What is it? Gun Director

What is it? Gun Director

Joined: October 10th, 2005, 8:42 pm

July 14th, 2008, 1:27 am #1

Stop by and see the aft Gun Fire Control Director tub. Larry and some friends have been working long hours on this project.
Some may remember last year that it was a real eye sore with the paint peeling off of it and it was right on the tour route. Larry could stand it no more and grabbed for a needle gun. Paint chips flew everywhere. He still has some work to do on it but it sure looks a lot better now.

What exactly is a gun director anyway? No, he doesn't lead a gun band.

The LST is currently equipped with two anti-aircraft 40mm batteries.
The forward battery consists of one twin 40mm cannon and two single 40mm cannons.
Two 20mm cannons add to the complement.
The aft battery has the same.

We will concentrate our discussion to the 40mm cannons. The 20mm cannons are controlled by the gunner firing them and have no automatic control.

Pick a buddy and pretend you are sitting on one of the single 40mm cannons. You can be the pointer and your buddy can be the trainer. You are at General Quarters Battle Stations. The lookout calls out "contact bearing 030 relative position angle 22 degrees inbound". The weapons officer acknowledges and assigns the target to your gun mount. Your gun captain scans the horizon for a moment and calls out "target in sight". He then calls out "Mount 42 target inbound 030 relative, position angle 22".
He may also point to the target to help the gun crew locate it. Meanwhile you, the pointer, crank the gun barrel up to 22 degrees. Your buddy, the trainer, is busy cranking the gun mount around to 030 degrees. When you see the airplane you yell "contact" your buddy does the same. When the gun captain yells commence firing, you, the pointer, use a foot switch to start firing the cannon. You only fire when the target is in your sights. A yoke control is also available to aim the mount but that is for another discussion.

Have you ever been skeet or clay pigeon shooting? You know that if the clay pigeon is moving pretty fast and you shoot right at it you will miss. By the time your gunshot reaches the proper distance, the clay pigeon has traveled out of the way. You have to learn to lead the target so that the buckshot and the target arrive at the same location at the same time.

The gun mount has a sighting ring on each position to aid you in leading the target. You take care of the vertical lead and your buddy takes care of the horizontal lead angle. With enough practice you learn to get pretty accurate.

With the production of faster and faster aircraft, this manual system was not as accurate. A gyroscopic gun sight called the Mk 14 was used to generate the proper lead angle and accuracy was improved greatly. You can see them on our 40mm gun mounts at the pointer's position. Incidentally they could be mounted on a 20mm gun also)

With each gun mount tracking its own targets it was hard to keep track of what was going on around you. Also, most gun mounts had limited visibility due to ship's structures being in the way. The next step was the inclusion of a MK 51 Gun Fire Control System (Mk 51 GFCS) A tower or deck elevated above the guns would give the gunnery officer a much better view of the surrounding area. It is kind of what the forward observer did on shore, climb to a high elevation for a better view.

By putting one of the gyroscopic gun sights up in this observation platform and electronically connecting it to the gun mount, the gun could be controlled much more accurately. The guns could also be fired from this position. Additionally, more than one gun could be controlled by a single sight to increase the firepower at the target. The gun director operator had only to follow the target and the correct lead angles would be automatically fed to the guns. (editor's note: The gun director had to learn to move the gun director smoothly and not make abrupt movements. The gun mount follows the gun director's movements exactly and a sudden jerk or movement could cause a member of the gun crew to slip or fall. It is rumored a few fist fights started this way)

Commonly called the gun fire control tub or gun director, this gunfire control system was manned by two.
The gun fire control officer and the gun director operator. With switches (you can see on the side of the director tub) the weapons officer could switch the gun director to the appropriate mount(s).

The gun director could control the following combinations:
The 40mm twin mount
The starboard 40mm mount
The port 40mm mount
The 40mm twin mount and the 40mm starboard mount
The 40mm twin mount ant the 40mm port mount
It could not control all three at the same time.

Due to lack of documentation I can not say if the forward director could control an aft gun and vice versa, but it would be highly unlikely.

Of course the individual gun captains could switch from auto to manual control at will.

Under each gun mount you see what looks like an old fashioned car horn (the kind that went ooogaaa ooogaaa. This is a Cease Fire alarm and is quite loud. You can see one at the top aft end of the director tub also.

