Immediately prior to the war, the most common scheme within the U-boat fleet consisted of Dunkelgrau 51 on the upper hulls and towers. Very soon after the start of hostilities the Dunkelgrau 51 paint on a few U-boats such as U 30 was replaced by Hellgrau 50. Over the course of the winter of 1939, the Hellgrau 50 paint gradually became as common as Dunkelgrau 51. Many of the U-boats which were completed in 1940 (such as U 69, U 94, U 99 and U 552) sported this light grey Hellgrau 50 colour during their commissioning ceremony.

The contention by some that most wartime U-boats were the light grey Hellgrau 50 is wholly inaccurate, as both Hellgrau 50 and Dunkelgrau 51 were commonly used upon wartime U-boats. The common use of both these colours is supported by the well-researched 3-part decal sheet by U.L.A.D.-decal for the Revell 1/72nd Type VIIC U-boat kit.

Another colour which was used was Schlickgrau 58. Blaugrau 58/1 and Dunkelgrau 52 were much less common, and Blauschwarz 58/2 was hardly used at all. According to Randy Short of Snyder & Short Enterprises, Blauschwarz 58/2 was not used at all upon Type VIIs. Dunkelgrau 53 was used in camouflage patterns, but was rarely (if at all) used as a sole upper colour.

It would have been somewhat helpful if the painting regulations had stated which of the Kriegsmarine paints were to have been used upon the upper hulls and conning towers of U-boats. Unfortunately they don’t, and so are of limited use to us. The painting regulations stated only that shipyards had to ask the High Command for instructions on painting the upper colour of each individual boat, and that the U-boat’s planned operational area would often influence the shade of grey used. The latter does help us with the boats which served in the Arctic and in the Mediterranean, and shall be discussed shortly.

The regulations offer absolutely no help to us on the question of which of the three most common colours - Hellgrau 50, Dunkelgrau 51 or Schlickgrau 58 - was used on boats serving in the Atlantic or training in the Baltic. All we can do is attempt the difficult and often frustrating task of photographic interpretation. It is very difficult to differentiate between Hellgrau 50 and Dunkelgrau 51 in black and white photos where no reference point is available. In general terms, the Hellgrau 50 paint looks very light – even white – in photos where the sun is shining upon the surface in question. Dunkelgrau 51 can look light when there was a lot of light present in the photograph, but does not ever look white like the Hellgrau 50 sometimes does. For modellers attempting to determine whether their chosen subject was Hellgrau 50 or Dunkelgrau 51, it is advisable to study photographs of warships where these colours are known to have been used (as previously mentioned the superstructures of pre-war and early wartime vessels were Hellgrau 50 and the upper hulls were Dunkelgrau 51). Although a marked contrast between these colours can be seen in photos of Kriegsmarine warships, it is still very difficult – sometimes impossible – to distinguish whether one or the other was used on a U-boat merely by photographic interpretation. Such an exercise is often extremely frustrating and highly subjective.

It has already been mentioned that the painting regulations stated that shipyards had to ask the High Command for instructions on painting the upper colour of each individual boat. Since some U-boats served in different locations during their career, some sported different colours at various times. It is quite likely that the commanders and the bosses at the shipyards would also have had an influence over which upper colours were used. Such individuality between boats can be illustrated with U 47 and U 99. Both these famous U-boats served in the Atlantic, were based at Lorient toward the end of their careers, and were sunk in March 1941. The upper colour of U 47 was Dunkelgrau 51 until the summer of 1940, when it was changed to a darker shade that may have been Schlickgrau 58. U 99, on the other hand, was Hellgrau 50 throughout its illustrious career. This was perhaps because at the time U 47 was launched Dunkelgrau 51 was the prominent colour, and when U 99 was launched it was more usual for Hellgrau 50 to be used.

In the case of the U-boats serving in the Mediterranean, the theatre of operations did make a difference since it was commonplace for camouflage to have been used in that area. The same can be said for the Arctic, where conning towers were sometimes painted white. U-boats operating out of Norway frequently had the upper half of the conning tower, above the spray deflector, or all of their conning tower, painted white. This was intended to allow the boat to blend in better with the sea mists and fogs that often hang close to the surface of the water in high latitudes.

