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» Forum Category: PT Boats of WWII
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» Forum Name: PT Boats - General
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» Topic: Question for Al Ross
http://www.ptboatforum.com/cgi-bin/MB2/netboardr.cgi?cid=101&fid=102&tid=2487



AL,

Your book Allied Coastal Forces has a nice detailed drawing and detail of the 21" PT Boat Torpedo Tube but does not explain how it was retained on the deck. Was it held down by some fixing ie. bolts or other form or like the Battleships turrets were they held down by there own weight?

The forward travers gear "nut" and the "T slot" appear to be all that hold the tube down as the rear pivot does not appear to have a holding band attached.

D.buck

Posted By: David Buck | Posted on: Feb 9, 2012 - 11:27pm
Total Posts: 332 | Joined: May 4, 2008 - 2:59am



I'm not going to be around my references until Sunday, but will look then. Jeff did some work with the factory drawings of the MK18 and may have the answer for you sooner.

Al



Posted By: alross2 | Posted on: Feb 10, 2012 - 4:20am
Total Posts: 993 | Joined: Oct 30, 2006 - 8:19pm



Check this thread out David. There are some photos and a link to the drawings Al supplied me with:
[url]http://www.ptboats.org/cgi-local/sitenetbbs/netboardr.cgi?fid=102&cid=101&tid=2415&pg=4&sc=20&x=0[/url]




Posted By: Jeff D | Posted on: Feb 10, 2012 - 6:35am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am



Thanks guys the photo does answer part of the question, it showes that there is no form of attachment other than the "Z' plates and traverse "Nut" at the frount of the tube.

As has been mentioned the turntable at the rear of the tube took the major amount of force at time of fireing I was wondering if the turntable is held down with some form of fixing to stop it lifting up?


Interesting to note that the damage to the " Z " appeares to be to the inboard section of the plates, wondering if the ride of the Boat up and down could be part of the cause of this as the outboard section appears fine.


D.buck

Posted By: David Buck | Posted on: Feb 11, 2012 - 2:04am
Total Posts: 332 | Joined: May 4, 2008 - 2:59am



I'm not sure if / how the turntable was secured David, but I doubt weight alone held the tube down. Here's more of the image showing the turntable damage. According to Jack Duncan who served aboard the 103 the damage might have been done stateside at the dock. Here's a quote from him:

[green]No, but this must be the story that the old guys told me about -- perhaps. I'm guessing. An officer reportedly an actor named Montgomery (Robert??) crashed into the dock at or near the Elco factory in Bayonne not long after the boat was built in June 1942.[/green]

[image]http://www.pt103.com/images/ptpics/Photo_Scan_PT_103_Port_Bridge_Torpedo_Turntable.jpg[/image]




Posted By: Jeff D | Posted on: Feb 11, 2012 - 7:34am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am



Here is the complete image:

[image]http://www.pt103.com/images/ptpics/Photo_Scan_PT_103_Port_Bridge_Torpedo.jpg[/image]




Posted By: Jeff D | Posted on: Feb 11, 2012 - 8:22am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am



Jeff;
This photo is probably the reason why "he" was later made Exec on PT 107. He also accompanied Jack Searles part of the way to Panama on PT 60,(I believe he got off the boat in either Charleston or Miami, because fans would flock to the pier, once word got out he was aboard) when Jack brought PT 60, Tom Warfield took PT 61, and Charlie Mills took PT 59 down to Panama in Spring 1942.
Take care,
TED



Posted By: TED WALTHER | Posted on: Feb 11, 2012 - 11:12am
Total Posts: 3058 | Joined: Oct 16, 2006 - 7:42am



Robert Montgomery may have started out badly on PTs (as I recall, so did Dick Keresey, who also dinged up the 103 as her took her away from the Elco dock) -- but it sure looks like he knows what he's doing at the helm of that 80' Elco in "They Were Expendable."

Watch the way he works the wheel, as he brings the boat in a couple of times in the film...

"All boats from Brick...scatter-plan Baker...Execute, execute!"



