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Old 11-03-2021, 02:53 AM   #61
Mister_M
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Good info !

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Originally Posted by iambecomelife View Post
both got sunk because the bright paint on "Janus" helped submarines find their convoy:
Is this clearly stated by the U-boats' captains themselves ?
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Old 11-03-2021, 03:28 AM   #62
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Originally Posted by Mister_M View Post
Good info !



Is this clearly stated by the U-boats' captains themselves ?
It was in a complaint to the Admiralty from an officer on the freighter "Hoyanger", which survived the battle. Not 100% sure that the U-Boat crews confirmed this, but I tend to believe his complaint - he said the "Janus" practically glowed in the moonlight bc of grey and white paint.

Out of curiosity I looked up Janus's shipping company in a WW2 ID book - sure enough the paint scheme for that line was grey and white. They also had bright yellow funnel markings...probably didn't help.

I also read an article on the TM-1 convoy disaster, with 7 of 9 tankers sunk (can't find the web page anymore, sorry) - the destroyers escorting the tankers were painted an inappropriate shade of grey, which the U-Boats used to locate the convoy in the moonlight.

Apparently, certain shades of grey paint made a ship highly visible on a clear night when the moon was out....thus the highly specific regulations about what shade of grey you were supposed to use.
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Old 11-03-2021, 03:36 AM   #63
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Quote:
Originally Posted by iambecomelife View Post
Yep - that's correct. I read a book called "Night of the U-Boats" that talked about the problem created by mixed nationality convoys - the author says UK sailors hated neutral ships; the giant flags & bright colors could give away a convoy's location. In HX-79 British tanker "Sitala" was sailing near the neutral Swedish tanker "Janus" on a moonlit night - both got sunk because the bright paint on "Janus" helped submarines find their convoy:

https://www.uboat.net/allies/merchants/ship/641.html

https://www.uboat.net/allies/merchants/ship/638.html
THe bright paint is moot on a moonlit night in a two convoy attack:
Quote:
HX 79 was an east-bound convoy of 50 ships which sailed from Halifax on 8 October 1940 making for Liverpool with war materials. On 19 October, 4 days from landfall, HX 79 was entering the Western Approaches, and had caught up with the position of SC 7, which was under attack.
The escort for the crossing had been meagre, being provided by two armed merchant cruisers against the possibility of attack by a surface raider, but even these had departed when HX 79 was sighted by U-47, commanded by submarine ace Kapitänleutnant Günther Prien.
At this point HX 79 was unescorted; Prien sent a sighting report and set to shadowing the convoy, while Konteradmiral Karl Dönitz ordered the pack to assemble. Those U-boats which had attacked SC 7 and were still able to fight (three had departed to re-arm having expended all their torpedoes) were directed to the scene. Four did so, U-100 (Joachim Schepke), U-46 (Engelbert Endrass), U-48 (Heinrich Bleichrodt) and U-38 (Heinrich Liebe) joining U-47 during the day.
However the Admiralty, concerned by the fate of SC 7 and anticipating an attack, rushed reinforcements to the scene; throughout the day a large escort force of 11 warships also gathered to provide cover.
Action
Undeterred by their presence however, the pack attacked as night fell; using the darkness to cover an approach on the surface, Prien penetrated the escort screen from the south to attack from within the convoy, while Endrass (who had learned his trade as Prien's 1st officer), did the same from the north.
Over the next six hours, 13 ships were torpedoed; 6 by U-47 alone (4 of which were sunk). 10 ships were sunk from the convoy, and 2 stragglers were lost later in the day. These were Shirak, which had been torpedoed in the night, and Loch Lomond, sailing with the convoy as a rescue ship. Another, Athelmonarch, was damaged but was able to make port.
HX 79 had lost 12 ships out of 49, a total tonnage of 75,069 gross register tons (GRT).
None of the attacking U-boats were damaged.
In short the Convoy had happened upon a convoy attack in progress (SC 7) ; was spotted by Prien and shadowed and the other Uboats, all commanded by top aces, closed in to commenced night attacks in moonlight. HX 79 may be considered to have gotten off lightly when compared to SC 7:
Quote:
SC 7 had lost 20 ships out of 35, of which seven fell to Kretschmer's U-99. The total tonnage lost was 79,592 GRT. The arrival of convoy HX 79 in the vicinity had diverted the U-boats and they went on to sink 12 ships from HX 79 that night. No U-boats were lost in either engagement. The loss of 28 ships in 48 hours made 18 and 19 October the worst two days for shipping losses in the entire Atlantic campaign. The attack on SC 7 was a vindication of the U-boat Arm's wolfpack tactic, and was the most successful U-boat attack of the Atlantic campaign. The convoy escort was ineffective in guarding against the attack. Convoy tactics were rudimentary at this early stage of the war. The escorts' responses were uncoordinated, as the ships were unused to working together with a common battle-plan. Command fell to the senior officer present, and could change as each new ship arrived. The escorts were torn between staying with the convoy, abandoning survivors in the water, as DEMS regulations demanded, and picking them up, leaving the convoy unprotected and risking being torpedoed themselves.
When U say Happy Time BBY, this was the Apogee of the entire Uboat campaign!
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Last edited by Aktungbby; 11-03-2021 at 03:44 AM.
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Old 11-03-2021, 06:42 AM   #64
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Quote:
Originally Posted by iambecomelife View Post
...the destroyers escorting the tankers were painted an inappropriate shade of grey, which the U-Boats used to locate the convoy in the moonlight.

