ID'ing of an 'object' wedged under torpedo tubes

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marcelo_malara
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by marcelo_malara »

Kevin, I understand that this is the chart of the battle. I see no use of torpedoes at that distance. Longest range for the Mk IX** is 15.000 yards. Moreover, nobody would expect to hit at distance a manouvering ship.
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by Kev D »

marcelo_malara wrote: Thu May 19, 2022 6:49 pm
Kevin, I understand that this is the chart of the battle. I see no use of torpedoes at that distance. Longest range for the Mk IX** is 15.000 yards. Moreover, nobody would expect to hit at distance a manouvering ship.
Well yes that is Capt.Gordons 'chart' from his book (Fight It Out, IIRC) and again IIRC, for circa 11.00hrs. [See below excerpt from his AAR for that time.] Given all ships records were lost on sinking, this chart was drawn from 'memory' and notes he made from info gathered soon after he was in the prison camp at Makassar and kept in a toothpaste tube throughout his incarceration in Japan, and then the info used on his return to UK for help in writing his AAR at that time (and one assumes drawing his chart). So the charts accuracy is to be, if not actually disrecarded, at least open to question re timings and distances.

However there is no doubt that the port tubes were fired, and it seems at around that time on the chart, which was towards the end of the action and not that long prior to the fatal shell hit.

41. The action continued much as previously described. Neither EXETER nor destroyers had yet been hit but now, despite the use of smoke (from funnel and smoke floats), salvos were falling close and snaking was necessary to avoid being hit. At one time it was seen that a number of EXETER's salvos straddled the leading enemy cruiser on the starboard beam, but with smoke interference it was impossible to say if hits were obtained. A torpedo target at long range was presented by the two enemy cruisers on the port quarter at about 1100. As the enemy were making no attempt to close the range and so provide a better target, the port tubes were fired. No hits were obtained, the target ships taking avoiding action by alteration of course.
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by Kev D »

Below is a short Jap version of events circa that time and the Jap action chart for the full battle.

Note. In the text the word Ikazuchi should be replaced by Inazuma. This is an age old mistake passed on down the years (the actual Japanese lettering from Ikazuchi and Inazuma are very similar and easy to mix up, see below.) Long story short, Ikazuchi left earlier in morning before action started and did not return again until the rescue was ongoing (and it was always Inazuma that claimed the two torp hits to Exeter anyway).

Note also that the times in both are Jap times (i.e. Tokyo time) which was 90 mins (1.30hrs) later than Allied times.
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We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by marcelo_malara »

Yes, I miss something. Torpedoes are close in speed to surface warships, so to hit you have to aim the fishes well ahead of target. A rough estimate in Gordon´s chart, assuming the Japanese were sailing at 30 knots, and the Mk IX were set at about the same speed to maximize range, shows that the torpedoes had to be fired almost abeam, and so the distance run at hit time was about 13400 yards.


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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by Kev D »

Well, unless someone elese joins in and proves / suggests otherwise I am willing to accept that it is a torp warhead. Look is basically identical and measuremnts well with the catchers range, let alone the ball park.

One point that was brought up elswhere, although the poster was in agreement that it certainly looks l8ke a warhead, is that it is missing it's arming impeller.

My reply was "Maybe the one in question had not yet been 'armed', or the impeller has 'fallen off' / corroded away over the years underwater".
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We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by wadinga »

Hi All,

Please don't take this as criticism but I believe these six projections are actually nicknamed "whiskers" and are designed to ensure contact detonation even at higher angles of impact on the hull. The impeller driven around by the passage of the weapon through the water is a small "paddle wheel" further down the body of the torpedo.

Marcelo's diagram neatly shows the extremely low chances of getting a torpedo hit at these very long ranges where any inaccuracy in estimating initial target sped or course or any changes during the many minutes of the torpedoes' travel means a miss. Even mass launches at longer ranges secured very few hits, and sometimes none at all.

I believe it is possible the object is a practice head which might have been stowed on the upper deck and come adrift. The complexity of the torpedo's internal machinery meant servicing and testing was a fairly frequent requirement.

Not that I would advise any diver to take any chances. I remember seeing a TV documentary where a diver was sitting on deck enthusiastically hammering concretions off a giant bottle shaped object recovered from the Lusitania wreck site. Luckily he found out it was an unexploded "hedgehog" projectile which had lost its fins before he went too far. The wreck was apparently often used as an ASDIC target during WWII.

All the best

wadinga
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by marcelo_malara »

wadinga wrote: Sat May 21, 2022 7:12 pm I believe these six projections are actually nicknamed "whiskers" and are designed to ensure contact detonation even at higher angles of impact on the hull. The impeller driven around by the passage of the weapon through the water is a small "paddle wheel" further down the body of the torpedo.


wadinga
Hi Wadinga. I believe that in this pistol whiskers and propellers are the same piece. There is an interesting posting in the web:

https://uboat.net/forums/read.php?20,92977,92988

"Generally, it was impact pistol with 6 whiskers acting as impeller, moving the boost charge forward (toward the firing pins), as the torpedo traveled the safety distance. Moreover, the rotating impeller tensed the firing spring. When the whiskers strike the target, they pushed the shaft, the shaft released the firing pins, which forced by the firing spring hit the boost charge."