Posted By: Drew Cook | Posted on: Feb 11, 2012 - 2:34pm
Total Posts: 1306 | Joined: Oct 19, 2006 - 10:44am



Yes, I seem to remember interviews with some of the crew members during the TWE filming. They seemed to feel that RM's boat handling passed muster. I think after viewing photos of some of the dinged-up boats Out In The Area that minor collisions with stationary objects was not an uncommon occurance.

Will

Posted By: Will Day | Posted on: Feb 11, 2012 - 4:46pm
Total Posts: 1955 | Joined: Oct 8, 2006 - 4:19pm



Will;
Yes it was VERY common.
take care,
TED



Posted By: TED WALTHER | Posted on: Feb 11, 2012 - 6:45pm
Total Posts: 3058 | Joined: Oct 16, 2006 - 7:42am



Thanks Jeff and Ted

The photo in this instanct does show that there is no form of fixing of the tube to the deck, I say that because in looking at the damage to the lower support of the mount some of the turntable is damaged were as if there had been a more permernant attachment of the tube to the turntable support the lower turntable plate would have been torn away from the deck strengthener and there is clearly no damage to the plate bolted to the deck.

This is what I asked Al to clarify as his drawing does not show any form of connection and this photo tends to bear out the fact that the only thing that held the tubes down onto the turntable was the weight of the tube and a faily close fit of the turntable ,such as most larger turrets are held down only by there weight.

Something to think about, as the Bismark sank she turned turtle and all her turrets fell off and then she righted herself and landed upright on the bottom many fathoms below.

Something to think about !

Al You may find somethine differant if you do I would greatly appeciate your view.

D.buck

Posted By: David Buck | Posted on: Feb 12, 2012 - 4:37am
Total Posts: 332 | Joined: May 4, 2008 - 2:59am



Hopefully Al can help. No man on earth knows PT boats better than he. But in the meantime, I'll stick with thinking they were held down. The "turntable base" drawing seems to show 4 slots in the side view and in detail AA, and the damaged base photo seems to show them also. The "turntable and details" drawing looks like it shows corresponding retaining pin bosses on the moving part of the turntable. I may be wrong but the more I'm looking at the drawings the more I'd bet money on it.




Posted By: Jeff D | Posted on: Feb 12, 2012 - 6:43am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am



After looking at the photos and drawings, I think I agree with Jeff - there had to have been a mechanical holddown of some sort. Here's my thoughts (remembering I have no engineering background...)

[IMaGe]http://i73.photobucket.com/albums/i204/alross2/turntable.jpg[/IMaGe]

There are four slots in the turntable base vertical tube. The saddle tube fits down over the turntable base tube and has four bosses on it. Each boss has a large diameter hole and a small diameter hole. I didn't see any text about threads on the drawing, but would guess that a plate with a large diameter pin welded to it would be attached to the boss with a bolt through the smaller hole after the saddle tube was placed over the turntable tube. The pin would be long enough to pass through the slot, acting as a stop for vertical movement. The interior gussets in way of the slot may have had a corresponding slot milled in their edge where they met the tube, but that wouldn't be much of a problem. The elongated slots would allow the tube to pivot (only 12 degrees needed) and would act as a mechanical stop (pin hitting the end of the slot) to prevent an overzealous torpedoman from cranking the tube too far.

Plausible??

Al







Posted By: alross2 | Posted on: Feb 12, 2012 - 1:58pm
Total Posts: 993 | Joined: Oct 30, 2006 - 8:19pm



Hi Al,

Quite plausible I think as in the closeup shot three of the four damaged areas appear to have what would have been the bottom of the slot visible with the top section torn away.

(when there is damage to a metal item you generaly do not end up with nice straight lines with rounded ends arla a slot cut with an end mill)

I wonder if the base was a cast item pos. alloy not fabricated from steel as the top section has torn off with very little damage to the lower section and base?

See Al They are right You are the one we ask all those hard questions of ,Thankyou !

D.buck

Posted By: David Buck | Posted on: Feb 12, 2012 - 6:49pm
Total Posts: 332 | Joined: May 4, 2008 - 2:59am