07/31/2010 - 3" 50 Cal Lesson Plan

This is an outline of a talk I gave on 7/31 to other Docents (Tour Guides) and Student Interns about the 3" 50 Cal Gun. While the Mark 22 (shown above) was used on most Destroyer Escorts with 3" 50 Cal.; the USS Slater has Mark 26 mounts.

1. Basics
• 3" Diameter
• 50 Caliber: Gun Length = Caliber * Diameter (3*50=150")
• Range - 14,600 yards, 29,400 ft Ceiling
  
• Rate of Fire - 15 rounds per minute
  
• Dual Purpose - A/A, Surface
• Muzzle Velocity 2,700 fps
• Recoil Length - 11-1/2"
• # used: WWII Start - 690; WWII End - 14,002
• Chrome Plated Barrel, 4,300 rounds
  
2. Main Components
• Barrel - Gun
  
• Housing - Breech
  
• Slide - Recoil/Counter Recoil Mechanism
  
• Mount (vs. Turret), Stand
  
• Elevation / Train Power Drives
• Sight Setter - Sights
• Fuse Setter
• Ready Service Ammo Boxes
• Salvo Latch, Hand Operating Level
  
3. Operation - Gun Crew
• 11 Man Crew
• Mount Captain
• Pointer
  
• Trainer
  
• Sight Setter
  
• Loader (Plug man)
  
• Hot Shell Man
• Fuse Setter (2)
• Ammo Passers (2)
• Sight Checker
• Pointer, Trainer, Sight Setter Duties depended on Mount Mark
  
• Hand Served - Loaded by Hand
• Fired Local or Remote
• Using Trigger (Electric) or Foot Pedal
4. Operation - Fire Control - Basics
   
• Influence of Gravity
  
• Wind
• Time of Flight, relative to target speed/course
• Temperature
  
• Range
• Ship Speed and Direction
• Roll
• Rifling
• Vibration (Gun vs. Director Control)
  
• Parallelex (Deviation from Director)
  
• Roller Path Distortion
  
• Ship Distortion - Flex
  
• Gear Distortion - Play
  
• AA - Fuse Setting Lag to load
  
5. History - Gun Mount and Fire Control Changes
   
• Mark 20 - Manual
  
• Mark 22 - Director Input (not control)
  
• Mark 26 - Director Control
  
• Later Changes - Mark 27, Twin 3"-50
  
6. Maintenance
• Routine Maintenance - Grease, Oil, Paint
• Effects of Salt Water (31 vs 33)
  
• Chamber and Barrel
  
• After Firing, Cleaning (Soda Ash), Paint Smiley Faces
  
• Sight Alignment - Bore Gage, Tram, Bore Sight
  
7. Safety
• Hang Fire, Miss Fire
  
• Cook offs
  
• Power Drives - Crushing
  
• Firing Cutouts - Shooting into the ship (none detailed on 3")
  
• Ouches & Burns
  
8. Ammunition
• Projectile - Approx. 13 lbs
• Fixed ammunition, approx. 7 lbs case (Steel/Brass), 4 lb propellant
  
• AA - 30 Second Mechanical Time Fuse (Green)
  
• AA - VT - Variable Time Fuse (Green)
  
• AP - Armour Piecing (Black)
  
• HC - High Capacity, Min. Wall Thickness (Green)
  
• Illumination (Star Shell, Stars and Light Blue)
  
• Smoke / WP (not available in 3")
  
• Short Charge
  
9. Overall Effectiveness
• Compared to 5" 38 (55 lbs, 18K yards, enclosed mount)
  
• USS Reeves - SS Seakay Experience
  
• AA - Director Control
• VT 3 X effective over MTF AA
10. Who Made What
• Naval Gun Factory - Charleston WV
• Naval Gun Factory - Washington DC
• Miehle Printing Press, Blaw-Knox, Baldwin Locomotive
  
• Arma Corp, Brooklyn NY
  
11. References
    
• Gun Mount And Turret Catalog, Ordnance Pamphlet 1112, 1945
• 3-INCH MOUNT MARK 20, 21, 22, OP 811, 1943
  
• U.S. Explosive Ordnance, OP 1664, 1947
• US Navy Administrative History WWII, No. 75, Chapter on 3" Guns
• Navy Weapons, 3"/50 Description
  
• Fire Control Fundamentals, Navpers 91900, 1953
• USS Slater, 3" Gun
• Naval Ordnance and Gunnery V1, Navpers 10797-A
• Principals of Naval Ordnance and Gunnery, Navpers 10783-B
• DE Docent - 3" 50 Cal Posts
  

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During the training, I was asked about the rate of fire for the 3" twin Mounts (Marks 27-33). It appears that the rate of fire was approximately 50 rounds per minute. As shown in the photo, these guns were loaded from either side, and the loader was synchronized with the cycle of the gun firing. Because the 3" could fire a VT fuse, many of the 40mm mounts were replaced with this type of gun during the post-war era.

07/11/2010 - Ships Laundry

I was asked today about who/how laundry was done? In the 60s (aboard both my cans) each compartment had two laundry bags, one for whites and one for colored (basically dungarees). Everyone's clothing was stenciled. A few times a week the person cleaning the compartment (always a junior seaman) would take the bags to the ships laundry. Next day he would pick it up, and then throw the clean laundry on everyone's rack (their bunk) so they could fold and stow. This process always occurred after inspection.

