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 Author  Topic: PT 109 Depth Charge Placement
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 10, 2018 - 9:08am
True story - some 35 or so years ago when I did the drawing of 109 that Dave shows above, that's how I arrived at the placement of the depth charge rack. With the tube cranked fully outboard, I estimated the minimum distance the torpedo would need to clear the rails on the rack. I figured the rails would be at or beyond the deck edge, as the charge would hit the deck otherwise. Thus, the placement of the rack.

Al


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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 10, 2018 - 9:08am
True story - some 35 or so years ago when I did the drawing of 109 that Dave shows above, that's how I arrived at the placement of the depth charge rack. With the tube cranked fully outboard, I estimated the minimum distance the torpedo would need to clear the rails on the rack. I figured the rails would be at or beyond the deck edge, as the charge would hit the deck otherwise. Thus, the placement of the rack.

Al


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Jeff D

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jeff D   Send Email To Jeff D Posted on: Apr 11, 2018 - 7:59am
Thanks for the input guys, I've been using it to go at it again. This time I'm simulating an old 35mm film camera which changes the view markedly. I didn't notice I had them set to a "flat" perspective which doesn't show the view a real camera would capture.

Thanks for the story Stearman, it sounds like a DC was put to good use at least once! Does anyone know of other occasions when they were used?

Dave reminded me of this one, the free rolling across the deck for several feet looks a bit sketchy to me. Dave also pointed out that they moved the cleat forward quite a bit:

jQ8Mw.jpg

That is a unique setup Dick! It looks like it is leveled. I can't tell if the tracks go all the way to the edge:

jQzBH.jpg

All this and as far as I know we don't really know if she still carried DC's at the time she went down. Somebody posted a book quote of the torpedo / DC incident once, does anyone remember the thread it was on?

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Drew Cook

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Drew Cook  Posted on: Apr 11, 2018 - 11:57am
Jeff,

I think I posted the detailed quote from Al Cluster about the 109 torpedo smacking the depth charge from the book "John F. Kennedy: War Hero" by Richard Tregaskis, an expanded edition of the Landmark book "John F. Kennedy and PT 109."

If I can't find the thread, I'll post it again.


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Dick

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Dick   Send Email To Dick Posted on: Apr 11, 2018 - 12:09pm
Jeff . . . .

I've never seen this image before great shot - I hope the sea is very calm when they let that looses and let it roll off the deck ! ! ! ! ! ! My goodness . . .

Dick

jZSKa.jpg

Reminds me of this rack setup:. But at least the rack runners seems to go to the deck edge, unlike above.

j4hc7.jpg




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Jeff D

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jeff D   Send Email To Jeff D Posted on: Apr 11, 2018 - 6:43pm
Thanks Drew, I appreciate that.

Now that's an interesting rack Dick, I wonder how they released it! A crewman standing by with a really sharp knife?

Here's the full photo Dick, PT 143: https://i.imgur.com/vB7SzWQ.jpg

And a (partial) view from forward, note the 4 forward torpedoes *cough*: https://i.imgur.com/MJ5StwT.jpg



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Dick

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Dick   Send Email To Dick Posted on: Apr 12, 2018 - 9:16am
Thanks Jeff . . .

Nice torpedoes!

Either a really sharp knife or really good and fast at untying knots.

Typical Launching Procedures:
1.) The Ready Position: stand in front of the DC bracing your knees against it to keep it from rolling.
2.) Launch Activation: Sever the launching rope or quickly untie the knots, all while securing the DC from rolling with your knees.
3.) Launch DC: When instructed (signaled) by the skipper, quickly step to the side without stumbling, preferably to the aft.
4.) Launch Success: If launch was successful, return to your quarters and change your underwear!
NOTE - Proper Attire: Heavy duty steel-toed boots with traction soles and thick rubber knee pads.

What is astounding to me is not only the imaginative launching system, but, as you see the rope is only keeping the DC from rolling down the rack, not securing the DC to the rack itself. In other words pray for calm seas, cause I can imagine what might happen as they plane the waves at high speed and hoping for no big wave slaps.

Dick . . .


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Drew Cook

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Drew Cook  Posted on: Apr 12, 2018 - 2:58pm
The quote from Al Cluster about the PT 109 torpedo-depth charge incident (Cluster was at the wheel and throttles of the 109) from Richard Tregaskis's "John F. Kennedy: War Hero" is as follows:

"I got to going quite fast to try to stay on top of the waves, but I miscalculated and finally plowed into one at high speed. The port forward torpedo came charging out of its tube (not all the way) with its turbine going full blast and building up pressure in the tube.

"Lenny Thom, Jack's exec, took toilet paper and stuffed it in the impeller mechanism of the warhead so that the torpedo would not arm itself if it went into the water.

"About this time, the pressures of the exhaust in the tube built up and launched the torpedo straight into the forward depth charge (fortunately unarmed), driving it right through the plywood deck, where it fell through the crew's living quarters and went through two empty bunks."

Tregaskis ends with: "The launched, but not armed, torpedo then slithered off the deck and into the water, churning away at full speed."


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Jeff D

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Jeff D   Send Email To Jeff D Posted on: Apr 12, 2018 - 5:19pm
Hah Dick, I doubt that made it to the doctrine book!

Thanks Drew, so this happened before JFK took command.

I was able to match the 109 images fairly well using a view that imitates a camera, as far as I can tell I was wrong about them being a mix of before and after the torpedo incident. I edited my post to avoid confusion. What I came up with is very close to what David figured out. Nice work David!

From what I can tell the cockpit shots were taken by a crewman standing on top of the day cabin.

It looks like they leveled out the racks going by the 1st image (mine is about parallel to the deck), makes sense so that they would roll off freely. As long as they were going slowly in a calm sea...:

jhBm4.jpg

They may not have needed to cut out the toe rail, the rail was less then 3/4 taller than the gap under the rack. Some 1 pads would have done the trick:

jhjN6.jpg

Edited to show clearance for the toe rail if a 2 inch pad was used under the rack. And to correct the bass ackward toe rail:

jh48S.jpg

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Drew Cook

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Drew Cook  Posted on: Apr 13, 2018 - 2:38pm
Jeff,

No -- JFK was in command of the 109 at the time of the torpedo/depth charge incident. I thought that much was clear. Cluster had been patrolling in PT 48 along with JFK's 109 in the open ocean west of the Russells.

Cluster's 48 had a patch staved in on his port bow by the rough seas, the boat started going down by the bow, Cluster radioed for help, JFK and the 109 ran over to a U.S. destroyer and got a pump which they brought it back to the 48, Cluster's crew couldn't get the pump to work, Cluster and JFK maneuvered over to a small island named Buraku just north of the Russells (Cluster backing the 48 all the way), Cluster radioed Tulagi for a repair boat to come out and fix the 48.

Cluster then boarded the 109 and, continuing to quote from Tregaskis's book:

"Cluster, riding in the cockpit with Kennedy, was full of questions about the 80-footers. His own boat, and all the previous boats he had commanded, had been the older, 77-foot type, and he was very curious. He finally asked Kennedy if he could try the wheel.

Being essentially a sea-cavalryman like most good PT men, Cluster couldn't resist the temptation to try out the maneuverability and speed of the 80-footer. He swung into several turns, and then, as he later related the incident..."

The rest is the quote from Tregaskis's book I posted previously.

A shorter, less detailed version of this incident is also contained in Donovan's "PT 109 - John F. Kennedy in World War II."


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