An order was placed by the High Command on the 7th May 1943 to the effect that only the petrol-proof camouflage colours Schlickgrau 58, Blaugrau 58/1 and Blauschwarz 58/2 were to be used as upper colours on operational U-boats. This was the only order specifically pertaining to U-boat colours. The reason given is that the High Command was worried at this time that the Allies were using infra-red sensors to detect the U-boats. Presumably these paints did not reduce the infra-red signature of a U-boat. Instead, the High Command, who were alarmed at the number of U-boats being sunk at that time by aircraft, must have deemed that these darker colours would render a U-boat less visible to enemy aircraft. This order seems not to have been adhered to, as the light and medium greys were still used until the war’s end.

Early in the war standard colours had been commonly used within the U-boat fleet. However, as the war progressed non-standard greys were being used due to the wartime shortages. By the end of the war, darker colours were more common than had been the case at the start of the conflict. The colour photographs of U 505, U 805 and U 858 all show medium blue-grey (probably Dunkelgrau 51) upper hulls and very dark blue conning towers (possibly Blauschwarz 58/2?)

Conning towers and upper hulls were sometimes different colours, especially later in the war. Such was the case on U 995, which at some point in its career had a medium-to-dark upper hull and a white or Hellgrau 50 tower, and U 162, which had a Dunkelgrau 51 upper hull and a Hellgrau 50 tower. In rarer cases such as U 302 in the summer of 1942, the upper and lower halves of the conning tower were different colours.

The following U-boats may have had these upper colours. The colours are merely educated guesses, and can in no way be guaranteed –

U 30
Pre-war - Dunkelgrau 51
November 1939 - Hellgrau 50
1942 (training flotilla) - Schlickgrau 58

U 35
3rd November 1936 (commissioning) - Hellgrau 50
1937 - Dunkelgrau 52
5th February 1938 - Dunkelgrau 51 + Spanish Civil War stripes
17th June 1938 to October 1939 - Dunkelgrau 51

U 37
Pre-war - Dunkelgrau 51
1942 (training flotilla) - Dunkelgrau 52 or Dunkelgrau 53

U 47
December 1938 to July 1940 - Dunkelgrau 51
August 1940 to March 1941 - Schlickgrau 58

U 48
September 1939 - Dunkelgrau 51

U 69
19th September 1940 (launch) - Hellgrau 50

U 73
April 1941 - Dunkelgrau 51

U 86
Summer 1942 - Dunkelgrau 51

U 94
12th June 1940 (launch) - Hellgrau 50
18th April 1941 - Hellgrau 50
1942 - Dunkelgrau 51

U 95
24th February 1941 - Schlickgrau 58

U 99
Throughout career - Hellgrau 50

U 128
May 1941 (UAK trials) - Hellgrau 50

U 162
August 1942 - Dunkelgrau 51 upper hull and Hellgrau 50 tower

U 163
April/May 1942 - Dunkelgrau 51

U 203
4th January 1941 (commissioning) - Dunkelgrau 51

U 267
April 1943 - Dunkelgrau 51

U 302
Summer 1942 (training) - Dunkelgrau 51 upper hull; Dunkelgrau 51 on lower half of tower; Schlickgrau 58 on upper section with yellow training band
September 1943 - Hellgrau 50

U 335
April/May 1942 - Dunkelgrau 51

U 362
30th July 1944 - Weiß 30 upper hull and lower half of tower; upper half of tower dark grey
End of 1944 - Weiß 30

U 405
April 1943 - Hellgrau 50

U 438
May 1943 (sinking) - Schlickgrau 58

U 441
21st February 1942 (commissioning) - Hellgrau 50
Summer 1942 (5th U-Flottille) - Hellgrau 50 upper hull and Dunkelgrau 51 tower

U 442
12th January 1942 (launching) - Hellgrau 50

U 505
4th June 1944 (capture) - Dunkelgrau 51 upper hull and Blauschwarz 58/2 (?) tower

U 552
Throughout operational career - Hellgrau 50

U 558
June 1942 - Dunkelgrau 51

U 564
11th July 1942 - Dunkelgrau 51

U 673
Flak-trap - Schlickgrau 58 (?)

U 751
Late 1941 - Hellgrau 50

U 805
14th May 1945 (after capture) - Dunkelgrau 51 upper hull and Blauschwarz 58/2 (?) tower