New heavy cruisers of the Salem class

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Gene Slover	New heavy cruisers of the Salem class	Lead	[-]
Posts: 6461 ( 4-Jul-2008 20:40:31) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	20A4. Aloft gun directors New heavy cruisers of the Salem class have Gun Directors Mark 54, which differ from the Mark 34 in having more complete provisions for control of the main battery against aircraft. The accompanying rangefinder is the Mark 66. The Salem Class main battery fire control computers are Mark 1Able with cams cut for the 8"/55 rapid fire guns. These computers compute both surface and AA ballistics for the 8"/55 rapid fire guns. Thus no change is needed in the fire control system in firing at either surface or air targets.
Gene Slover		#1	[-]
Posts: 6462 ( 4-Jul-2008 20:43:52) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The New heavy cruisers of the Salem class have Gun Directors Mark 54 and are equiped with the Mark 13 radar. The Mark 13 radar is virtualy useless against an air target so the Mark 54 directors are equiped with the newer and larger Mark 66 Rangefinder for use against air targets. This is why the rangefinder is so large and looks a little bugeyed:-) Hmmmmmmmmm
Gene Slover		#2	[-]
Posts: 6465 ( 5-Jul-2008 00:25:41) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	When it is desired or necessary to use radar against aircraft the Main Battery Mark 1A computers that have ballistic cams for the 8"/55's are switched so that they get range, bearing and elevation info from any one of the 4 Mark 37 directors. All of the Mark 37 directors are equiped with the Mark 25 Fire Control tracking radar. In this mode the 8"/55's are accurately directed against aircraft with radar and the gun orders are accurately computed.
Throd		#3	[-]
Posts: 584 ( 5-Jul-2008 02:49:09) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Thanks for info on RFs. The USN seem really keen to use the 8" in the AA mode to fit such large ones. I would imagine that they can only look at aircraft a long way off as they will be slow tracking.
Gene Slover		#4	[-]
Posts: 6466 ( 5-Jul-2008 06:16:28) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	(((Thanks for info on RFs. The USN seem really keen to use the 8" in the AA mode to fit such large ones. I would imagine that they can only look at aircraft a long way off as they will be slow tracking.))) Rangefinders were around long before radar. No the rangefinder is fast tracking near or far. When radar came around nobody trusted it. The rangefinders were always used to check the radar range to see if it was correct. Not the other way around. When I got out in 58 the rangefinder was still used to check the radar. Rangefinders do a lot of things radar cannot cdo such as track a tank with a mountain behind. Its fun to hit a tank with a 5" and watch it swell up and then explode and parts go flying everywhere. When radar first came out it had a lot of breakdowns. The rangefinder does not break down. By manning the rangefinder you are always training someone to operate it.
Gene Slover		#5	[-]
Posts: 6467 ( 5-Jul-2008 06:44:55) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The Mark 13 radar was very good for surface targets but not much use for anything else. The Mk 13 was not a tracking radar you had to constantly manualy move the range line to keep it on target. Much praise has been heaped upon the Mk 13 because of the "B" scope which we used to spot long range fall of shot. The Mark 25 radar which the Mk 37 system mounted was a much better radar but had not been around very long at this time. So it had not proven itself yet. The Mk 25 was a tracking radar which means it could track either a surface or air target in full auto out to its max range of 50,000 yds. In the Mk 37 director the trainer had a "B" scope with which he could see a display of the width of the radar beam in bearing. In the Mk 37 director the pointer had a "B" scope with which he could see a display of the height of the radar beam in elevation. The Mk 25 radar operator in the back of the Mk 37 director controled the size of the display on the "B" scopes of the pointer and trainer as well as the range scope he was looing at. When searching for a target the range operator sets the diapole antenna, that thing that sticks out of the center of the radar dish, to spiral condition which means that it makes the radar beam much bigger so that you can find the target easier. The radar operator also expands the length of the radar range scope he is looking at and the pointer and trainers "B" scope so that they all 3 see the full 50,000 yd range of the radar on all scopes. As the pointer and trainer move the director in train and elevation a target is spotted at about the range and bearing they have been told the target should be located. At this time the radar operator moves the range gate, which is a notch on his radar range line to near the target and then he expands the display so that all three scopes are showing only about 2500 yds of range. Then the radar operator should be able to gate the target in the range notch and the pointer and trainer should be able to center the target in their "B" scopes. At this time the radar operator can expand the scope to see only about 500 yds of range. Now the radar operator can switch the diapole antenna from spiral to conical and the radar can now lock on to the target. The radar cannot lock on it spiral it can only lock on in conical which is a much smaller pattern of radar and much more precise. Once the Mk 25 locks on then train, elevation and range are tracked automatically and the pointer, trainer and radar operator just sit there and watch the radar control the MK 37 director by keeping the director on target in elevation, bearing and range all automatically. Al of the quanities are automatically fed to the Mk 1A computer in plot. Now ain't that a Hoot:-)
Gene Slover		#6	[-]
Posts: 6468 ( 5-Jul-2008 06:49:53) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Most of the USN rangefinders were 24 power, which means even at long range you had a ring side seat to the target. The "B" scopes of the Mk 25 radar were every bit as good at spotting the fall of shot as the "B" scope of the MK 13 radar.
