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» Forum Category: PT Boats of WWII
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» Forum Name: PT Boats - General
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» Topic: Torpedo tube ignitor mount
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Greetings all,
I'm mastering new torpedo tube ignitors for my 1/48 Elco which is going well. What I'm looking for are some photos of the actual mount. I have a drawing that I'm working from but I can't tell from photos if the drawing is correct. This will be for a 103 class boat.
Thanks everyone
Dave

David Waples

Posted By: David Waples | Posted on: Feb 13, 2012 - 5:00am
Total Posts: 1679 | Joined: Jan 2, 2007 - 9:55pm



[IMaGe]http://i73.photobucket.com/albums/i204/alross2/Turret-Rings-01.jpg[/IMAGE]



Posted By: alross2 | Posted on: Feb 13, 2012 - 1:40pm
Total Posts: 993 | Joined: Oct 30, 2006 - 8:19pm



Thanks Al and Jeff for helping me with this one. It's a good thing I have friends that can help me recover from rectal cranial inversion. :-) I completely forgot about the torpedo tube drawings you guys shared with me. I think I'm closing in on the answer. Here are a series of drawings and photos of these ignitors.

The drawing from the parts catalog tells the story... I think. Check me on this and tell me what you think. First I have no idea what the chain is for. Any thoughts about that? That said there is a tube that wraps around the firing pin and appears to exit out of the housing for the firing pin at a 45 degree angle towards the deck. This being the most forward point in the ignitor. I believe that is the wire seen in the 109 photo (attached) that goes through the deck and to the cockpit. But, here's where I get confused. The photos don't look like it goes through the cartridge case cover. It looks like it's connected near the chamber. The drawing from PT Boats Inc. indicate it going through the threaded area of the firing pin cover. Any thoughts about this?

The drawings did resolve my original question about the mounting. But the drawings did lead to more questions. Thanks for your help and thoughts on this.
Dave

PS. ignore the red circles... they're from a previous post.

[IMAGE]http://i108.photobucket.com/albums/n27/David_Waples/PT%20BOATS/Torpedotubeignitor.jpg[/IMAGE]
[IMAGE]http://i108.photobucket.com/albums/n27/David_Waples/PT%20BOATS/MkVIIignitor.jpg[/IMAGE]
[IMAGE]http://i108.photobucket.com/albums/n27/David_Waples/PT%20BOATS/SternPT-109.jpg[/IMAGE]
[IMAGE]http://i108.photobucket.com/albums/n27/David_Waples/PT%20BOATS/PTBoatSprayShield2.jpg[/IMAGE]


David Waples

Posted By: David Waples | Posted on: Feb 13, 2012 - 7:45pm
Total Posts: 1679 | Joined: Jan 2, 2007 - 9:55pm



I forgot to include a photo that Jeff sent me. Better look at the mounting bracket.


[IMAGE]http://i108.photobucket.com/albums/n27/David_Waples/PT%20BOATS/snapshot20080930104040-1.jpg[/IMAGE]

David Waples

Posted By: David Waples | Posted on: Feb 13, 2012 - 7:49pm
Total Posts: 1679 | Joined: Jan 2, 2007 - 9:55pm



I am pretty sure the chain was just to stop the removable breech cover from being dropped over the side when they were opened during reloading. Jerry

Jerry Gilmartin

Posted By: Jerry Gilmartin | Posted on: Feb 13, 2012 - 10:43pm
Total Posts: 1469 | Joined: Oct 8, 2006 - 11:16pm



Well... that makes a lot of sense Jerry! I'm going to include it on my model but at this point I'm curious if it has another function such as a safety. It would make a great story when somebody says "why did you put that there?" :-)

Anyway...

Looking at these two pictures the cable must connect to the firing pin section of the ignitor somehow. With that section removed there's no sign of the cable. But in the second photo of the 77' boat you can clearly see the cable. It looks like when it's locked into position that cable comes out the bottom from somewhere. I'm just wondering if it's in the tapered throat or in the firing pin cover. It's a little confusing from the drawings...

[IMAGE]http://i108.photobucket.com/albums/n27/David_Waples/PT%20BOATS/snapshot20080930104040.jpg[/IMAGE]

You can see the cable here. I noticed the handles are at a different angle than I normally see them with the firing pin section in the locked position.

[IMAGE]http://i108.photobucket.com/albums/n27/David_Waples/PT%20BOATS/PT-61CheifTorpedoman.jpg[/IMAGE]

I would sure love to find something definitive on where this cable attaches.
Thanks everyone
Dave

David Waples

Posted By: David Waples | Posted on: Feb 14, 2012 - 5:33am
Total Posts: 1679 | Joined: Jan 2, 2007 - 9:55pm



I'm looking at that first picture that Al provided and it appears that the cable is going into the bottom of the tapered part of the firing pin section. Hard to see from the Elco parts manual drawing.

Jerry, looking at the drawing again I think you're right. The chain is simply to keep from losing the firing pin section. There seems to be some sort of tool attached to the chain but I don't see that in any of the photos.

Dave

David Waples

Posted By: David Waples | Posted on: Feb 14, 2012 - 5:42am
Total Posts: 1679 | Joined: Jan 2, 2007 - 9:55pm



The best view of the cable entrance is found on the drawing Combustion_Chamber_Details_3_BUORD_318361_Mod0. It looks like it angles out to the back:
[image]http://www.pt103.com/images/ptpics/21inch_AW_Torpedo_Tube_MK18_Combustion_Chamber_Details_3_BUORD_318361_Mod0_Cable_Exit.jpg[/image]

This photo shows the cable that looks to me to be too long, possibly a replacement:
[image]http://www.pt103.com/images/ptpics/Photo_Scan_PT_Unknown_Stern_Torpedo_Funnels_2_Firing_Mechanism.jpg[/image]

The chisel-like tool attached to the chain is described as an extractor. I'm not sure of its function, maybe to get the spent charge out?




Posted By: Jeff D | Posted on: Feb 14, 2012 - 8:48am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am



TO DAVE WAPLES:
TWO QUICK OBSERVATIONS REGARDING YOUR FEB .14 / 8:33 AM POST:
-I'M WONDERING IF THE BACK-UP TO THE AEGIS MISSILE SYSTEM IS STILL A GUY WITH A WOODEN MALLET...AND
-IF "RECTAL CRANIAL INVERSION" ISN'T AN ACTUAL NAVAL ORDNANCE TERM, IT SHOULD BE...

ROSS FISHER


ross@dupagels.lib.il.us

Posted By: ROSS FISHER | Posted on: Feb 14, 2012 - 6:51pm
Total Posts: 82 | Joined: Jul 23, 2008 - 10:03am



Thanks Jeff,
I think that seals the deal. I love the hammer hanging next to the firing mechanism. I wonder if they had 4 of those on the boat. I looked at a photo of PT-117 on the starboard side and I can just make out the little fitting where the wire hooks up to the firing mechanism. Now to go back and remake my master.

Ross, I wouldn't be a bit surprised if there was a backup firing system called a hammer for launching an Aegis missile.

Thanks everyone for your help.
Dave

David Waples

Posted By: David Waples | Posted on: Feb 14, 2012 - 8:15pm
Total Posts: 1679 | Joined: Jan 2, 2007 - 9:55pm