Of course it is rumored that if someone ask Larry what the large round tub was for he might tell them it was used to cook soup for the crew and do laundry in on Sundays.

Tor the technical geeks you can see more information on

http://www.navweaps.com/index_tech/tech-049.htm

http://www.mts.net/~jkrocker/gunsight/index.html






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Joined: January 17th, 2006, 3:42 am

July 14th, 2008, 1:51 am #2

With all due respect, the following crew members should receive equal credit.

Pete Crasher on the needle gun
Marvin Oeth on the paint squad
Bob Pointer on the primer squad
Ed Duncan on the ladder removal and re-installation squad
Larry Hahn on Primer and finish paint squad.

Working together, the "tub" looks like new.

If I missed anyone, please let me know as it is lack of memory on my part, this has been going on for a long time.

Thanks to all.

Larry
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Joined: October 10th, 2005, 8:42 pm

July 14th, 2008, 11:44 am #3

Thanks Larry,
I knew there were others but my memory is shorter than the re-enlistment line.


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Joined: March 16th, 2006, 2:08 am

July 14th, 2008, 6:14 pm #4

With all due respect, the following crew members should receive equal credit.

Pete Crasher on the needle gun
Marvin Oeth on the paint squad
Bob Pointer on the primer squad
Ed Duncan on the ladder removal and re-installation squad
Larry Hahn on Primer and finish paint squad.

Working together, the "tub" looks like new.

If I missed anyone, please let me know as it is lack of memory on my part, this has been going on for a long time.

Thanks to all.

Larry
Hey Larry, after all I did take a picture of you guys working and sweating......and I had to come out of the air conditioning to do it........
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Joined: March 11th, 2008, 1:34 am

July 14th, 2008, 9:11 pm #5

I think this is something the Greek navy
put on ship we didn't have any on two
LST's I was on in WW2 I was a Gunner mate
If anyone want's to know what we had I
will be on the river trip and be glad
to show you
Ellis
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Joined: October 21st, 2003, 12:31 am

July 14th, 2008, 11:04 pm #6

Stop by and see the aft Gun Fire Control Director tub. Larry and some friends have been working long hours on this project.
Some may remember last year that it was a real eye sore with the paint peeling off of it and it was right on the tour route. Larry could stand it no more and grabbed for a needle gun. Paint chips flew everywhere. He still has some work to do on it but it sure looks a lot better now.

What exactly is a gun director anyway? No, he doesn't lead a gun band.

The LST is currently equipped with two anti-aircraft 40mm batteries.
The forward battery consists of one twin 40mm cannon and two single 40mm cannons.
Two 20mm cannons add to the complement.
The aft battery has the same.

We will concentrate our discussion to the 40mm cannons. The 20mm cannons are controlled by the gunner firing them and have no automatic control.

Pick a buddy and pretend you are sitting on one of the single 40mm cannons. You can be the pointer and your buddy can be the trainer. You are at General Quarters Battle Stations. The lookout calls out "contact bearing 030 relative position angle 22 degrees inbound". The weapons officer acknowledges and assigns the target to your gun mount. Your gun captain scans the horizon for a moment and calls out "target in sight". He then calls out "Mount 42 target inbound 030 relative, position angle 22".
He may also point to the target to help the gun crew locate it. Meanwhile you, the pointer, crank the gun barrel up to 22 degrees. Your buddy, the trainer, is busy cranking the gun mount around to 030 degrees. When you see the airplane you yell "contact" your buddy does the same. When the gun captain yells commence firing, you, the pointer, use a foot switch to start firing the cannon. You only fire when the target is in your sights. A yoke control is also available to aim the mount but that is for another discussion.

Have you ever been skeet or clay pigeon shooting? You know that if the clay pigeon is moving pretty fast and you shoot right at it you will miss. By the time your gunshot reaches the proper distance, the clay pigeon has traveled out of the way. You have to learn to lead the target so that the buckshot and the target arrive at the same location at the same time.

The gun mount has a sighting ring on each position to aid you in leading the target. You take care of the vertical lead and your buddy takes care of the horizontal lead angle. With enough practice you learn to get pretty accurate.

