RN:
Three submarines loading stores alongside HMS Forth. S class HMS Sibyl (P217) is the inboard boat, with P611 class
P614 alongside. Holy Loch. 1942. Kit-bags and hammocks on the casing indicate that she had probably come from another port in Britain since kit-bags were not carried on patrol.
While the identity of the third sub is unknown, her pennant is N## and while no number is clearly visible, from what is seen I believe the first number looks to be 9.
Considering the ship's general appearance, this would make her a U class, either
Unbeaten (N93) or
Unique (N95). Could also be
Upholder, but there seems to be some contradiction on her pennants (either N99 or P37)
U-class submarine HMS Unshaken (P56) underway
Unshaken was part of the 3rd group of U class submarines, she would spend most of her service in the Mediterranean with a few patrols off Norway. during one of these Northern patrols she would spot a large German force that they believed would attack the convoy PQ 17 and reported it in, due to this and various other sighting the Kreigsmarine cancelled the sortie.
After the Second World War, she was considered obsolete and was scrapped in 1946.