I have just completed a small diorama featuring a World War 2 British submarine approaching a home port. In addition to the Union Jack and White Ensign, would the vessel show other flags or pennants in this scenario? If so, where would these be flown on the submarine?

A Jolly Roger (Skull and Crossbones Pirate flag) with various symbols added - white bars for successful patrols, etc. Sorry, don't have a reference for the symbols used. The Jolly Roger was flown from a periscope mast, a radio mast, a jury rigged stick, rigged between the masts or hung on the conning tower (sail) - whatever was convenient, no standard practice.

Tradition began spontaneously, as I recall, in WW1 with Max Horton and E9, was started anew in WW2 and carries on to this day. HMS Conqueror flew the Jolly Roger after sinking the Argentine cruiser ARA General Belgrano (ex-USS Phoenix, CL-46). During the Gulf Wars and action against Libya, RN submarines also flew the Jolly Roger, emblazoned with one tomahawk symbol for each tomahawk missile launched. USN silent service follows this tradition as well.

The USN Silent Service also displayed a broom when they had a clean sweep, which I believe that every attack was successful.

Mark

Thanks for that information.
Would there also be flags denoting the vessel's number, and one indicating its arrival at port?

Submarines - "ships that sink on purpose" - by WW2 tended to minimize topside gear as it impairs speed, is a maintenance problem because it is underwater so much. They didn't really carry a mast with yardarm and signal flag hoists. If they did have some flag hoist capability, they'd hoist their call sign using signal flags rather than pennant/hull number. For RN subs, some painted their pennant number on the side of conning tower in white letters.

The Jolly Roger hoist I previously mentioned was usually some temporary jury rig. What one might find in the way of other flags is a paying-off pennant (commissioning pennant) flown on a sub coming into port to be taken out of service.

Suggest an idea for your diorama would be to have quartermaster crewmen using the signaling lamp to flash a recognition signal or using hand-held semaphore flags. Also you can "Station the special sea and anchor detail", a line of deck hands well forward, not many, but enough to render salutes, work the anchors or tie up to a buoy, and handle lines.

I suggest these because many warship dioramas I've seen have sailors placed randomly around the vessel not doing anything particularly salty sailor-like. Believe your diorama would be brought beyond the ordinary if you put the sailors to work doing the standard tasks one does when coming in to port - adds realism.

Hope this helps...

Kip

If you find yourself down in Portsmouth, the Submarine museum has several WWII British 'Jolly rogers' on display, unfortunately I didn't take any photos of them when I was there earlier in the year.

Displayed on a Jolly Roger would be markings for:
Ships sunk
Agent insertion
Rescue mission
Trains attacked (yes this did happen, if I remember, on the coast of Italy)
Main laying
Tanks attacked
Aircraft shot down
plus others

Many thanks to you all for most informative responses.
The simple diorama is now almost complete. I'm reasonably satisfied with the result, particularly as it's somewhat out of my comfort zone (more used to land-based military dioramas). I was tempted to add some crew to the submarine, but the scale of 1/400 ruled this out. Yes, I could have scratch-built a couple of suitable figures to man the conning tower, but maybe I'll give that a try next time.
To be honest, the most challenging aspect was creating a realistic sea surface, but again, that worked out well in the end.
My next naval project is to be a 'forced perspective' diorama, showing a Kamikaze Zero diving towards a US battleship. On this occasion, I plan to use a 1/144-scale aircraft and a 1/2000-scale ship … the completed scene to be viewed from above … well that's the idea at least. How it works out is another matter.