite as nice as the Admiral's Barge. It was also stowed on a portable boat cradle aft on the missile house.



The portable boat cradle was another challenge. I have found no plans but I do have several good photos of the cradles used on the OK City. The ship had two snaking winches on the missile house that were used to drag things around. They were used to move the boat and cradle from the stowed position on the after part of the missile house top to the forward part of the missile house top where the boats could be lowered and raised using the boat booms.




Edited by Dr PR

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For the CLG conversion everything above the main deck aft of the midships superstructure was removed. The triple 6"/47 turrets #3 and #4, dual 5"/38 gun mounts #54, #55 and #56, the aft Mk 34 and Mk 37 directors and the deck houses around them, and the aircraft catapults and crane were scrapped. In their place a huge armored missile house was built on the main deck and a new after superstructure and tower were built on top of the missile house. The entire after deck house was part of the Talos guided missile launching and guidance system.





missile launcher.jpgThe missile house contained the Mk 7 Guided Missile Launching System where the missiles were stored and serviced. The house was made of 1 1/2" Special Treated Steel (armor plate). Including 46 Talos missiles and boosters the house added 400,000 pounds on the main deck. This didn't help stability problems!


Missiles were prepared for launching inside the house and then moved onto the Mk 7 launcher rails, passing through armored blast doors in the end of the house. The upper doors carried spanner rails to mate the launcher rails to the launching system rails inside the house.


For more information about the Talos launching system go to this link: https://www.okieboat.com/Talos launching system.html


aft superstructure 2.jpgThe deck house on top of the missile house contained Weapons Control, where the Talos system was operated, and radar rooms for the SPS-30 3D height finder radar, the two massive AN/SPG-49 missile tracking radars and the two AN/SPW-2 guidance transmitter antennas.


Talos was a long range (130 nmi.) Mach 2.7 missile designed to intercept aircraft and missiles at altitudes from 50 feet to 75,000 feet. It had an anti-surface ship capability, and an anti-radiation (radar) ARM capability. For these missions it carried a conventional expanding rod warhead. It also had a 2 KT nuclear warhead that could be used against air, surface and shore targets.  For more information aout the Talos missile see: https://www.okieboat.com/Talos missile.html


Talos was the first anti-aircraft missile system designed by the US Navy, beginning in 1945 before the end of WWII. The program actually spun off the shorter range Terrier missile which was the first to enter service. Talos was a massive system that was installed on only a few cruisers. It was replaced by the newer AEGIS missile system.


You can see the stowage locations for the two 7th Fleet 28 foot personnel boats and their cradles.









There were two of these little snaking winches, port and starboard,  that were used to haul the 28 foot personnel boats and carriages around the top of the missile house. It was the smallest of the ship's winches, with just an electric motor and gear system and no hydraulics. I modeled it from photos and dimensioned sketches made on the USS Little Rock CG-4 museum ship.


It was also used to transfer missile warheads into the missile house through hatches in the deck at the rear of the missile house.









The after radar tower was much simpler than the other two towers. It was positioned above the radar room for the AN/SPS-30 3D height finder and air search radar. In addition to the SPS-30 antenna an AS-791/UPA-43 Identification Friend or Foe (IFF) interrogator antenna (below left) was mounted on a platform wing. It was slaved to the SPS-30 to allow IFF interrogation of targets.  An AS-979A/UKR telemetry antenna (below right) was mounted on a platform extension at the rear of the tower platform. I think (but I am not certain) that this was the antenna used to receive telemetry information from Talos missiles in flight. The missiles sent back airspeed, altitude, fuel consumption, wing motion and radar proximity fuze information to allow analysis of the flight.



On the ship's centerline on top of the forward end of the missile house was a large contraption called the Fleet Active Shuttle Transfer (FAST) crane (below). It was designed to operate with similar equipment on replenishment ships to transfer Talos missiles to the OK City's missile magazine. It was capable of transferring a missile or booster every 90 seconds. The operator worked in a small booth at the aft end of the midships superstructure on the O3 level.



Missiles would arrive on a shuttle that rode a highline strung between the FAST crane and the FAST system on the replenishing ship. The missiles and boosters were attached to strongbacks carried by the shuttle. The FAST crane would capture the shuttle and strongback, A pantograph arm on the FAST crane lowered the strongback and missile/booster into position above a strikedown elevator (yellow in the images above). The elevator captured the missile and the strongback was released. Then the missile was lowered into the magazine at the forward end of the missile house. The pantograph arm raised and sent the strongback and shuttle back for another load.