Apparently, certain shades of grey paint made a ship highly visible on a clear night when the moon was out....thus the highly specific regulations about what shade of grey you were supposed to use.
I think that's why dark/black hulls were not repainted : it was very good to camouflage the ship at night. Only ships with white/bright/saturated colors were repainted with medium/dark grey paint.

To confirm this, it would be useful to find original (peace time) paint sheme of these ships :

Quote:
Originally Posted by Mister_M View Post
3. Ships with superstructures (probably) repainted in grey : the hull remains very dark (black). HEINA superstructures are perhaps actually white...

 


4. Ships in plain grey (probably a war repaint) : note that there are different shades of grey from ship to ship...

 
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Old 11-03-2021, 12:16 PM   #65
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Quote:
Originally Posted by iambecomelife View Post
Interesting photos of colored sketches below, showing how ship camouflage changed from WWI - they are of the standard "War" class merchantman "War Drake" in 1918 and the long bridge deck merchant "Clearpool".

It seems they decided in WW2 that the complicated dazzle camouflage was not very effective
Description of second image says:

"Dazzle painting was not used as she would almost always be sailing in convoy"

...which kinda makes sense: dazzle does not help to hide a ship, only obscure its AOB, but if your target is in convoy accompanied by several rows of ships all sharing same course and speed, you have more ways to gather data then eyeballing a single target?

No idea if this was really the reasoning behind dropping dazzle of course.
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Old 11-04-2021, 02:44 AM   #66
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Originally Posted by Mister_M View Post
I think that's why dark/black hulls were not repainted : it was very good to camouflage the ship at night. Only ships with white/bright/saturated colors were repainted with medium/dark grey paint.

To confirm this, it would be useful to find original (peace time) paint sheme of these ships :
The first ship I've searched for tends to confirm my hypothesis : Mercier had white superstructures (https://uboat.net/allies/merchants/ship/986.html).

Same for Talthybius : https://www.subsim.com/radioroom/sho...29&postcount=1

Phidias had white superstructures and a black strip at the top of the stack (https://uboat.net/allies/merchants/ship/982.html).

Daru : https://www.wrecksite.eu/img/wrecks/z_daru_mv.jpg

Sally Maersk : https://uboat.net/allies/merchants/ship/1089.html

...