The impeller you describes was used in the USN:

http://archive.hnsa.org/doc/torpedo/#pg17

In this case the wheel also runs a small generator, as the firing was electrical and not mechanical.
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by marcelo_malara »

wadinga wrote: Sat May 21, 2022 7:12 pm
the extremely low chances of getting a torpedo hit at these very long ranges where any inaccuracy in estimating initial target sped or course or any changes during the many minutes of the torpedoes' travel means a miss. Even mass launches at longer ranges secured very few hits, and sometimes none at all.

wadinga
I agree with this, about two hundred torpedoes were fired in Jutland to little avail. Anyway I think that Capt Gordon may have fired them:

1-to diminish the risk of a shell detonating one

2-a torpedo in the water certainly would have made the Japanese change course, even for a while, making them fall a little more astern, and, may be, allowing Exeter to escape. A desperate measure without doubt.
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by wadinga »

Hi All,

Sorry to seem obstinate, but close inspection of the photo provided, suggests to me there is no "twist" in the whisker blades and therefore no rotational force generated. Their front to back dimension is tiny, and the German example referenced has a dedicated impeller with a pronounced twist as well as its own whiskers.

If you can see it on You Tube this RAF instructional film for the air launched Mk XII shows the whiskers in more detail and at no time is it suggested the whiskers screw down to arm the weapon. https://www.youtube.com/watch?v=JweZK_ii8c4

It also has fascinating detail on the taut-wire and airtail system used to ensure the torpedo hit the water at the right angle, unnecessary in surface or submarine launches.

Whether the Mk VIII contact exploder is different i don't know. but it seems unlikely.

Marcelo, you may recall we discussed some while ago the many tens of torpedoes fired by the Japanese at very long range at Java Sea to secure a few (but critical) hits. That was at a "battke line" providing a lengthy non-manoeuvring target. I think Exeter's effort was a Forlorn Hope

"Getting rid of poorly protected warheads on the upper deck as quickly as possible in a gunfight seems like a good idea to me. :cool:

All the best

wadinga
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by Kev D »

wadinga wrote: Mon May 23, 2022 9:48 am I think Exeter's effort was a Forlorn Hope

"Getting rid of poorly protected warheads on the upper deck as quickly as possible in a gunfight seems like a good idea to me. :cool:

All the best

wadinga
Re '...........was a Forlorn Hope", even Captain Gordon thought so; to quote from his AAR - "A torpedo target at long range was presented by the two enemy cruisers on the port quarter at about 1100. As the enemy were making no attempt to close the range and so provide a better target, the port tubes were fired. No hits were obtained, the target ships taking avoiding action by alteration of course."

So the alteration of course, however slight, may have given Exeter a short (very) respite, at least from the northern two cruisers (Ashigara and Myoko).
We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by wadinga »

Hi Kev D,

The Japanese might have spotted the splashes of the torpedoes entering the water at 9 miles range,, but may equally have changed course for other reasons. The approx, 5 minute run time for 13,400 yds is a long period during which nothing must change.

Great work on the new material you have supplied. :ok:

All the best

wadinga
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by Kev D »

wadinga wrote: Mon May 23, 2022 12:02 pmHi Kev D,
The Japanese might have spotted the splashes of the torpedoes entering the water at 9 miles range,, but may equally have changed course for other reasons. The approx, 5 minute run time for 13,400 yds is a long period during which nothing must change.

Great work on the new material you have supplied. :ok:

All the best

wadinga
Thanks Wadinga.

The original IJN AAR chart (I posted up-thread) does not show any course change at 1100 hrs, but this one below from Senshi Sosho - more or less a copy of the original - does show one but much later. Times on chart are Japanese (90 mins later than Allied), so the red dot shows where Captain Gordon's 11.00am would be.

Kevin
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We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by marcelo_malara »

wadinga wrote: Mon May 23, 2022 9:48 am
Sorry to seem obstinate, but close inspection of the photo provided, suggests to me there is no "twist" in the whisker blades and therefore no rotational force generated. Their front to back dimension is tiny, and the German example referenced has a dedicated impeller with a pronounced twist as well as its own whiskers.
Hi Wadinga. The need for an arming mechanism can not be denied. If this was not in the nose it has to be somewhere. But that would be faulty engineering, because you would need to provide two apertures in the warhead and somehow they had to be interconnected, because both functions are related. I agree that there is not visible twist, but enlarging the image I find out that the whiskers have an airfoil shape, that passing thru a stream would make them to rotate clockwise as seen from the front of the torpedo.

Regards

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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by Kev D »

A slight thread hijack here, but.............................another 'oddity' from the same day as it were.

The below historical photos purport to show Ashigara and Myoko (foreground) firing at Exeter and cohort on 1-March-42,

However, as can be seen they (well, Ashigara) are firing to port, but the only time this is possible is where I have marked with a green dot on 'chart'. At other times they would be firing to starboard. Interesting (to me anyway :D ), given that time is right when Exeter was literally going under. So certainly in the realm of the possible of course.
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We are off to look for trouble. I expect we shall find it.” Capt. Tennant. HMS Repulse. Dec. 8 1941
A review of the situation at about 1100 was not encouraging.” Capt. Gordon, HMS Exeter. 1 March 1942
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Re: ID'ing of an 'object' wedged under torpedo tubes

Post by Natter »

Kev D wrote: Wed May 18, 2022 6:44 amAnother pic of a torp body without warhead, showing those slots for the bolts to attach the warhead.
UK Mk VIII torpedoes in Kaholmen torpedobattery, Oscarsborg (Oslofiord, Norway)
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