The wreck is a very intact VIIC, which under normal circumstances would be difficult to tell from any other VIICs sunk during Operation Deadlight. However, it had one feature, which makes it very special indeed – a ring-float schnorchel head. U637 was photographed with one prior to being disposed of.
All other features of this wreck, were as per normal late-war VIIC. Life raft canisters on bows.
As to the real identity of the one we dived on DAY 8 – We suggested it was U637, because of its proximity to the sinking position of this U-boat – we were wrong – Our Deadlight photo album proves this. So the nearest type VIIs are U281 and U 1010. The presence of the 88mm gun mounting suggests that U281 is a possibility. However, we are learning that the positional information from official reports of Operation Deadlight is far from accurate. In fact, much of it seems, by today’s standards to be highly unreliable.
Much more work is required to guarantee the identities which we have tentatively given to some of the U-boats we have dived. The one we dived on DAY 7 – is now thought to be U778, thanks to Axel Niestlé’s continued assistance.
Comments:
An interesting day, with at least one mystery surrounding the identities of these submarine wrecks definitely cleared up.
U637 foundered on on 21 Dec 1945 during Operation Deadlight. It was among the first tranche of Deadlight U-boats I found in 2001. A classic U-boat dive in fantastic visibility (Innes McCartney)
Life raft containers have fallen through the superstructure onto the pressure hull (Innes McCartney).
Sky periscope with lovely anemone growth (Innes McCartney)
Rare ring-float snorkel head. I seem to recall this was the first time I encountered this feature on a wreck (Innes McCartney)
Shot of U637’s stern
U637 was fitted with this feature when it surrendered. The location of the wreck and the presence of this feature made the attribution. But there are questions (Innes McCartney).
Foredeck and conning tower intact (Innes McCartney)
Swimming over the conning tower soon revealed the features of a late-war type VIIC U-boat (Innes McCartney)
Very rare to see a gun mount still attached. This one was the base of the 37mm flak gun (Innes McCartney).
Interesting to see that the compass has been unbolted from the repeater binnacle, presumably as a souvenir in 1945 (Innes McCartney)
Completely intact stern (Innes McCartney). 
Close up of the gun mount (Innes McCartney)
Initially the shotline took us down on the underside of the wreck, which lies at 80 degrees over on its starboard side (Innes McCartney)
The diameter of the head is different than in the archive photo. It seems that the outer “jaumann” coating has fallen off, although no trace of it can be seen. Alternatively this is another boat – but which one? We will probably never know (Innes McCartney). 
The foredeck of U637 (Innes McCartney)
Dr. Innes McCartney – Nautical Archaeologist, Naval Historian and 26 years a Wreck Diver.
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