So, finally, it seems that it was more important to remove white surfaces than black ones.

Last edited by Mister_M; 11-04-2021 at 08:21 AM.
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Old 11-04-2021, 10:12 PM   #67
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Quote:
Originally Posted by kapuhy View Post
Description of second image says:

"Dazzle painting was not used as she would almost always be sailing in convoy"

...which kinda makes sense: dazzle does not help to hide a ship, only obscure its AOB, but if your target is in convoy accompanied by several rows of ships all sharing same course and speed, you have more ways to gather data then eyeballing a single target?

No idea if this was really the reasoning behind dropping dazzle of course.
Quote:
Originally Posted by Mister_M View Post
I think that's why dark/black hulls were not repainted : it was very good to camouflage the ship at night. Only ships with white/bright/saturated colors were repainted with medium/dark grey paint.

To confirm this, it would be useful to find original (peace time) paint sheme of these ships :
I am pretty sure Talthybius was an Alfred Holt co. ship, so her colors would have been white superstructure with brown trim, brown masts, blue funnel, & black hull. Not sure about the others....unfortunately they are not as distinct looking as the Blue Funnelers and I will have to look up!
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Old 11-06-2021, 07:05 AM   #68
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So, to start again from the beginning :

Quote:
Originally Posted by gap View Post
* Grey paint was the general rule for Allied merchant vessels. Some ships had funnel tops and top half of masts painted white so to blend with the sky.
* Ships built during the war were delivered in grey paint.
An important detail is missing : what shade of grey was it ? Since it appears than certain shades of grey would give position to the u-boats at full moon nights :

Quote:
Originally Posted by iambecomelife View Post
the destroyers escorting the tankers were painted an inappropriate shade of grey, which the U-Boats used to locate the convoy in the moonlight.

Apparently, certain shades of grey paint made a ship highly visible on a clear night when the moon was out....thus the highly specific regulations about what shade of grey you were supposed to use.
You partially answered the question by publishing the "official" colors, but we don't know what exact grey color used the merchants...

Quote:
Originally Posted by iambecomelife View Post
"Janus" practically glowed in the moonlight because of grey and white paint.

Out of curiosity I looked up Janus's shipping company in a WW2 ID book - sure enough the paint scheme for that line was grey and white.
Janus' peace paint sheme was probably the same as Mercier's one which was light grey : https://uboat.net/allies/merchants/ship/986.html

Quote:
Originally Posted by gap View Post
* As a consequence of the previous point, there was not a sudden transition from peacetime colours to wartime grey. Some ships - probably the ones whose trading routes were closer to the main war theatres - were repainted at the earliest opportunity after the war broke out, whereas a few others are reported to have switched colours as late as January 1941.
And probably many changed much more later... or never.

Quote:
Originally Posted by gap View Post
* The implementation of safety rules was somehow more strict for ships sailing in convoys. These rules included:
  • no dark funnel smokes (this would have ruled out old coal-burning steamers from convoys).
There were "fast" and "slow" convoys. The latters probably were for old coal steamers (which produced dark smoke)... So this "rule" was only for fast convoys...

Quote:
Originally Posted by gap View Post
* neutral ships retained their company colours for most of the war even when sailing in convoys. If I can add a personal note, this might have been sort of a nonsense. According to German engagement rules any ship sailing within Allied convoys, even though belonging to a neutral nation, would have been a valid target, and retaining peacetime colours would only have made her an easier prey. In other words, convoy protection would have nullified "neutrality privileges" or, even worse, it could have rendered them counterproductive, but this is probably something which was not so clear at that time.
Answer :

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Originally Posted by kapuhy View Post
Possibly because you do not intend to stay in the convoy for entire cruise and don't want to have to paint them back on when you separate from it. Plus, there's a small chance that given two equally juicy targets in the periscope, U-Boat will select one that belongs to the enemy nation.
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