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The PT Boat Forum ª PT Boats of WWII ª  PT Boats - General

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 Author  Topic: Loading Torrpedos in Tubs.
Bob Butler

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Apr 22, 2013 - 10:01pm
I doing my model with the covers off the tubs. I'm using the Italeri Mk VIII's. On the tip of the torpedos there is a ring, does the ring. come off and a fuse screw in, Or is the ring part of the fuse. If so is there any up and down or lert or right. for the position of this ring after it's placed in the tub?


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PeterTareBuilder2

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Apr 22, 2013 - 10:45pm
Ring is replaced with a fuse. Fuse is a totally separate piece from the ring.

Cheers

"Give me a fast boat for we want to get out of harm's way too."

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  Jerry Gilmartin

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: Apr 23, 2013 - 2:20pm
Hi guys,
I think you have the entire concept wrong. The Ring is welded to the front. The Mark 8 torpedo does not have a "Fuse" like a aerial bomb would. It is properly called an "Exploder Assembly" and it is installed up inside of a void space on the bottom of the warhead about a foot back from the nose. From the outside of the torpedo the Exploder appears like an oval shaped plate attached to the underside of the warhead. The Exploder contains a small paddlewheel that is turned by the torpedoes forward motion through the water to arm the Detonator. (I think Jack Duncan calculated it was a couple of hundred yards). The paddlewheel cocks a hold back lever and a spring loaded hammer. When the torpedo hits up against something, a weighted ring (called a trigger ring or flop ring) moves and pushes up against a trigger plate. The trigger plate then pushes up on the mushroom cap. The mushroom cap has an internal trough that allows spring loaded "detent" balls to push out and release the spring loaded hammer. The hammer has two firing pins that penetrate two matching primer caps. The primer caps burst into flame and set off the dime sized Fulminate of Mercury Detonator, the detonator then sets off the Tetryl Booster Charge (about the same size as a can of Vienna Sausages) The Tetryl Booster charge then sets of the main TNT or Torpex Charge and the warhead explodes. Got all that?
By the way, I got all this information from the book "US Naval Ordinance" dated 1944, and also from the Mark 13 torpedo technical manual, The Exploder Mechanism, Mark 4 was developed in 1923 and was not subject to the same problems as the later Mark 6 Exploder used on submarine Mark 14 torpedoes.

I have a photograph of this Exploder Mechanism somewhere on Photobucket and will try to post it later.

The Ring on the front is usually welded to the outer casing of the warhead and is used for lifting either the entire torpedo after it is assembled, or just the warhead by itself. I dont think it can move to the right or to the left or up and down.

Jerry Gilmartin

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Bob Butler

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Apr 23, 2013 - 5:18pm
Thanks Jerry, when the torpedo is in the tube and your looking at it, would the ring be up and down , sideways or etc. I'm refering to the position of the torpedo in the tube. does it matter or can it be laying any which way. or is there a proper way of putting it in and would all the rings be in the same position.


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  Jerry Gilmartin

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: Apr 23, 2013 - 5:56pm
Hi Bob,
Ok yes, I am pretty positive the main axis of the lifting ring would be in the vertical plane. That way the bending stress is spread out better when it is being used to lift the torpedo.
Jerry

Jerry Gilmartin

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alross2

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of alross2   Send Email To alross2 Posted on: Apr 23, 2013 - 6:57pm
Quote:

Thanks Jerry, when the torpedo is in the tube and your looking at it, would the ring be up and down , sideways or etc. I'm refering to the position of the torpedo in the tube. does it matter or can it be laying any which way. or is there a proper way of putting it in and would all the rings be in the same position.





Yes, it definitely matters. There are guides inside both types of tubes (MK18, MK19). Go here and read chapter 6. http://www.ibiblio.org/hyperwar/USN/ref/PT-Manual/MTBM-2.html#C6

Al Ross


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  Jerry Gilmartin

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jerry Gilmartin   Send Email To Jerry Gilmartin Posted on: Apr 24, 2013 - 1:42pm
Hi Bob,
I found those photos on Photobucket. I will post them here. In them you can see the diagram for the exploder and the photos of loading an old Mk8 torpedo on board Ted Berlins PT167 in Rendova. In one you can see the ring that is welded to the nose of the torpedo warhead. It has a tagline tied to it to guide the torpedo as it is being lifted by the crane. You can see the orientation of the ring as well. Just as an aside, this is a Practice dummy warhead as indicated by the yellow color and the two round access plate covers on the top of the warhead. I hope these are helpful. Jerry

Exploder operating diagram


Explanation of operating diagram



Loading onto PT167



On a cart



Loading onto PT167 showing nose ring orientation




Loading onto PT167



View of old Mk8 being lifted at Rendova view of bottom side of warhead possibly can see exploder mech



PT fires practice torpedo off Rendova note orientation of nose ring
PTfirespracticetorpedonearrendovaJan44pt2.jpg" border="0">

Firing practice torpedo

PTfirespracticetorpedonearrendovaJan44pt1.jpg" border="0">

Locating the spent practice torpedo



Towing the torpedo by the nose ring back to Rendova



I hope this clarifys what I am talking about. Jerry

Jerry Gilmartin

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Bob Butler

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Apr 24, 2013 - 5:25pm
Good deal THANK YOU!, so much.


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Will Day

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Apr 24, 2013 - 8:48pm
Great sequence of photos, Jer.

Will

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David Waples

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of David Waples  Posted on: Apr 24, 2013 - 9:37pm
I have seen photos of Mk. VIII torpedoes without rings on the nose. I'll hunt around and see if I can find some. Any thoughts about that???
Dave

David Waples

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