jlyons97	"really keen"	#7	[-]
Posts: 1574 ( 8-Jul-2008 18:51:05) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Throd wrote: Thanks for info on RFs. The USN seem really keen to use the 8" in the AA mode to fit such large ones. I would imagine that they can only look at aircraft a long way off as they will be slow tracking. Two reasons for the 'keeness:' 1. Savannah's experience off Anzio with cruise missles whose launch platform was outside gun range. 2. The radar picket DDs north off Okinawa, which came under sustained air attack not experienced before. So, need to 'get' the launch platforms before weapons release, and break up large (very large in the case of the Kamikaze attacks) formations as far out as possible. This was the begining of the 'defense in depth' concept of fleet AAW. Both the Salems and the Worchesters had this issue in mind (have to check the dates on the design phase). The issues still reverberate with AEGIS and NTDS. Plus airborne AEW. Plus the '50s SAM programs. That's why the USN fielded AEW ADs on carriers and PB-1Ws ashore before the start of the Korean War. Probably the 8" RF on the Salems remain the largest guns ever fielded anywhere capable of firing AA-fuzed ammunition in conjunction with a GFCS that was AA-capable.
Gene Slover		#8	[-]
Posts: 6489 ( 8-Jul-2008 19:53:59) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The 8"/55's also fired VT fused rounds and probaly more than of mechanically timed fuze.
Gene Slover		#9	[-]
Posts: 6490 ( 8-Jul-2008 19:58:37) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	One of the things I don't understand was the Des Moines and the Salem. All of these ships used the MK 13 for main battery and the MK 22 for the secondary battery. By the time the Salem was built the MK 25 tracking radar was available and it was far superior to the MK 13 in every respect and was much better at long range spotting.
Gene Slover		#10	[-]
Posts: 6491 ( 8-Jul-2008 20:19:17) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	It was a beautiful thing to watch or operate a MK 25 Radar with a MK 1A computer. Once you locked on to the Target everything was automatic. No matter what the target did or the firing ship did the director had the target in its cross hairs. At the MK 1Able all you had to do was stand and watch. The MK 1A did everything all by itself with no help from you. The MK 25 radar was un-jamable by anything at that time. When a number of other ships had MK 25's once in a while you might see a blip or ghost appear on your radar screen. The frequency of the adjustable magnetron was from 86,000 megacycles to 96,000 megacycles. About 1 1/4" long wave length. You could change the frequency of the magnetron with a slew switch and drive the magnetron to another frequency in an instant, at which time the blip or ghost would disappear. You could while tracking a target slew the magnetron from 86,000 megacycles to 96,000 megacycles constantly back and forth and never lose the target. The pulse repetiton rate could also be varied with a slew switch for about 750 to around 1350 per second. So the system was extraordinary.
jlyons97	far superior to the MK 13	#11	[-]
Posts: 1575 ( 8-Jul-2008 21:37:39) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Gene Slover wrote: One of the things I don't understand was the Des Moines and the Salem. All of these ships used the MK 13 for main battery and the MK 22 for the secondary battery. By the time the Salem was built the MK 25 tracking radar was available and it was far superior to the MK 13 in every respect and was much better at long range spotting. The Mk 13 was retained on the reactivated BBs of the 80s as well. By that time the Mk 25's successor (Mk 53) was available as well. Some peculiar advantage of the Mk 13?