With the production of faster and faster aircraft, this manual system was not as accurate. A gyroscopic gun sight called the Mk 14 was used to generate the proper lead angle and accuracy was improved greatly. You can see them on our 40mm gun mounts at the pointer's position. Incidentally they could be mounted on a 20mm gun also)

With each gun mount tracking its own targets it was hard to keep track of what was going on around you. Also, most gun mounts had limited visibility due to ship's structures being in the way. The next step was the inclusion of a MK 51 Gun Fire Control System (Mk 51 GFCS) A tower or deck elevated above the guns would give the gunnery officer a much better view of the surrounding area. It is kind of what the forward observer did on shore, climb to a high elevation for a better view.

By putting one of the gyroscopic gun sights up in this observation platform and electronically connecting it to the gun mount, the gun could be controlled much more accurately. The guns could also be fired from this position. Additionally, more than one gun could be controlled by a single sight to increase the firepower at the target. The gun director operator had only to follow the target and the correct lead angles would be automatically fed to the guns. (editor's note: The gun director had to learn to move the gun director smoothly and not make abrupt movements. The gun mount follows the gun director's movements exactly and a sudden jerk or movement could cause a member of the gun crew to slip or fall. It is rumored a few fist fights started this way)

Commonly called the gun fire control tub or gun director, this gunfire control system was manned by two.
The gun fire control officer and the gun director operator. With switches (you can see on the side of the director tub) the weapons officer could switch the gun director to the appropriate mount(s).

The gun director could control the following combinations:
The 40mm twin mount
The starboard 40mm mount
The port 40mm mount
The 40mm twin mount and the 40mm starboard mount
The 40mm twin mount ant the 40mm port mount
It could not control all three at the same time.

Due to lack of documentation I can not say if the forward director could control an aft gun and vice versa, but it would be highly unlikely.

Of course the individual gun captains could switch from auto to manual control at will.

Under each gun mount you see what looks like an old fashioned car horn (the kind that went ooogaaa ooogaaa. This is a Cease Fire alarm and is quite loud. You can see one at the top aft end of the director tub also.

Of course it is rumored that if someone ask Larry what the large round tub was for he might tell them it was used to cook soup for the crew and do laundry in on Sundays.

Tor the technical geeks you can see more information on

http://www.navweaps.com/index_tech/tech-049.htm

http://www.mts.net/~jkrocker/gunsight/index.html





I was on the 1132 which became ARL 31 and we had gun control tubs and Quad 40's both fore and aft. Also a number of 20's.
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Joined: August 24th, 2003, 10:08 pm

July 15th, 2008, 12:43 am #7

innovative CO's who put those SeaBees to work making modifications that they wanted... Dad's CO did.. they had them install a sprinkler system on the tank deck. Did any of your T's have one and was it installed at the shipyard, or like the 125, was it a modification made later by 'volunteers'?

They also had them mount some additional 20 and 40 mm guns that were 'located' when they were at Noumea, New Caledonia.
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Joined: January 17th, 2006, 3:42 am

July 15th, 2008, 12:51 am #8

I think this is something the Greek navy
put on ship we didn't have any on two
LST's I was on in WW2 I was a Gunner mate
If anyone want's to know what we had I
will be on the river trip and be glad
to show you
Ellis
The Greeks didn't put the directors on the 325. If you will go back through the files that show the 325 in trials as L144, the gun directors were already on the ship.
BTW, I also noticed the four LCVP's in the same picture and this picture was taken before the ship was transferred to the Greeks. This means WE put them on the 325. (United States)

If you can't find this picture, let me know and I will send it to you.

LH
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Joined: January 17th, 2006, 3:42 am

July 15th, 2008, 12:53 am #9

innovative CO's who put those SeaBees to work making modifications that they wanted... Dad's CO did.. they had them install a sprinkler system on the tank deck. Did any of your T's have one and was it installed at the shipyard, or like the 125, was it a modification made later by 'volunteers'?

They also had them mount some additional 20 and 40 mm guns that were 'located' when they were at Noumea, New Caledonia.
The LST 325 has sprinklers over the tank deck. I have no idea if they were put on when the ship was built or later.

Larry
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Joined: January 17th, 2006, 3:42 am

July 15th, 2008, 12:56 am #10

Hey Larry, after all I did take a picture of you guys working and sweating......and I had to come out of the air conditioning to do it........
Sorry Don, I forgot the most important person on the project. Please forgive me.

Ok, folks, Don came out of the cool office and took the pictures.

Don Hardisty, photo squad

Larry
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