That's the way it was supposed to work. In reality the FAST crane was a piece of junk. It was exposed to the worst of weather conditions and the complex hydraulic and electrical system failed during transfers more often than not. The real problem was not with the machinery - the Navy did not have enough trained personnel to maintain it. Many complex systems were introduced into the navy in the 1950s and 1960s - nuclear submarines, nuclear powered ships, nuclear weapons, sub launched ballistic missiles, surface to air missiles, jet aircraft with complex avionics systems, air to air and air to surface missiles, and many new types of radars. There were not enough intelligent people joining the Navy and not enough training facilities to train them. First priority went to nuclear submarines and the air wings. There was a chronic shortage of trained personnel on all other units. We just didn't have enough trained men on the OK City to maintain the missiles, launching system, radars, guns and other systems to spare anyone to baby sit the FAST system.


The FAST crane was removed in late 1971 and only the kingpost at the center remained. We used the FAST kingpost and burtoning winch for underway replenishment of missiles and powder for the guns. The FAST crane is the reason I decided to model the ship as it was in the summer of 1971, just before the FAST crane was removed. I wanted to model it.



Edited by Dr PR

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The ship carried a collection of radars. I have data sheets and drawings for most of them, and the service manual for the AN/SPS-10. Each antenna was a model unto itself.


AN/SPS-10 Surface Search Radar




The SPS-10 was the primary surface search radar, used to detect ships and low flying aircraft and missiles. On the OK City the horizon was about 13 miles at the height of the SPS-10 antenna. The 1642791908_AN-SPS-103.jpg.ef98b8664831d416d46a5462a08002bf.jpgradar could track targets above the horizon out to about 100 miles. It was very sensitive when tuned properly. On one occasion we tracked flocks of birds a mile or two away. On another occasion when we had excellent atmospheric "tunneling" over the horizon I tracked an aircraft carrier at Yankee Station in the Gulf of Tonkin at a distance of 65 miles. The SPS-10 operated at 5.42 to 5.825 GHz with a 285 kW peak power.


The antenna carried a AN/UPX-27 Identification Friend or Foe (IFF) dipole on the "spider" arm that held the feed horn. This is the rod with the square kink in it, and the surrounding reflector rods. 



Pathfinder Navigation Radar





We had a Raytheon Pathfinder radar for navigation in harbors and channels. The SPS-10 had a minimum range of about a mile or so, and couldn't detect close in objects. The Pathfinder was good down to very short distances.


This is a very sketchy illustration. I have no data sheets or drawings and only a few fuzzy photos to work from. Some day I will have better information and will be able to make a more accurate model.





AN/SPS-43 Air Search Radar


The SPS-43 was the primary air search radar. It had an effective range out to 300 miles for high flying planes and missiles. The minimum range for low flying planes was limited by the horizon. In Vietnam I used the 43 to track B-52 flights from Thailand to targets in North Vietnam. The huge slab sides of the B-52 were "anti-stealth" - they showed up as large bright blips on the radar screen. They were called "Arc Light" missions for good reason!



The "bed spring" reflector had a "W" shape cross section behind an array of  ten pairs of dipole antennas fed by a complex coaxial transmission line system with power dividers to feed each pair of dipoles the same amount of radiated power. The SPS-43 operated in the VHF band at 200 MHz with 180 kW peak output.


I finally found a few high resolution photos to allow me to work out the details of the antenna and support pedestal.


The short rectangular antenna at the top is an AT-352/UPA-22 IFF Interrogator antenna.





AN/SPS-30 3D Height Finder Radar


1891896233_SPS-302.thumb.jpg.1d5b48ebf1ca265971617585059bc9a7.jpgThe SPS-30 was an air search radar that had altitude detection capabilities. Altitude information from the 30 was fed into the missile guidance computers for intercept calculations. The SPS-30 also served as a secondary air search radar. An AS-791/UPA-43 IFF Interrogator antenna located on the aft radar tower platform was slaved to the SPS-30.











































The SPS-30 had a large oval parabolic dish reflector. In front of the reflector, at the end of the long support arm, was an "organ pipe" scanner. A waveguide connection in the scanner rotating at 240 to 2400 RPM fed the RF energy into twenty parallel vertically stacked waveguides leading to the feedhorns. Each feedhorn radiated RF energy at a slightly different angle to the reflector, resulting in 20 different beams reflected at different elevations. Returning signals from a target reflected off the dish into the respective feed horn, allowing the system to determine the vertical angle from the antenna to the target. From this angle and the range to the target the elevation was calculated.


