Battle of Heligoland Bight Order of Battle

SMS Mainz Sinking with HMS Lurcher standing by to rescue survivors.  Over 200 of her crew were saved including Wolf von Tirpitz, son of Grand Admiral Tirpitz.  Rear Admiral Maass was not one of the survivors.

British

First Battlecruiser Squadron
Lion (Vice-Admiral Beatty)
Queen Mary
Princess Royal

Cruiser Force K
Invincible (Rear-Admiral Moore)
New Zealand

Destroyers detached from First Destroyer Flotilla
Badger
Beaver
Jackal
Sandfly

Cruiser Force C (Seventh Cruiser Squadron)
Euryalus (Rear-Admiral Christian)
Bacchante
Cressy
Hogue
Aboukir
Amethyst

First Light Cruiser Squadron
Southampton (Commodore Goodenough)
Birmingham
Falmouth
Nottingham
Lowestoft
Liverpool

Harwich Force

Third Destroyer Flotilla
Arethusa (Commodore Tyrwhitt) (Light Cruiser)
Laurel
Liberty
Lysander
Laertes
Laforey
Lawford
Louis
Lydiard
Lark
Lance
Linnet
Landrail
Lookout
Leonidas
Legion
Lennox

First Destroyer Flotilla
Fearless (Captain Blunt)(Light Cruiser)
Goshawk
Lizard
Phoenix
Lapwing
Ferret
Forester
Defender
Druid
Ariel
Lucifer
Llewellyn
Acheron
Attack
Hind
Archer

Submarine Flotilla
Lurcher (Commodore Keyes) (Destroyer)
Firedrake (Destroyer)
E4
E5
E6
E7
E8
E9
D2
D8

German

Outer Patrol Line
I Torpedo Boat Flotilla
V187 (Commander Wallis)
V188
V189
V190
V191
G197
G196
G193
G194

G192 and G195 were also part of this flotilla but not present at the time of the Battle of Heligoland Bight.

Inner Patrol Line
III Minesweeping Division
D8 (Lieutenant-Commander Wolfram)
T25
T29
T31
T33
T34
T35
T36
T37
T49
T71
S73

Supporting Light Cruisers
Ariadne
Stettin
Frauenlob
Hela

Reinforcement
V Torpedo Boat Flotilla
G12 (Commander von dem Knesebeck)
V1
V2
V3
V6
S13
G7
G9
G10
G11

G8 was also part of this flotilla but not thought to be present at the time of the Battle of Heligoland Bight.

Light Cruisers allocated to the Patrol
Cöln (Rear Admiral Maass)
Mainz
Strassburg
Stralsund
Kolberg
Danzig
München

Thanks (again) to Peter Klein for supplying the details of German light forces from the German sources.

SMS Mainz in happier times.  Like Cöln she was a Kolberg class light cruiser.  All four ships of the class had different turbines and screws, Mainz being the only one with only two shafts and AEG-Curtiss turbines.