I discussed this topic with one of our WWII volunteers and it was fairly similar. Instead of laundry bags they used a sheet, and they didn't sort the clothing into white/color piles. This process was probably done in the ship's laundry.

The USS Slater has a virtual tour of the ship, and they have fairly good description of the laundry room, which is on the 1st platform, starboard side, aft (right side, near the end).

The description notes that the ships laundry equipment was manufactured by two companies: the Hoffman Machinery Company, and the American Laundry Machine Company. There are interesting on-line references to each company. The American Laundry Machine Company is a defunct set of buildings in Rochester, NY. The Hoffman Machine Company was the centerpiece for a holding company in the 1950s.

07/18/2010 - Convoys, Armed Guard

This Sunday I gave two tours. One group was comprised of family members of WWII Destroyer Escort Weapons officer. It was a great tour. The DE Sailor was over 90, so the tour took time. We opened the flying bridge (which was the duty station for the Weapons Officer). It took a while for the to climb the steep ladder. It was a great accomplishment. I'm glad we had a special tour.

Prior to service on a Destroyer Escort, the vet told me that he served as an Armed Guard Officer. He noted that he sailed on convoys near Iceland. I was happy that I had an opportunity to serve as the guide for this visit. However, I really wished that they visited on Friday, when Bob Bull was on duty on the USS Slater. Bob was a WWII DE sailor who also served as an armed guard.

Here are a few links relative to Armed Guard Service in WWII:

• A very detailed history of the armed guard service is on-line: Administrative History of the Naval Armed Guard Afloat in WWII (OP-414). One chapter summarizes their mission: "....The Armed Guards had only one main mission -- to defend merchant ships and transports from enemy air, surface, and submarine attacks. Their primary duties, therefore, were watch standing and manning guns and maintenance of guns and defensive equipments. They had nothing to do with running the merchant ships although they greatly assisted at times in fighting fires, and in salvage operations, especially when the merchant seamen became panicky or abandoned ship. ...."

• The picture above details an attack on an arctic convoy to Russia in 1942 (PQ-18). A detailed listing of all convoys is available at Arnold Hague Database on Convoy Web. PQ Series convoys typically departed from Iceland. Here is the Arnold Hague entry for PQ-18.
  

• The period from 1939 to 1943 was a tough time for Merchant Ships, During this period 5,758 ships were lost from all causes. The combined tonnage was 22,161 (thousand), in modern terms these losses would equate to the loss of over a 1/2 million tractor trailer trucks (using a 40 ton base for a tractor trailer).

• Another blogger (Bud, from Ft. Wayne) has written a detailed story about the Armed Guard which is a good read.

• There is a detailed web site dedicated to the Armed Guard (Armed-Guard.com): "....The U.S. Navy Armed Guard was a service branch of the United States Navy that was responsible for defending U.S. and Allied merchant ships from attack by enemy aircraft, submarines and surface ships during World War II. The men of the Armed Guard served primarily as gunners, signal men and radio operators on cargo ships, tankers, troop ships and other merchant vessels. Disbanded following the end of the war, the Armed Guard is today little known or remembered by the general public, or even within the Navy. ...."

• Naval History Center has an interesting oral history account about an Armed Guard Sailor, Seaman Basil Izzi, "....an Armed Guard crew member on the Dutch merchant ship SS Zaandam which was torpedoed by German submarine U-174 off the coast of Brazil. He was rescued after 83 days adrift on a raft, 2 Nov 1942 - 24 Jan 1943. ..."
  
  

07/05/2010 (Monday) - More on 3"

There seemed to be plenty of guides on 4th, so I worked on Monday 5th instead. Seemed pretty slow, I gave one tour and went home early.

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It appears that everyone is stumped with the power button setting (fast/slow ) for the 3" Mark 31 Elevation Power Drive (Follow-up on my June Entry). Tim sent out e-mails to different experts throughout the historical fleet. During the inquiry we were sent this neat photo of a 3" gun being fired. The photo caught the 3" empty case being ejected. You can see the loader ready to ram another round, while the hot shell man (with his protective glove) tries to catch the hot empty. Since some of the sailors are in whites (probably trainees) and others are in dungarees (probably trainers) we think that the photo is from a training exercise perhaps on the USS Wyoming (BB-32). One of our volunteers, Master Chief Floyd (since retired) served on the Wyoming in 1943.

".... The extent of her operations can be seen from a random sampling of figures; in November, Wyoming trained 133 officers and 1,329 men in antiaircraft gunnery. During that month, she fired 3,033 5 in (130 mm) shells, 849 3 in (76 mm); 10,076 40 mm; 32,231 20 mm; 66,270 .30 in (7.62 mm); and 360 1.1 in (27 mm) ammunition. She claimed the distinction of firing off more ammunition that any other ship in the fleet, training an estimated 35,000 gunners on some seven different types of guns. ..."

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The Mark 31 power drive was the 1st attempt to link 3" 50 cal to director control. This upgrade resulted changed the Mark # to 26. This was not a major mark and it's very hard to find documentation about the upgrade. The best document to date is an Ordnance Bulletin 1-1946. The bulletin notes that the upgrades started after August 1945, after the USS Slater deployed to the Pacific. Our theory is that the upgrade may have occurred when the USS Slater was transferred to the Greek Navy. The bulletin does not mention the dual setting of the elevation power button. However, there is no doubt the USS Slater is equipped with Mark 26 Mounts.

Expect more on this issue in subsequent posts.