Gene Slover		#12	[-]
Posts: 6493 ( 9-Jul-2008 01:09:42) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The MK 13 had some distortion in both range and bearing that you had to be aware of and pay attention to. This was caused mostly because of the wide width of the beam in bearing, some 5 3/4 degrees either side of center of the line of sight. This caused the presentation to bend in bearing slightly. The pulse width was 100 yds long and from a flat target that was about the range error of the MK 13. If the target was say a BB then because part of the pulse hit the sides of the ship and parts hit the stack then the range error was 100 yds plus the distance from the side of the ship to the stacks. Land mass did not do the MK 13 a favor and would give you a lot of problems with interference. You also could not lock onto a peak or other definate point on the land mass. The MK 25 was Automatic Tracking and the MK 13 was manual tracking. The Mk 25 pulse width was 60 yds and because the pip or target was a sharper image you could lock on and track automaticly the leading edge of the pip or target. The Beam was much smaller and land mass did not bother you as much because of less interference. You could lock onto and track points of land which was very important in accurate location of the ship relative to that point of land. Then you could reset the DRT so that it made an accurate track of the ship while you were doing shore bombardment. Then later you could come back at night and locate the ship from that same point and hit the same target weeks later without the aid of a spotter. Pretty slick. The smaller beam, you could have 3 types of sweep, allowed much more accurate shell spotting with the "B" scope. So the MK 25 was far and above the MK 13.
jlyons97	Naval Historical Center	#13	[-]
Posts: 1576 ( 9-Jul-2008 03:22:51) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Gene Slover wrote: The 8"/55's also fired VT fused rounds and probaly more than of mechanically timed fuze. http://www.history.navy.mil/faqs/faq96-1.htm This source (1950) gives probably as good an account of the development and more importantly, the problems with VT fuzes as is available. Interestingly, there is no mention of 8" RF fuzes, although there is such mention of those for 3"50, 5"38, 5"54 and 6"47 projectiles. It seems counterintuitive there would not have been such. Is there any other evidence out there that says so?
jlyons97	Mk 25	#14	[-]
Posts: 1577 ( 9-Jul-2008 03:24:29) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Ok, then. Why was the Mk 13 retained on the reactivated BBs?
Gene Slover		#15	[-]
Posts: 6494 ( 9-Jul-2008 04:15:27) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	The army was provided with 8" VT fuze at the Battle of the Bulge.
Gene Slover		#16	[-]
Posts: 6495 ( 9-Jul-2008 04:26:07) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	If you are really interested in the VT fuze. The VT fuze development effort in the 1940's is very nicely documented in "The Deadly Fuze, Secret Weapon of WW II" by Ralph B. Baldwin; 1980 Presidio Press. This book has 331 pages in it. I have a copy of this book. It is very good. Gene Slover Also article "Factors affecting the development of the radio proximity fuse 1940-1944" in IEE Proc.-Sci. Meas. Technol., Vol. 143, No. 1, Jan 96; by R.W.Burns (IEE Proceedings online no. 19960024) There is a video entitled The Deadly Fuze that is available through a couple of television stations in Michigan. Copies of the video may be obtained by contacting: WGVU-TV 35 and WGVK-TV 52 301 W. Fulton Grand Rapids, MI 49504 Tel: (800) 442-2771 I have this video and it is very good. In the video there are a number of the people worked with Dr. "T" on the project. Gene Slover
Gene Slover		#17	[-]
Posts: 6496 ( 9-Jul-2008 04:27:37) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	(((Ok, then. Why was the Mk 13 retained on the reactivated BBs?))) I don't have a clue. The MK 3, 8, and 13 were all good for the day and are given much praise especially as there was nothing better at the time. Not too many people operated the MK 13 and then the MK 25 or any of the later radars and learned of the improvements that had been made. Automatic tracking radar was unheard of during the war. I doubt that today you would find many that did. I liked them all and in the 50's I provided tech assistance to a couple of BB's Mk 13 radar. Last Edited By: Gene Slover 9-Jul-2008 04:34:58. Edited 1 times.
jlyons97	8" fuzes	#18	[-]
Posts: 1578 ( 9-Jul-2008 05:41:13) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Gene Slover wrote: The army was provided with 8" VT fuze at the Battle of the Bulge. Yep. Now back to the original question - 8" RF fuzes for the CA big guns.
Gene Slover		#19	[-]
Posts: 6497 ( 9-Jul-2008 05:48:32) Reply Quote More My Recent Posts Message Me Connection Blocking Invite Ignore User's Posts	Why don't you spend some time researching that.

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New heavy cruisers of the Salem class

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