The antenna could be rotated for air search operation or it could be aimed to track a single target. The entire rotating antenna dish and support arm could be elevated to track targets through a wide range of elevations. The mechanisms of the antenna were supported on a pedestal that had a gimbal system to compensate for roll and pitch of the ship to keep the antenna aimed at the target being tracked. Dual electric motors positioned the antenna for roll and pitch compensation. The SPS-30 operated in the S band from 3.4 to 3.6 GHz with a peak output power of 2.5 megawatts. It had an effective range of 240 miles.


AN/SPG-49 Missile Tracking Radar


The ship carried two SPG-49 tracking radars. The SPG-49 was a 19 feet high, 17 feet wide, 22 ton monster. The 49s had C band monopulse tracking radars and continuous wave (CW) illumination radars combined into the one antenna. The system performed three functions. During target acquisition the antenna radiated 3 megawatt pulsed bearing and azimuth sweeps to determine range, bearing and altitude of a target. After the target had been acquired the antenna switched to a pulsed 3 megawatt narrow beam tracking radar. When a missile closed range to a target the antenna also radiated a 5 kilowatt CW illumination beam that carried target identification information for the missile to home on.  All of the transmitters and receivers were housed inside the antenna shell.



The mechanism consisted of four assemblies. The truncated cone base was mounted on the ship with an accuracy of +/- 0.035 inch vertical relative to the axis of the missile launching system. The base contained a hydraulic drive to rotate the "U" shaped yoke around the vertical axis on the base. The yoke carried dual electric motors to drive the gimbal that rotated around the horizontal axis. The antenna housing rotated around the vertical relative to the gimbal by two sets of dual electric drive motors. A coarse bearing was maintained by the rotation of the yoke, but the motors on the gimbal allowed the antenna housing to be rotated side to side quickly and with better precision.






The antenna carried a closed circuit television camera that was used for antenna alignment. It could also be used to track short range targets visually. The Talos missile had a range of 130 nmi and the SPG-49 had a maximum range of 150 nmi. Tracking information from the 49s fed the missile guidance computer for calculation of the intercept position. For more details of the SPG-49 construction and operation use this link: https://www.okieboat.com/SPG-49 description.html


AN/SPW-2 Missile Guidance Radar


The ship carried two SPW-2 "radars." The SPW-2 wasn't exactly a radar. It transmitted a narrow guidance beam that the beam riding Talos missile followed. The missile guidance computer calculated an intercept point ahead of the target position and used the SPW-2 to drive the missile to the intercept point. The missile transmitted position and identification signals that the SPW-2 received. The received signals from the missile fed the guidance computer to track the missile.



The SPW-2 had a small optical telescope that was used for alignment. It also had a platform on top that could carry a closed circuit television camera, but we didn't have the TV cameras on the SPW-2s while I was aboard. The television camera could be used for alignment and to visually track the missile in flight at close range.


Mk 25 Gun Fire Control Radar


The Mk 25 electronics were housed in the Mk 37 gun director, with the antenna on top. It was used to determine bearing, elevation and range to targets that were engaged with gunfire. For direct fire missions with visible targets it tracked the target. For indirect fire missions with targets hidden behind hills it tracked a known point on land for reference in calculating the range and bearing to the target.


The Mk 25 operated from 5.2 to 10.9 GHz with a peak power output of 50 KW. It could track targets out to 50 nmi.





Edited by Dr PR

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That's all for now. Someday I will create a 3D model of the Kaman SH-2B Seasprite helo that the ship carried, but right now I do not have very good drawings and dimensions to work from.


The next step it to start creating the plans for the actual 1:96 scale model.



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The 3D model is about a gigabyte (for comparison, the 3D CAD file for my house is only about 20 megabytes). I have included details down to 3/16 inch (1:1 scale) - primarily fasteners such as screws and rivets. But there were a few places where I omitted some of the tiny details (screw threads and some very small rivets) in order to keep the file sizes smaller.


I put in all the details with the hope of someday generating walk around videos.


I have started generating 2D files. The forward superstructure file took several days to generate and the resulting file is 345 megabytes. After cleaning it up to remove unwanted lines and duplicate line segments it should be quite a bit smaller. But it is going to take a long time to generate all of the files.


Right now I am taking a break from CAD and I am building a 1:48 scale model of a Baltimore clipper revenue cutter.



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