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 Author  Topic: RON 10 ZEBRA STRIPES TO SOLID COLOR
  FRANK

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of FRANK  Posted on: Apr 2, 2009 - 11:34am
Hi Gary-

Many thanks for posting the close up bow shot of the 167 boat after in inflicted damage. That's one amazing shot!

Frank Ryczek, Jr.
Modeler/Friend RON-10 PT-169 " ZEBRA SNAFU "

HIGH TIDES ALWAYS!

YOUR FRIEND THROUGH SCALE SHIP MODELING AND PT BOAT HISTORY!

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Gary Szot

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Gary Szot   Send Email To Gary Szot Posted on: Apr 2, 2009 - 11:41am
You're welcome Frank. Is it true that a torpedo will not arm itself on any non-metallic surface?


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Frank J Andruss Sr

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Frank J Andruss Sr   Send Email To Frank J Andruss Sr Posted on: Apr 2, 2009 - 12:00pm
I am pretty sure a torpedo will arm itself after the props turn a certain number of revolutions, which is why a PT Boat Crew would do everthing they could to jam things into a spinning torpedo prop that got hung up in a tube to stop it...............


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Gary Szot

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Gary Szot   Send Email To Gary Szot Posted on: Apr 2, 2009 - 12:14pm
I guess I should have said detonate rather than arm. The torpedos had a magnetic detonator that would sense a ship's hull. Since PT's are wooden it would not sense it and plow through the boat and out the other side.

Good article on the Mark XIV torpedo

http://www.military.com/Content/MoreContent?file=PRtorpedo


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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 2, 2009 - 12:28pm
Hello again Gary and Frank,
I am unsure about the detonator on Japanese torpedoes (I suspect they were very similar), but I am certain that on American torpedoes they were not possible to "detonate" unless there was forward motion through the water far enough to arm the detonator. (about 200-300 yards) A little paddle wheel inside the detonator is turned by the passing water, and this action extends the detonator (fulminate of mercury) out of its protective shield, cocks the spring loaded firing mechanism, and releases the Flop Ring (Firing Ring) so that it will be able to release the cocked firing mechanism hammer. All of these actions must be complete before detonation is possible.

So the answer to your question would be NO.

The story of torpedoes engines being stopped by stuffing rags, etc. into their propellers was done to prevent the turbines which spin at terrific speed from flying apart and becoming a fragmentation hazard. When the engine is running without the resistance provided by the water, (for example a torpedo stuck inside the tube) the turbine will very quickly reach a speed that would cause the turbine to fly apart into little pieces.
Here is a diagram from the US Naval Weapons Manual that explains the operastion of the detonator used on our Mark 8 and Mark 13 torpedoes.
I hope this is not too convoluted of an explanation. Jerry

Diagram of US Navy Mark 2 Detonator


Explanation of Operation



Jerry Gilmartin

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CJ Willis

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of CJ Willis  Posted on: Apr 2, 2009 - 12:29pm
Frank: On the bottom side up near the nose of the torpedo was a small opening with an impeller inside. This was the arming device. When the torpedo was fired or rolled off the rack, the cover was jerked off this opening allowing the impeller to rotate as the torpedo was going through the water. The torpedo had to go about 50 yards for the impeller to make the necessary rotations to arm. The torpedo was then armed and would explode upon hitting any kind of surface wood, metal or otherwise. When we got Mark X111 torpedos we were cautioned to be sure the covers were on these impeller openings because if the cover was off they could be armed by spray from the boat when underway.

C. J. Willis

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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 2, 2009 - 1:00pm
Me again!
I read CJ's reply and if he says 50 yards I would defer to his memory. I sure would like to get a couple of those arming impeller covers for our boats torpedoes! My 200-300 yard figure came from guesswork and looking at our detonator on the PT 658. Thanks CJ for your comment.
Hey GARY, by the way, you are speaking about detonators armed with a MAGNETIC exploder. I am 90% sure that Jap torpedoes never had magnetic exploders on their air dropped torpedoes, just contact type like ours.

Jerry Gilmartin

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Gary Szot

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of Gary Szot   Send Email To Gary Szot Posted on: Apr 2, 2009 - 1:23pm
Thanks for the clarification Jerry. Check out this web page for the Torpedos the Japanese used during WWII

http://www.combinedfleet.com/torps.htm


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CJ Willis

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Post a Reply To This Topic    Reply With Quotes     Edit Message     View Profile of CJ Willis  Posted on: Apr 2, 2009 - 3:29pm
Jerry: In torpedo school I was told how many revolutions was required for the device to arm but that has been 65 years ago. Can't remember!!!

C. J. Willis

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G R Powell

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Post a Reply To This Topic    Reply With Quotes     Edit Message   Posted on: Apr 2, 2009 - 6:58pm
There have been several intersting issues raised about PT 167:

1. Does the photo I posted show a damaged day room cabin?

Garth, you may be right that the cabin and roof does appear in this photo, but it is not clear to me. Take at look at this enlargement and tell me what you think.



If you look at the height of the port splash shield and then look aft toward the torpedo there appears to be no cabin there. You can see the starboard torpedo. The day room roof was raised just barely above the deck level.

According to 167 CQM Francis Mackey the boat had "no dayroom superstrucure but all flat deck aft." KNIGHTS OF THE SEA, p. 303. Bob Pickett tells me the same thing. The superstructure was smashed when the 167 was extricated from the sinking Stanvac Manila. Here is what I was told by another crew member: "She looked funny with a flat deck instead of a dayroom. The base carpenters said they could not restore the dayroom because it involved factory formed ribs which were critical for new boats. So they "roofed" it over with plain tongue and groove 2x6's. It reduced the headroom in the already low room to about 3 feet as I recall. It was useless for human occupancy and we used it to store extra ammo and such. It was not waterproof even though they tried a couple of times."

2. Could this photo have been taken in November of 1943 since it has roll off racks and not tubes?

If the photo shows the hole in the bow then it had to be taken in November of 1943. Agains the photo is not real clear but it appears to show the hole. Do you see the refelction in the water through the hull? If that is the hole then it would date roll off racks to Novembner of 1943. Here is the cropped photo:



Don't those zebra stripes look bent to you?

Is this photo at Rendova? C.J. remembers seeing the boat at Rendova after it was hit. Francis Mackey says that the 167 was headed to Rendova for engine repair, in company with an LST and an LCI, when the attack occurred. KNIGHTS OF THE SEA, p. 303.



Jerry, you mentioned an article in "LCI Items." Would you mind sneding me a copy?

Thanks all for your interetsing input.


G R Powell

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